JP6663183B2 - Method and apparatus for modeling objects - Google Patents

Description

  The present invention relates to a method and an apparatus for modeling an object.

  2. Description of the Related Art In the field of computer graphics (CG), particularly fluid simulation in the field of Visual Effects (VFX), research for solving the fluid flow numerically has been continuously conducted. The Navier-Stokes Equation describes a fluid as a sum of extremely small particles and shows how each particle interacts and moves. The Navier-Stokes equation may turn into a simpler Bernoulli's principle when assuming ideal situations. In order to realistically reproduce the fluid modeling based on the Navier-Stokes equation, the incompressibility condition must be satisfied.

  Further, in the simulation for the deformed object, the reaction of the model must be performed in real time, and at the same time, the accuracy of the calculation for a natural degree to be visually observed must be guaranteed. For this purpose, a model that mainly takes into account the physical properties of the deformable body, boundary conditions, and externally acting forces is mainly used.

  In the field of computer graphics, a simulation for a fluid and a simulation for a deformed body are individually performed, but an environment in which the fluid and the deformed body coexist and affect each other is general.

  An object of the present invention is to separate a solid-state simulation from a fluid-state simulation by utilizing a grid for an area adjacent to an object having dissimilar characteristics, and to save a volume required when modeling each of a solid and a fluid. It is to achieve such constraints individually.

  Another object of the present invention is to allow the relative modeling module to use the information stored in the background grid and reflect it at the time of its own modeling, thereby real-time processing the interaction between the solid and the fluid, and process the fluid and the solid mixed with the fluid. It is to model realistically.

  According to one embodiment, a method of modeling an object includes detecting an adjacent region between a first object modeled from a particle and a second object modeled from a particle, and defining a grid for the adjacent region. Defining, using the information stored at the grid points of the grid, calculating the acting force between the first object and the second object in the adjacent area, based on the acting force Modeling the first object and the second object.

  The step of defining the grid comprises: extracting a distance value between a contour of the first object or the second object in the adjacent region and a grid point of the grid adjacent to the contour; At the lattice point.

  The step of calculating the acting force includes: determining whether a collision has occurred between the particles of the first object and the particles of the second object in the adjacent region; and Calculating an acting force between the particles of the first object and the particles of the second object.

  The step of determining whether or not the collision has occurred includes the step of determining whether or not the collision has occurred using a distance value stored at a grid point adjacent to the position of the particle of the first object. May be.

  The step of determining whether the collision has occurred may further consider whether the particles of the first object satisfy a volume storage condition.

  The step of calculating the acting force includes detecting, when it is determined that the collision has occurred, particles of the first object having collided among particles of the first object and particles of the second object in the adjacent area. And re-defining the positions of the detected particles of the first object. Based on the re-defined positions of the particles of the first object, the action force exerted on the second object by the collision is determined. And calculating.

  The step of redefining the positions of the detected particles of the first object may include the step of redefining the positions of the detected particles of the first object so as not to penetrate the second object.

  The step of redefining the positions of the particles of the detected first object is performed using a distance value and a gradient stored at a grid point corresponding to a cell including the particles of the detected first object. Calculating the moving direction and the shortest moving distance of the particles of the first object that do not penetrate the two objects; and moving the position of the particles of the first object based on the calculated moving direction and the shortest moving distance. May be.

  Calculating the moving speed of the particles of the first object using the distance value stored at the grid point and the calculated shortest moving distance; and calculating the calculated moving speed of the detected first object. Storing at a grid point corresponding to the cell containing the particles.

  Calculating the acting force exerted on the second object by the collision includes calculating a force estimated that the particles of the first object are received from the second object at the redefined positions of the particles of the first object. And calculating an acting force exerted on the second object by the collision based on the estimated force.

  The method may further include storing the calculated acting force at a grid point of a grid corresponding to a redefined position of the particle of the first object.

  The first object and the second object may be different from each other.

  The first object may be a fluid, and the second object may be a deformed body.

  According to one embodiment, an apparatus for modeling detects an adjacent region between a first object modeled from a particle and a second object modeled from a particle and defines a grid for the adjacent region. A module and an action force between the first object and the second object in the adjacent area are calculated using information stored at grid points of the grid, and the first object and the first object are calculated based on the action force. An object modeling module for modeling the second object; and a processor for controlling the grid conversion module and the object modeling module.

  The grid conversion module extracts a distance value between an outline of the first object or the second object in the adjacent area and a grid point of the grid adjacent to the outline, and calculates the extracted distance value of the grid. It may be stored at a grid point.

  A determination unit configured to determine whether a collision has occurred between particles of the first object and particles of the second object in the adjacent area; and A detection unit that detects a particle of the first object in which a collision has occurred among particles of the first object and particles of the second object in a region; and a redefinition that redefines a position of the detected particle of the first object. And a calculating unit configured to calculate an acting force exerted on the second object by the collision based on the redefined position of the particles of the first object.

  The redefinition unit may use a distance value and a gradient stored at a grid point corresponding to a cell including the detected particles of the first object to detect particles of the first object that do not penetrate the second object. The moving direction and the shortest moving distance may be calculated, and the position of the particle of the first object may be moved based on the calculated moving direction and the shortest moving distance.

  The calculation unit calculates a force estimated that the particles of the first object are received from the second object at the redefined position of the particles of the first object, and performs the collision based on the estimated force. And calculating the acting force acting on the second object, and storing the calculated acting force at a lattice point of a lattice corresponding to a cell including the particle of the first object in which the collision has occurred.

  An apparatus for modeling an object according to an embodiment includes a memory that stores a program that controls an operation of the modeling apparatus, and one or more processors that drive the program, wherein the program is modeled from particles. Detecting an adjacent area between the first object and the second object modeled from the particles, defining a grid including a plurality of cells for the adjacent area, and extracting information stored at grid points of the grid. And modeling the first object and the second object based on the acting force between the first object and the second object calculated in the adjacent area.

  According to the present invention, the solid state simulation and the fluid state simulation are separated by utilizing the grid for an area adjacent between objects having different characteristics, such as volume preservation required when modeling each solid and fluid. Constraints can be achieved individually.

  According to the present invention, the interaction between the solid and the fluid can be processed in real time by reflecting the information at the time of modeling itself by using the information stored in the background grid by the relative modeling module, and the fluid and the solid mixed with the fluid can be processed. Can be modeled realistically.

FIG. 3 is a diagram illustrating adjacent regions where a method of modeling an object according to an embodiment is used. 4 is a flowchart illustrating a method for modeling an object according to an embodiment. FIG. 6 is a diagram illustrating a method of defining a grid for an adjacent region by a method of modeling an object according to an embodiment. 6 is a flowchart illustrating a method of calculating an acting force between a first object and a second object by a method of modeling an object according to an embodiment. FIG. 4 is a diagram illustrating a method of calculating an acting force between a first object and a second object by a method of modeling an object according to an embodiment. FIG. 1 is a block diagram of an apparatus for modeling an object according to one embodiment. It is a block diagram of a modeling device concerning other embodiments. FIG. 6 illustrates a method of modeling an object according to another embodiment. FIG. 9 is a diagram illustrating a process of processing an adjacent area and an acting force in a modeling device according to another embodiment in an operation order of each module. FIG. 9 is a view illustrating a process of processing an interaction between a fluid and a deformable object via a grid module relay in a modeling device according to another embodiment. 9 is a flowchart illustrating an operation method of the modeling device according to another embodiment. 9 is a flowchart illustrating an operation method of a fluid modeling module in a modeling device according to another embodiment. 9 is a flowchart illustrating an operation method of a deformable object modeling module in a modeling device according to another embodiment. 9 is a flowchart illustrating a method of operating a lattice module in a modeling device according to another embodiment.

  The embodiments described below will be described with reference to the accompanying drawings. The same reference numerals provided in each drawing indicate the same members.

  Various changes may be made to the embodiments described below. The embodiments described below are not intended to limit the embodiments, but should be understood to include all modifications, equivalents, and alternatives thereto.

  The terms used in the embodiments are merely used to describe the specific embodiments, and are not intended to limit the embodiments. The singular expression includes the plural expression unless the context clearly dictates otherwise. As used herein, terms such as "comprising" or "having" are intended to specify the presence of a feature, number, step, act, component, part or combination of those recited in the specification. Shall be understood as not excluding, in advance, the possibility of the presence or addition of one or more other features or numbers, steps, acts, components, parts or combinations thereof. .

  Unless defined differently, it includes technical or scientific terms, and all terms used herein are to be generally understood by those having ordinary knowledge in the technical field to which the embodiments belong. Has the same meaning. Terms commonly used, such as predefined, should be construed as having a meaning consistent with that present in the context of the relevant art, and unless expressly defined in this application, Or is not interpreted as overly formal.

  In the description with reference to the accompanying drawings, the same constituent elements will be denoted by the same reference numerals regardless of the reference numerals, and redundant description thereof will be omitted. In the description of the embodiments, when it is determined that the specific description of the related known technology unnecessarily obscures the gist of the embodiment, the detailed description thereof will be omitted.

  FIG. 1 is a diagram illustrating adjacent regions in which a method for modeling an object according to an embodiment is used. Referring to FIG. 1, a variant (eg, a duck doll) 110 is shown floating in a fluid 130, such as water or oil. Here, the deformable body 110 and the fluid 130 are each modeled by a particle, and hereinafter, the deformable body 110 is used as meaning that the deformable particle is included, and the fluid 130 is meant to include the fluid particle. The “deformable body 110” is understood to mean a rigid body (Rigid body) and a soft body (Soft body). In addition, a certain area including the contours of the deformable body 110 and the fluid 130 is referred to as an “adjacent area” or an “interaction area”.

  In one embodiment, when both the deformed body 110 and the fluid 130 are present, a grid 150 is defined for the adjacent region, and a physical law is applied based on the grid 150, so that the space between the deformed body 110 and the fluid 130 is increased. Ensure that interactions are accurately reflected. The lattice 150 may be a material structure of a mesh having a certain connection relationship, or may be a passage through which the deformable body 110 and the fluid 130 exchange physical quantities between each other. The grid 150 may include a plurality of cells 151, and level set information of the deformable body 110 may be stored as scalar (Scalar) values at grid points of the grid 150. The level set information may be used as a signed distance value on the grid 150 to indicate the position of the deformed body 110 within the grid 150. The level set information indicates whether the grid points of the deformable body 110 are outside or inside based on the contour of the deformable body 110.

  For example, when the deformable body 110 and the fluid 130 collide with each other, the shape of the deformable body 110 may be distorted or the speed may be reduced due to the collision with the fluid 130, and the fluid 130 may be splashed. Here, the fluid 130 flows while avoiding the space occupied by the deformable body 110. The lattice 150 is formed between the deformable body 110 and the fluid 130, such as a collision area between the deformable body 110 and the fluid 130, a region where the fluid 130 is splashed, and a region where the deformable body 110 is distorted and newly occupied in space. Includes all areas where interaction occurs. The above-described interaction may be applied to not only heterogeneous objects such as fluids and deformed objects but also homogenous objects such as water and oil. In one embodiment, the momentum due to the interaction can be precisely stored by calculating the acting force using the grid 150 for the adjacent region including the contour between the objects modeled on the particle basis.

  FIG. 2 is a flowchart illustrating a method of modeling an object according to an embodiment. Referring to FIG. 2, an apparatus for modeling an object according to an embodiment (hereinafter, a modeling apparatus) detects an adjacent region between a first object modeled from a particle and a second object modeled from a particle. (S210). When modeling an object on a particle basis, the modeling device may search for peripheral particles of any one particle. If the searched surrounding particles correspond to different objects having different physical quantities, the modeling device defines an area including any one of the particles and the particle determined as the different object as an adjacent area. The modeling device may detect the adjacent area.

  The modeling device defines a grid for the adjacent area detected in step S210 (S220). For example, the object particles included in the detected adjacent area may be divided into a grid including a plurality of cells. In step S220, the modeling device may extract a vertical distance (value) between the contour of the first object or the second object in the adjacent area and a grid point of a grid adjacent to the contour. The modeling device may store the extracted distance value in a grid point. The distance value stored at the grid point may be referred to as level set information. A specific method of defining a grid in one embodiment will be described with reference to FIG.

  The modeling device calculates the acting force between the first object and the second object in the adjacent area using the information stored at the grid points of the grid (S230). In step S230, the modeling device determines whether a collision has occurred between the particles of the first object and the particles of the second object for each cell of the lattice in the adjacent area. The modeling device calculates an acting force between the particles of the first object and the particles of the second object based on the determination result. Here, the first object may be a fluid, and the second object may be a deformed body. Further, the first object and the second object may be of the same type or different types. In one embodiment, a specific method of calculating the acting force between the first object and the second object will be described with reference to FIGS.

  The modeling device models the first object and the second object based on the acting force calculated in step S230 (S240). In step S240, the modeling device may more accurately correct the shapes or movements of the first object and the second object modeled from the particles using the acting force calculated in step S230.

  FIG. 3 is a diagram illustrating a method of defining a grid for an adjacent region by a method of modeling an object according to an embodiment.

  After detecting (310) an adjacent region 305 between the deformed object 301 modeled from the particle and the fluid 303 modeled from the particle, the modeling apparatus may define a grid 307 for the detected adjacent region 305 or the like. , A grid structure shown in FIG. Due to the lattice formation, for example, one cell may include four particles in the case of 2D, and eight particles may be included in one cell in the case of 3D.

At a grid point 309 of the grid 307, level set information of a distance value to a contour of the deformed object 301 closest to each grid point is stored. For example, the grid point 311 stores d ₁ which is a vertical distance value from the contour of the deformed body 301 to the grid point 311, and the grid point 313 is a vertical distance value from the contour of the deformed body 301 to the grid point 313. there d ₂ is stored. When the distance value stored at the grid point 309 is (+), it indicates that the grid point is outside the deformable body 301, and when the stored distance value is (-), the grid point is deformed. Indicates that it is inside the body 301. Depending on the modeling method, (+) and (-) may be defined oppositely. The modeling device may calculate the inclination based on the level set information, and may convert the level set information into Geometric Normal information as needed.

  At each grid point 309 of the grid 307, apart from the level set information, the acting force of the particles of the fluid 303 received from the deformable body 301 may be calculated by linear interpolation and stored. The stored acting force may be used later to model the particles of the deformable body 301. In addition, the velocity value of the fluid 303 particles is stored in each grid point 309, and the stored velocity value may be used for calculating a drag (Drag Force) received by the fluid 303 particles.

  As described with reference to FIG. 3, the modeling apparatus can check how far the grid point is from the contour of the object and is inside or outside the contour.

  FIG. 4 is a flowchart illustrating a method of calculating an acting force between a first object and a second object by a method of modeling an object according to an embodiment.

  Referring to FIG. 4, the modeling apparatus according to an embodiment determines whether a collision has occurred between particles of a first object and particles of a second object in an adjacent area (S410). In step S410, the modeling device determines whether a collision has occurred using a distance value stored at a grid point adjacent to the position of the particle of the first object. Here, the modeling device determines whether or not a collision has occurred for each cell of the lattice. For example, when the particles of the first object (fluid) and the particles of the second object (deformed body) are overlapped at the same position, in other words, if the fluid particles are at positions penetrating the deformed particles, It is determined that a collision has occurred.

  In addition, in step S410, the modeling device further considers whether the particles of the first object satisfy the volume storage condition. For example, if the first object is a fluid and the second object is a deformed body, the overall volume of the fluid of the first object will be even if the collision causes a change between the first object and the second object. Must be saved. Therefore, in one embodiment, in addition to the distance value stored at the grid point at the time of the collision, it is also considered whether the overall volume of the fluid is kept the same as before the collision.

  If it is determined in step S410 that no collision has occurred, the modeling device skips execution of steps S420 to S440 for collision processing.

  If it is determined in step S410 that a collision has occurred, the modeling device detects a particle of the first object having a collision among particles of the first object and particles of the second object in the adjacent area (S420). Here, the number of particles of the first object where the collision has occurred may be one or more. The modeling device redefines the positions of the particles of the first object detected in step S420 (S430). The modeling device redefines the position of the detected particle of the first object as a position that does not penetrate (the particle of) the second object. For example, if the first object is a fluid and the second object is a deformed body, the fluid particles must flow without penetrating the deformed body (particles) during the collision. Therefore, when a collision occurs between the fluid particles and the deformable particles, the modeling device may perform modeling such that the fluid particles are at positions not penetrating the deformable particles.

  In operation S430, the modeling apparatus may use the distance value and the gradient stored at the grid point corresponding to the cell including the particles of the first object detected in operation S420 to determine whether the particles of the first object do not penetrate the second object. The moving direction and the shortest moving distance are calculated. The modeling device moves the position of the particles of the first object according to the calculated moving direction and the shortest moving distance. Here, the modeling device calculates the moving speed of the particles of the first object using the distance value stored at the grid point and the calculated shortest moving distance, and calculates the particles of the first object that have detected the calculated moving speed. The information may be stored at a grid point corresponding to the included cell.

  The modeling device calculates an acting force exerted on the second object due to the collision based on the redefined positions of the particles of the first object (S440). In step S440, the modeling device calculates a force estimated that the particles of the first object will be received from the second object at the redefined position of the particles of the first object, and based on the estimated force, calculates a second force based on the collision. The acting force exerted on the two objects may be calculated. The modeling device may store the calculated acting force separately at grid points of the grid corresponding to the redefined positions of the particles of the first object.

  FIG. 5 is a diagram illustrating a method of calculating an acting force between a first object and a second object by a method of modeling an object according to an embodiment. In FIG. 5, it can be seen that a sign such as (+) or (-) is displayed at each grid point 510. The modeling device calculates a distance value from the position of the particle of the first object, in other words, the fluid particle to the contour of the deformed object by interpolating the value stored in the grid point. If the sign of the calculated value is (-), it indicates a collision state, and if (+), it indicates a state in which no collision has occurred. In this way, the process of calculating what value the distance value stored at the grid point has at the position of the fluid particle by interpolation is called a “grid value query”.

  The modeling device determines whether a collision between a first object (for example, a fluid) and a second object (for example, a deformed object) has occurred based on a code value stored at each grid point. The modeling device may sample distance values stored at four surrounding grid points at the position of each fluid particle. The modeling device linearly interpolates the values stored at the grid points around each fluid particle to determine the distance between the fluid particle and the particle of the deformed object contour. Here, assuming that the sampled distance value is, for example, +0.5 nm, this means that the center of the fluid particle is 0.5 nm away from the contour of the deformable body. If the radius of the fluid particle is 0.5 nm, the fluid particle is in contact with the contour of the deformed body, and if the radius of the fluid particle is 1.0 nm, the fluid particle is in a state of collision with the deformed body, In other words, it is the position where the fluid particles have penetrated the deformable particles. In such a case, the modeling device processes the collision of the fluid particles by redefining the position of the fluid particles so as not to penetrate the deformable particles.

  For example, when it is detected that the fluid particle is located at the first position 531 corresponding to the inside of the deformed object as indicated by 530 due to the collision between the deformed particle and the fluid particle, the modeling device deforms the fluid particle from the first position 531. It is moved to the second position 533 which does not penetrate the body particles. Here, the modeling device can calculate the moving direction and the shortest moving distance of the fluid particles that do not penetrate the deformable particles, using the distance value and the inclination stored at the grid point corresponding to the cell containing the particles. .

  The modeling device moves the fluid particles to a position where no collision occurs according to the calculated moving direction and the shortest moving distance. For example, the modeling device may determine that a distance value stored at a grid point corresponding to a cell containing a fluid particle has a slope value from (−) to (+) (here, in the horizontal direction, from the right to the left, in the vertical direction). (From top to bottom) so that collisions do not occur between the fluid particles and the deformable particles.

  The modeling device transmits the force corresponding to the amount of impact received by the fluid particles to the deformable body, and reflects the force estimated to have been received by the fluid particles due to the collision between the deformable body and the fluid as the reaction force on the deformable body I do. When the fluid particle moves from the position 550 to the position 533, the force presumed to have been received by the fluid particle may have the same magnitude in the direction corresponding to the deformed body as 551 due to the law of action and reaction. Good. Here, the force estimated to be received by the fluid particle may be calculated using a general physical formula when the initial position and the subsequent position of the fluid particle, the moving speed, and the like are known.

  The deformation may be modeled so that the deformation is raised above the fluid particles by the reaction force acting on the deformation. The modeling device may store the acting force on the deformed object at a grid point of the cell corresponding to the redefined position 533 of the fluid particle. Here, the acting force exerted on the deformed body may be stored differently at each grid point according to the distance from the grid point to the fluid particle. For example, when the distance from the lattice point to the fluid particle is long as in the lattice point 573, the smallest value is assigned. When the distance from the lattice point to the fluid particle is short as in the lattice point 572, for example. May be assigned the largest value. Also, a value larger than the grid point 573 and smaller than the grid point 572 is assigned to the grid points 571 and 574. The acting force assigned to each grid point may be expressed as the length or size of an arrow. At the lattice point 572 where the largest acting force acts, the length or size of the arrow is represented large, and at the lattice point 573 where the smallest acting force acts, the length or size of the arrow is represented small.

  The modeling device may store the acting force exerted on the deformed body in the above-described manner separately at grid points of the cell containing the fluid particle. Through the processes 510 and 530 described above, the modeling device can model the apparent collision between the fluid and the deformed body, and can model the acting force acting between the fluid and the deformed body through the process 550.

  FIG. 6 is a block diagram of an apparatus for modeling an object according to an embodiment. Referring to FIG. 6, a modeling device 600 according to an embodiment includes a grid transformation module 610, an object modeling module 630, and a processor 650.

  The grid conversion module 610 detects an adjacent region between the first object modeled from the particle and the second object modeled from the particle, and defines a grid for the adjacent region. The grid conversion module 610 may extract the distance value between the contour of the first object or the second object in the adjacent area and the grid point of the grid adjacent to the contour, and store the extracted distance value in the grid point of the grid. Good.

  The object modeling module 630 calculates an acting force between the first object and the second object in the adjacent area using the information stored at the lattice points of the lattice, and calculates the first object and the second object based on the acting force. May be modeled. The object modeling module 630 includes a determination unit 631, a detection unit 633, a redefinition unit 635, and a calculation unit 637. The determination unit 631 determines whether a collision has occurred between the particles of the first object and the particles of the second object in the adjacent area. The detection unit 633 detects, based on the determination result of the determination unit 631, the particle of the first object in which the collision has occurred among the particles of the first object and the particles of the second object in the adjacent area. The redefinition unit 635 redefines the positions of the particles of the first object detected by the detection unit 633. The redefinition unit 635 may use the distance value and the inclination stored at the grid point corresponding to the cell including the detected particle of the first object to determine a moving direction of the particle of the first object that does not penetrate the second object. Calculate the shortest moving distance. The redefinition unit 635 moves the positions of the particles of the first object according to the calculated moving direction and the shortest moving distance.

  The calculation unit 637 calculates the acting force exerted on the second object by the collision based on the redefined position of the particles of the first object. The calculating unit 637 calculates a force estimated that the particles of the first object are received from the second object at the redefined positions of the particles of the first object, and generates a collision with the second object based on the estimated force. Calculate the acting force. The calculating unit 637 may store the calculated acting force at a grid point of a grid corresponding to a cell including the particle of the first object where the collision has occurred.

  The processor 650 controls the grid conversion module 610 and the object modeling module 630. The object modeling module 630 according to the embodiment is divided into a module for modeling a deformed object and a module for modeling a fluid, and such an embodiment will be described with reference to FIG.

  FIG. 7 is a block diagram of a modeling device according to another embodiment. Referring to FIG. 7, a modeling device 700 according to another embodiment includes a memory 710, a processor 730, and a communication unit 750.

  The memory 710 stores a program that controls the operation of the apparatus 700 for modeling an object modeled from a particle.

  The processor 730 drives a program stored in the memory 710, and may be one or more. Here, the program detects an adjacent region between the first object modeled from the particle and the second object modeled from the particle, and defines a grid including a plurality of cells for the adjacent region. The program may model the first object and the second object based on the calculated acting force between the first object and the second object in the adjacent area, using information stored at grid points of the grid. .

  The communication unit 750 transmits and receives information necessary for the operation of the apparatus 700 for modeling an object modeled from a particle.

  FIG. 8 is a diagram illustrating a method of modeling an object according to another embodiment. Referring to FIG. 8, a process of obtaining a result of a distribution of interacted particles by performing an operation on an interaction region between the fluid and the deformed body when the particles of the fluid and the deformed body are distributed is illustrated. The calculation for the interaction area is performed as follows.

  The modeling device detects an adjacent region between the fluid and the deformed body (S810), and defines a grid for the adjacent region (S830). The modeling device processes the interaction force between the fluid and the deformed body in the adjacent area using the information stored at the grid points of the grid (S850).

  In one embodiment, the process of processing the interaction force between the fluid and the deformable body is as follows. When a collision occurs between the particles of the first object and the particles of the second object, for example, as described with reference to 510 and 530 shown in FIG. The collision is processed by moving the two objects to positions not penetrating each other (S851). The modeling device processes the acting force acting on the fluid (S853), and processes the acting force acting on the deformed body using the processing result on the fluid (S855). The modeling device processes the acting force acting on the fluid using the fluid modeling module, and processes the acting force acting on the deformed body using the deformed body modeling module.

  FIG. 9 is a diagram illustrating a process of processing an adjacent area and an acting force in a modeling device according to another embodiment in the order of operation of each module. Referring to FIG. 9, a modeling device according to another embodiment includes a time step selecting unit 910, a grid module 920, a deformation modeling module 930, and a fluid modeling module 940.

  The time step selector 910 selects a time step for modeling the interaction between the fluid particles and the deformable particles. For example, assuming that one cycle in which the modeling is performed is one second, the modeling device may perform 0.5 seconds or 0.1 seconds without modeling the interaction between the deformant and the fluid during one second. It may be modeled gradually, such as every three seconds. Here, the time step is a process of determining how many steps are divided into one cycle in units of 0.5 seconds or 0.3 seconds. The time step may be selected to an appropriate value by the time step selecting unit 910 or a user of the modeling device.

  In addition, the time step selecting unit 910 may individually set a time step for the deformable body modeling module 930 and the fluid modeling module 940. The modeling device may select, via the time step selecting unit 910, at what time the movement of the fluid particle or the deformable particle is modeled.

  The grid module 920 receives information from the fluid modeling module 940 according to the time step selected by the time step selecting unit 910. Here, the information received by the grid module 920 from the fluid modeling module 940 may include, for example, an acting force applied to the fluid particles and a final velocity of the fluid particles. Here, the acting force received by the fluid particles may be expressed as a constraint force.

  The lattice module 920 processes the information received from the fluid modeling module 940 and provides the processed information to the deformation modeling module 930. The information processed by the lattice module 920 and provided to the deformation modeling module 930 may be an interaction force between the fluid particles included in the fluid field and the deformation. Here, the interaction force may be understood as an action force of the fluid particles on the deformable body such as a reaction force and a drag force of the fluid particles on the deformable body.

  The deformation modeling module 930 reflects the interaction force received from the lattice module 920 on a shape model for the deformation. The deformation modeling module 930 may generate the shape information of the deformation from the shape model in which the interaction force is reflected. The deformation modeling module 930 may provide the grid module 920 with the shape information of the deformation.

  The lattice module 920 grasps information on the contour of the deformed object from the shape information of the deformed object. The grid module 920 may calculate the acting force of the fluid particles on the deformed body using the shape information. The grid module 920 may send the shape information to the fluid modeling module 940.

  The fluid modeling module 940 uses the shape information to calculate a constraint force applied to the fluid particle due to a collision between the fluid particle and the deformed object and a final velocity of the fluid particle. The fluid modeling module 940 may again provide the constraint force experienced by the fluid particles and the final velocity of the fluid particles to the grid module 920.

  In one embodiment, the relative modeling module (e.g., the deformation modeling module 930 for fluids, the fluid modeling module 940 for deformations) feeds back information stored in the grid module 920, and provides information about its own object particles. By reflecting at the time of modeling, the interaction between the deformed body and the fluid can be processed in real time.

  According to one embodiment, real-time processing of the interaction between the deformed object and the fluid makes real-time the most important, as well as cinematic special effects that require high quality realistic video reproduction. It enables the virtual modeling of fluids and fluid-mixed variants in the field of games and mobile UI.

  FIG. 10 is a diagram illustrating a process of processing an interaction between a fluid and a deformable object via a grid module relay in a modeling apparatus according to another embodiment. Referring to FIG. 10, a fluid modeling module 1010, a grid module 1030, and a variant modeling module 1050 are shown.

  In the modeling step, the fluid modeling module 1010 processes an external force, such as gravity, and models the viscosity of the fluid field, and then updates the positions of the fluid particles. The fluid modeling module 1010 models the fluid particles by determining whether each fluid particle included in the fluid field collides with the deformed object and whether the volume or density of the fluid particles satisfies the volume storage condition. For example, assume that each fluid particle included in the fluid field collides with the deformed body, and that the volume of the fluid particle at the time of the collision satisfies the volume preservation condition. The fluid modeling module 1010 calculates a constraint force applied to the fluid particles and a final velocity of the fluid particles. The fluid modeling module 1010 may, for example, compare the force acting on the fluid particles in the absence of collision and volume conservation conditions to the force acting on the fluid particles in the presence of collision and volume conservation conditions, and receive the fluid particles. The constraint force may be calculated. The fluid modeling module 1010 may provide the grid module 1030 with information regarding the previously calculated constraint forces and the final velocity of the fluid particles.

  The grid module 1030 can help the fluid modeling module 1010 and the deformation modeling module 1050 to implicitly recognize the presence of a counterpart modeling module. The lattice module 1030 may provide the acting force of the fluid particles to the deformation modeling module 1050, and may provide shape information of the deformation to the fluid modeling module 1010. The acting force of the fluid particles may include a reaction force and a drag force of the fluid particles on the deformable body. The lattice module 1030 may calculate the acting force based on the constraining force and the final velocity of the fluid particle when the fluid particle and the deformed body are adjacent within a predetermined distance.

  The lattice module 1030 transmits the shape information of the deformed body to the fluid particles, and transmits the interaction and the resistance received by the fluid to the shape model of the deformed body, so that each of the modeling modules 1010 and 1050 is physically correct. Try to derive interaction results. The grid module 1030 operates on areas where a minimum of fluids and deformations are adjacent so that the interactions are transmitted correctly.

  The deformation modeling module 1050 may model the force generated in the interaction region with the fluid by referring to the lattice module 1030 after modeling the gravitational force, the elastic force, and the like in the same manner as the fluid. In the distance field, the deformation modeling module 1050 applies an acting force to the shape model to determine a final position of the shape model. Here, the acting force takes into account the acting force of the fluid particles on the deformable body, and the acting force may reflect the frictional force and resistance of the fluid particles on the deformed body. The deformation modeling module 1050 considers the collision between the deformation and the fluid particles at the final position of the shape model, and determines the obstacle of the deformation except the shape model and the fluid particles to satisfy the volume preservation condition. Shape information may be generated. The deformation modeling module 1050 generates the shape information of the deformation so that the shape model of the deformation and the obstacle of the deformation satisfy the volume storage condition. Here, the shape model of the deformed body may reflect the acting force of the fluid particles on the deformed body. The deformed body modeling module 1050 may transmit the shape information to the grid module 1030 as, for example, level set information indicating its position at a distance value with a sign on the grid.

  According to an exemplary embodiment, the fluid modeling module 1010 and the deformation modeling module 1050 may be separated to individually achieve constraints such as volume conservation required when modeling particles of the deformation and the fluid.

  Also, in one embodiment, the fluid modeling module 1010 and the deformation modeling module 1050 may perform the fusion processing on the interaction region between the deformation and the fluid by the lattice module 1030 while independently performing each modeling. it can. In the embodiment, virtual lattice formation other than the lattice module 1030 may be used.

  FIG. 11 is a flowchart illustrating an operation method of the modeling device according to another embodiment. Referring to FIG. 11, in the modeling apparatus according to an embodiment, the collision between the fluid particles and the deformable particles included in the fluid field and the volume preservation condition of the fluid particles satisfying the first constraint condition are satisfied. It is determined whether or not it is performed (S1110).

  According to the result of the determination in step S1110, the modeling device calculates the constraint force applied to the fluid particles and the final velocity of the fluid particles (S1120). If the fluid particles and the deformable particles collide, the modeling device moves the fluid particles to a final position that does not penetrate the deformable. The modeling device performs modeling so that the fluid particle satisfies the volume preservation condition at the final position, and then calculates a constraint force applied to the fluid particle and a final velocity of the fluid particle. Further, the modeling device may calculate the constraint force and the final velocity of the fluid particle using the shape information.

  The modeling device calculates the acting force of the fluid particles on the deformable body using the constraint force and the final speed calculated in step S1120 (S1130). The acting force may include a reaction force and a drag force. In step S1130, the modeling device calculates a reaction force of the fluid particles on the deformable body based on the constraint force. Here, the reaction force may be calculated by further using the shape information. The modeling device may calculate the drag of the fluid particle on the deformable body based on the final velocity at the final position of the fluid particle reflecting the constraint force. In addition, the modeling device may determine whether the fluid particles and the deformable particles are adjacent within a predetermined distance, and calculate the acting force according to the determination result.

  The modeling device generates the shape information of the deformed object such that the shape model of the deformed object and the obstacle of the deformed object excluding the fluid particles satisfy the volume storage condition (S1140). The shape model of the deformed body reflects the acting force of the fluid particles on the deformed body. In step S1140, the modeling device applies an acting force to the shape model, and determines a final position of the shape model according to a result of applying the acting force. The modeling device generates shape information of the deformed object such that the obstacle of the shape model and the deformed object satisfies the volume storage condition at the final position of the shape model.

  FIG. 12 is a flowchart illustrating a method of operating a fluid modeling module in a modeling device according to another embodiment. Referring to FIG. 12, the fluid modeling module according to an exemplary embodiment calculates a position of a fluid particle by reflecting an external force that affects the fluid particle in the fluid field and a viscosity of the fluid field (S1210). In operation S1210, the fluid modeling module may calculate a momentum equation between the fluid particles. The fluid modeling module calculates, for example, a momentum storage equation for the first particle in consideration of the second particle adjacent to the first particle, and calculates a density, an external force, and a viscosity for all particles including the first particle and the second particle. May be calculated. The fluid modeling module may calculate a variation that satisfies the incompressibility constraint for each of the first particle and the second particle using the calculation result of the momentum storage equation. The incompressibility constraint refers to the invariant condition of the volume inside the fluid, controls the amount of flow between particles reflecting the particle velocity in a constant fluid field, and increases the contour height due to the interaction between the fluid and the deformed body. Enables precise modeling. The fluid modeling module determines the divergence in the fluid field of each of the fluid particles and allows the divergence to be "0" to satisfy the incompressibility constraint. The fluid modeling module may calculate the position of the fluid particle according to the calculated amount of change.

  Prior to step S1210, the fluid modeling module may initialize particles for modeling a fluid. In the initialization process, the modeling device may initialize information such as a particle amount, a density, a velocity, and a position indicating a fluid in a certain space or region.

  The fluid modeling module determines whether a collision has occurred between the fluid particles included in the fluid field and the deformed body (S1220).

  If it is determined in step S1220 that a collision has occurred, the fluid modeling module moves the position of the fluid particle to a final position that does not penetrate the deformed body (S1230). The fluid modeling module performs modeling such that the fluid particle satisfies a first constraint condition (for example, a volume storage condition) at a final position (S1240). The fluid modeling module calculates a constraint force applied to the fluid particles due to the collision (S1250), and calculates a final velocity of the fluid particles at a final position (S1260). In steps S1250 and S1260, the fluid modeling module may calculate the constraint force and the final velocity of the fluid particles using the shape information of the deformed object received from the grid module. The fluid modeling module provides the grid module with information on the constraint force applied to the fluid particles and the final velocity of the fluid particles (S1270).

  If it is determined in step S1220 that no collision occurs, the fluid modeling module may end the operation or provide the position of the fluid particle calculated in step S1210 to the grid module.

  FIG. 13 is a flowchart illustrating an operation method of a deformable object modeling module in a modeling device according to another embodiment. Referring to FIG. 13, the deformable body modeling module according to an embodiment models a particle-based shape model of the deformable body by reflecting an external force (S1310). The deformation model modeling module reflects the acting force of the fluid particles on the deformation in the shape model modeled in step S1310 (S1320). The deformable body modeling module determines the final position of the shape model according to the application result of the acting force (S1330).

  The deformation modeling module determines whether a collision between the deformation and the fluid particle has occurred (S1340).

  If it is determined in step S1340 that a collision has occurred, the deformation modeling module models the shape model and the obstacle of the deformation so that the second constraint is satisfied at the final position of the shape model (S1350). The deformation modeling module generates shape information for the shape model of the deformation modeled in step S1350 (S1360). The deformed object modeling module transmits the shape information generated in step S1360 to the lattice module (S1370).

  If it is determined in step S1340 that no collision has occurred, the deformable body modeling module generates shape information for the shape model (S1360), and transmits the shape information to the lattice module (S1370).

  FIG. 14 is a flowchart illustrating a method of operating a lattice module in a modeling device according to another embodiment. Referring to FIG. 14, the lattice module according to an embodiment receives shape information of a deformed object from a deformed object modeling module (S1410). The lattice module provides shape information of the deformed object to the fluid modeling module (S1420). The grid module receives from the fluid modeling module the constraining force on the fluid particles and the final velocity of the fluid particles (S1430). The lattice module calculates a reaction force of the fluid particles on the deformable object using the shape information of the deformed object and the constraint force applied to the fluid particles (S1440). The lattice module calculates a drag force of the fluid particle on the deformable body based on the final velocity of the fluid particle at the final position (S1450). The lattice module provides the fluid modeling force including the reaction force and the drag to the deformation modeling module (S1460).

  The devices described above may be implemented with hardware components, software components, and / or combinations of hardware components and software components. For example, a processor, a controller, an arithmetic logical unit (ALU), a digital signal processor (digital signal processor), a microcomputer, a field programmable array (FPA), a programmable logic unit (PLU), a microprocessor, or an instruction (instruction) are executed. It may be implemented using one or more general-purpose or special-purpose computers, such as different devices capable of responding to a request. The processing device may execute an operating system (OS) and one or more software applications running on the operating system. The processing device may also access, store, operate, process and generate data in response to execution of the software. For convenience of understanding, a single processing device may be described as being used, but those of ordinary skill in the art will appreciate that a processing device may include a plurality of processing elements and a plurality of processing elements. It can be seen that it includes multiple types of processing elements. For example, a processing device may include multiple processors or one processor and one controller. Other processing configurations, such as a parallel processor, are also possible.

  The software may comprise a computer program, code, instructions, or a combination of one or more of these, and may configure the processing unit to operate as desired or may independently or cooperatively instruct the processing unit. . Software and / or data, the machine of any type for providing instructions or data to the processing apparatus or is interpreted by the processing device, component, physical devices, virtual devices, computer storage media or device, the signal transmitted Can be permanently or temporarily embodied in waves. The software may be distributed on computer systems connected to a network and stored and executed in a distributed manner. The software and data may be stored on one or more computer readable storage media.

  The method according to the embodiment may be implemented in the form of program instructions capable of executing various processes via various computer means, and may be recorded on a computer-readable recording medium. The computer-readable medium may include one or a combination of program instructions, data files, data structures, and the like. The program instructions recorded on the medium may be specially designed and configured for the purpose of the present invention, and are known and usable by those skilled in the computer software art. You may. Examples of the computer-readable recording medium include a magnetic medium such as a hard disk, a floppy (registered trademark) disk and a magnetic tape, an optical recording medium such as a CD-ROM and a DVD, a magneto-optical medium such as an optical disk, and a ROM. , A RAM device, a specially configured hardware device for storing and executing program instructions, such as a flash memory, etc., may be included. Examples of program instructions include not only machine language codes produced by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like. The hardware device described above may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

  As described above, the present invention has been described with reference to the limited embodiments and the drawings. However, the present invention is not limited to the above embodiments, and any person having ordinary knowledge in the field to which the present invention belongs can be used. Various modifications and variations are possible from such embodiments.

  Therefore, the scope of the present invention is not limited to the disclosed embodiments, but is defined not only by the claims but also by the equivalents of the claims.

700: Modeling device 710: Memory 730: Processor 750: Communication unit

Claims (18)

A method of modeling an object as a simulation by computer graphics, wherein the processor of the modeling computer comprises:
Detecting an adjacent region between a first object modeled from the particle and a second object modeled from the particle;
Defining a grid for the adjacent region;
Calculating an acting force between the first object and the second object in the adjacent area using information stored at grid points of the grid;
Modeling the first object and the second object based on the acting force;
Including
The step of defining the grid comprises:
Extracting a distance value between a contour of the first object or the second object and a grid point of the grid adjacent to the contour in the adjacent area;
Storing the extracted distance value in the grid point;
including,
How to model objects. The step of calculating the acting force includes:
Determining whether a collision has occurred between the particles of the first object and the particles of the second object in the adjacent area;
Calculating an acting force between the particles of the first object and the particles of the second object based on the determination result;
including,
A method for modeling an object according to claim 1. The step of determining whether or not the collision has occurred includes the step of determining whether or not the collision has occurred using a distance value stored at a grid point adjacent to the position of the particle of the first object. ,
A method for modeling an object according to claim 2. The step of determining whether the collision has occurred may further consider whether the particles of the first object satisfy a volume storage condition.
A method for modeling an object according to claim 3. The step of calculating the acting force includes:
Detecting the collision of the first object particles among the particles of the first object and the particles of the second object in the adjacent area, when it is determined that the collision has occurred;
Redefining the position of the particles of the detected first object;
Calculating an acting force exerted on the second object by the collision based on the redefined position of the particles of the first object;
including,
A method for modeling an object according to claim 2 or 3. The step of redefining the positions of the detected particles of the first object includes the step of redefining the positions of the detected particles of the first object so as not to penetrate the second object.
A method for modeling an object according to claim 5. Redefining the position of the detected particles of the first object,
The moving direction and the shortest moving distance of the particles of the first object that do not penetrate the second object using the distance value and the inclination stored at the grid point corresponding to the cell including the detected particles of the first object. Calculating
Moving the position of the particles of the first object according to the calculated moving direction and the shortest moving distance;
including,
A method for modeling an object according to claim 5. Calculating the moving speed of the particles of the first object using the distance value stored at the grid point and the calculated shortest moving distance;
Storing the calculated moving speed at a grid point corresponding to a cell including the detected particles of the first object;
Further comprising,
A method for modeling an object according to claim 7. Calculating the acting force exerted on the second object by the collision;
Calculating a force at which the particles of the first object are estimated to be received from the second object at the redefined positions of the particles of the first object;
Calculating an acting force exerted on the second object by the collision based on the estimated force;
including,
A method for modeling an object according to claim 5. Storing the calculated acting force at a grid point of a grid corresponding to a redefined position of the particles of the first object.
A method for modeling an object according to claim 9. The first object and the second object are different from each other;
A method for modeling an object according to any of the preceding claims. The first object is a fluid, and the second object is a deformed body;
A method for modeling an object according to claim 11.   A computer-readable recording medium on which a program for executing the method according to claim 1 is recorded. A grid conversion module for detecting an adjacent region between the first object modeled from the particle and the second object modeled from the particle, and defining a grid for the adjacent region;
An action force between the first object and the second object in the adjacent area is calculated using information stored at a grid point of the grid, and the first object and the second object are calculated based on the action force. An object modeling module for modeling objects,
A processor that controls the grid conversion module and the object modeling module;
Including
The grid conversion module extracts a distance value between an outline of the first object or the second object in the adjacent area and a grid point of the grid adjacent to the outline, and calculates the extracted distance value of the grid. Store at grid points,
A device for modeling objects. A grid conversion module for detecting an adjacent region between the first object modeled from the particle and the second object modeled from the particle, and defining a grid for the adjacent region;
An action force between the first object and the second object in the adjacent area is calculated using information stored at a grid point of the grid, and the first object and the second object are calculated based on the action force. An object modeling module for modeling objects,
A processor that controls the grid conversion module and the object modeling module;
Including
The object modeling module comprises:
A determining unit that determines whether a collision has occurred between the particles of the first object and the particles of the second object in the adjacent region;
A detection unit configured to detect, based on the determination result, particles of the first object in which the collision has occurred among particles of the first object and particles of the second object in the adjacent region;
A redefinition unit for redefining the positions of the particles of the detected first object;
A calculating unit that calculates an acting force exerted on the second object by the collision based on the redefined position of the particles of the first object;
including,
A device for modeling objects. The redefinition unit may use a distance value and a gradient stored at a grid point corresponding to a cell including the detected particles of the first object to detect particles of the first object that do not penetrate the second object. Calculating a moving direction and a shortest moving distance, and moving the position of the particles of the first object according to the calculated moving direction and the shortest moving distance;
An apparatus for modeling an object according to claim 15 . The calculation unit calculates a force estimated that the particles of the first object are received from the second object at the redefined position of the particles of the first object, and performs the collision based on the estimated force. Calculating the acting force exerted on the second object, and storing the calculated acting force at a grid point of a grid corresponding to a cell including the particle of the first object in which the collision has occurred.
An apparatus for modeling an object according to claim 15. In a device for modeling objects,
A memory for recording a program for controlling the operation of the modeling device,
One or more processors for driving the program;
Including
The program is
Detecting an adjacent region between a first object modeled from particles and a second object modeled from particles, defining a grid including a plurality of cells for the adjacent region, and storing the grid at grid points of the grid Modeling the first object and the second object based on the acting force between the first object and the second object calculated in the adjacent area using the obtained information, and
Extracting a distance value between a contour of the first object or the second object in the adjacent area and a lattice point of the lattice adjacent to the contour, and storing the extracted distance value in a lattice point of the lattice;
A device for modeling objects.