Classifications

• • A—HUMAN NECESSITIES
  • A41—WEARING APPAREL
  • A41H—APPLIANCES OR METHODS FOR MAKING CLOTHES, e.g. FOR DRESS-MAKING OR FOR TAILORING, NOT OTHERWISE PROVIDED FOR
  • A41H3/00—Patterns for cutting-out; Methods of drafting or marking-out such patterns, e.g. on the cloth
  • A41H3/007—Methods of drafting or marking-out patterns using computers

Definitions

• the invention relates to the field of the simulation of the dressing of a mannequin, and finds particular application in the clothing and / or sewing industries.
• the invention describes a method and a device for placing, on a virtual mannequin, a floating garment initially described by its two-dimensional pieces of fabric.
• the problem is to sew the pieces together in a three-dimensional (3D) space and place the garment thus obtained, around the virtual mannequin, in a correct position.
• 3D three-dimensional
• pieces of clothing 2, 4, 6 to be assembled are placed, approximately opposite their final position around a mannequin 8.
• the lines to be sewn are connected by " elastic bands "10, 12, 14, 16, 18, 20, 22.
• the simulation of the tissue is then carried out, in" weightlessness ".
• the pieces come closer to each other and end up stabilizing edge to edge. It only remains to sew.
• a classic garment (a shirt) represents approximately 1.5 m 2 of fabric. With an average mesh size of 1 cm 2 , we obtain a mesh size of this garment of approximately 15,000 elements.
• Each step of the calculation requires the measurement of the forces applying to each element, and therefore at least four measurements of the distance separating it from the neighbors (warp, weft and shears), which. in 3D, represents 12 subtractions, 12 multiplications, and especially 4 extractions of square roots. We are therefore led to make around 60,000 square roots, and 180,000 multiplications, at least, at each time step.
• the complexity of the calculations and the length of the calculation times also penalize any production of the parts by cutting from a fabric or a material.
• the subject of the invention is a method for viewing a garment made up of pieces of clothing on a virtual mannequin, or on a representation of a mannequin or of a mannequin model, or for dressing, with pieces of clothing, a mannequin. virtual or a mannequin model represented in three dimensions, this process comprising:
• the piece of clothing and the dummy model can be represented by data stored in a memory of a computer.
• the parts are first "painted" on the surface of the mannequin, in a contiguous manner, without respecting the geometry or the physical behavior of the fabric.
• the parts are pressed against the dummy.
• the parts are deformed continuously, without tearing or intersection. They are then “sewn", by geometric proximity.
• the compression energy of the tissue is minimized: the tissue is relaxed, or “plumped up”. It goes from a state where this compression energy is important to a state where it is reduced to a value compatible with the position of the garment on the mannequin.
• the 3D shape obtained is then ready for the simulation of draping of the fabric.
• the method according to the invention has a reduced computation time compared to the methods using the simulation of the fabric to carry out the assembly, the sewing and the threading of the garment, while respecting at all times the dimensions and the forces in the fabric.
• the invention avoids the preliminary steps of simulating the fabric, then of bringing the fabric closer to the body or the mannequin. It avoids in particular the calculations of the physical behavior of the fabric, before assembly. It makes it possible to solve the problems of calculation time, by removing the physical constraints linked to the simulation of the fabric and the bringing together of the fabric, and by realizing or simulating the seams directly (junction of the pieces of the garment).
• the method according to the invention makes it possible to temporarily abstain from respecting the geometry (respecting the lengths, the angles of the fabric) so as to keep only the classical continuity relationships in topology: it only implements deformations continuous.
• the invention makes it possible to avoid complex calculations of dilation which involve a deformation of the mannequin: in particular, relaxation implements a deformation of the garment, but not of the mannequin.
• the deposition of the pieces of clothing on the surface of the mannequin involves the establishment of a point-to-point, or bijective and continuous relationship, between the piece, or a part of this piece, or representative points of such a part, and a corresponding portion of the surface of the manikin, or points of such a portion.
• the relaxation step can then include:
• It may also include: - the subdivision of the piece of clothing into a second set of parts, smaller than the parts of the first set,
• the deformations can be chosen so as to respect the topological relationships of the Euclidean volume. The result of this choice is that the calculation of tissue collisions becomes unnecessary.
• Such a deformation can for example comprise: a displacement along field lines coming from the manikin,
• the invention also relates to a method for producing pieces of clothing, comprising:
• the visualization can take place at a place separate from the place of physical production of the pieces of clothing, the data on the displayed pieces of clothing being transferred, after visualization or simulation, to the place of production of the pieces of clothing.
• the invention also relates to a device for implementing the method according to the invention.
• the invention also relates to a device for viewing pieces of clothing on a mannequin, comprising:
• This device may also include means for modifying a selected piece of clothing or for replacing a piece of clothing with another piece of clothing.
• the subject of the invention is also a device for producing pieces of clothing, comprising:
• the means for cutting the pieces of clothing can be controlled by a microcomputer, the data transmission means then connecting the display device and the microcomputer.
• the data transmission means can for example be part of a communication network.
• FIGS. 2 to 6 are examples of steps of applying pieces of clothing to a mannequin, in the context of a method according to the invention;
• FIG. 7 illustrates a step of inserting a homologous line on a mannequin;
• - Figure 8 schematically shows a portion of a mannequin and a tracking system in elliptical coordinates;
• FIGS. 9A and 9B schematically show, respectively, characteristic lines of a part of a mannequin and a part of a mannequin, topologically homologous to a piece of clothing;
• Figure 10 shows the dummy part of Figure 9B, in development in a plane
• FIG. 11 shows a triangulation of a piece of clothing
• FIG. 12 shows steps of a method for pressing a piece of clothing against the mannequin
• FIG. 13 schematically shows an economical process on the move to restore the lengths of a compressed line chain
• FIG. 14 shows steps of a relaxation method according to the invention
• - Figures 15A and 15B show a mesh node surrounded by triangles
• - Figure 16 shows a polygon, in a set of triangles, this polygon containing all the points which see the external contours of all the triangles;
• FIG. 19 shows schematically a general method of mannequin dressing, simulation and analysis of "portability" according to the invention
• FIG. 20 shows the steps of a manikin dressing method according to the invention
• FIGS. 21 A and 21 B represent a device for implementing the invention
• a "computer model” is a computer representation of the volume (or of the useful part of the volume) of a clothing mannequin or of a human body.
• the volume will be assumed to be described by its external surface, itself described as a triangular mesh, the vertices of the triangles of the mesh being points of this external surface.
• Other representations are possible (parametric external surface, or even, volume defined by voxels (small volume elements)).
• the mannequin can therefore be represented by data stored in a memory of a computer or of a computer system, this data corresponding for example to a triangular mesh, or to a parametric external surface, or to these voxels.
• mannequins can be defined, depending on different parameters, for example the age and / or sex of the person the mannequin represents. It is possible to provide various types of mannequin, and to make a selection of a particular type of mannequin.
• a "mannequin" database can be initially defined, in which a user can select a particular mannequin, as required. Such a database can be previously stored in a computer system, as described later in this text.
• the patent US-5 850 222 describes a modeling of a mannequin, usable within the framework of the present invention.
• Garment means the computer representation of two-dimensional (2D) pieces of a garment, by their finish lines and their cut.
• the finish of a room is the set of lines delimiting the visible part of the room once assembled.
• the finish contains the seam lines, the visible hemlines and the fold or clip lines.
• the finish is associated with an implicit notion of interior.
• the part of the fabric outside the finish that is, between the finish and the cut) is called the seam allowance.
• the pieces are supposed to be described with the x axis corresponding to the warp direction of the fabric (the "straight thread"), where they must be cut.
• the garment can therefore be represented by data stored in a memory of a computer or of a system. IT, this data corresponding for example to the finishing and cutting lines.
• various types of clothing can be defined, depending on different parameters, for example the age and / or sex of the person for whom the clothing is intended. It is possible to provide various types of clothing, and to make a selection of a particular type of clothing.
• a "clothing" database can be initially defined, in which a user can select a particular garment, as required. Such a database can also be previously stored in a computer system, as described later in this text.
• a preliminary step of a method according to the invention can therefore consist in the selection and / or visualization of a type of mannequin and of a particular type of clothing.
• a first step of depositing the pieces of clothing on the surface, or against the surface, of the mannequin is carried out. But we do not take into account, for this step, the respect of the geometry or the physical behavior of the fabric. We only take into account the continuity relationships, classic in topology; for example, the deformations are carried out continuously, without tearing or intersection.
• a part 30, called "half-front" is applied to the corresponding surface of the bust 32 of a mannequin. It is possible, in the case of partial pieces, and as illustrated in FIG. 3, to previously merge pieces 34, 36 (or the stored data or the corresponding stored data sets, representative of these pieces) to obtain a piece 30 (or the data representative of such a part) to be applied to part 32 of the dummy.
• Each of the pieces 34, 36 may initially be part of the database used by the maker.
• FIG. 5 represents a part 40 of initially complex shape, comprising the front and rear parts of the same half-part. A cutting allows to isolate the front part 30 which is then applied to the mannequin 32. Again, a corresponding cutting of the data representative of the part 40 is carried out.
• this or this one will be applied, not directly to the initial surface of the mannequin, but to a surface deduced from the mannequin or deduced from the external surface which defines the mannequin. .
• the garment no longer corresponds topologically to the surface of the mannequin 48: the surface of the skirt, once this applied in three dimensions, has two holes 43, 45, while the useful surface of the mannequin (reduced to the legs and the pelvis) has three holes 47, 49, 51.
• the simplest method is to use a manikin that already has this property.
• FIG. 6 represents the application of a skirt panel 44 to a surface 46 deduced from the mannequin 48. The result is equivalent to introducing the two legs into a sheath.
• a point-to-point relationship can be defined between said part and the surface of the mannequin or between the representative data sets, respectively, of the part and the surface of the mannequin. This relation respects the classical continuity relationships of topology.
• each point of the surface of the mannequin or (in the case described above in connection with FIG. 6) of the surface deduced from the mannequin is associated with one and only one point of the garment or piece of garment to be applied.
• the examples given above, in relation to FIGS. 2 to 6 can therefore be described in terms of a one-to-one, or point-to-point, continuous relationship, or in terms of continuous bijection, that is to say of homology.
• FIG. 2 then corresponds to a homology between a half-front piece and the corresponding surface of the mannequin
• FIG. 6 to a homology between a skirt panel and a surface deduced from the mannequin.
• FIG. 5 the fact of cutting the complex part beforehand makes it possible to simplify the calculation of the homology.
• a mesh of the garment or of the 2D part is practiced, or corresponding representative data, capable of supporting the simulation of the fabric, for example a triangular mesh.
• the garment is then topologically complete, sewn and put on the mannequin.
• it is generally extremely compressed and deformed (it can for example be stretched in places) and this in a physically impracticable way. This is normal since the garment is pressed against the mannequin; in fact, as already explained above, the initial steps of the method according to the invention do not take into account respect for the mechanical and / or geometric aspect of the material constituting the garment.
• the result of this "plating" is the same regardless of the length or the size of said piece of clothing.
• the mannequin is first of all separated into different simple parts: - trunk and pelvis
• the part is also cut along a homologous line, as already described above in connection with FIG. 5.
• the parts of the manikin are described in elliptical coordinates.
• the most suitable axis AA ′ is chosen: in the case of the example in FIG. 8 (manikin trunk), an axis passing through the center of symmetry for example is chosen a first section Si (passing through the neck) and on the other hand through the center of symmetry of a second section S 2 , here an abdominal section.
• Each point M is therefore described by a set of coordinates r, p, ⁇ , where r denotes the distance from point M to the center O of the coordinate system, p and ⁇ allow the point M to be located respectively with respect to a horizontal plane and to a vertical reference plane.
• Figure 9B lines defining the left rear arm Figure 9B represents the upper front part of a mannequin, cut along certain characteristic lines.
• This projection is in bijection with the surface (corrected by the maximum radius) of the mannequin.
• a projection is therefore made on a plane of the selected area of the dummy.
• a first bijection is established between the surface (in 3D) of the mannequin (or the data representative of this surface) and its projection on a plane.
• a triangulation is constructed, maintaining the same number of stitches on the parts of the outline sewn with other pieces.
• the deformation algorithm used consists, at each step, in first moving the points of the contour to a new position approaching the desired contour, and this while respecting the constraint of non-inversion of the triangles, while ensuring that the new outline remains a simple polygon, that is to say does not self-intersect.
• triangles there are indeed two possibilities for triangles to be superimposed: by inverting a triangle, or in the case of a complex polygon.
• the initial and final contours are sufficiently similar that it is often unnecessary to respect the "simple polygon" constraint. It suffices that the initial triangulation is reduced, by a scale factor, to be held within its projection. We can then go in a straight line, step by step, from the mesh outline to the corresponding point of the projection. We therefore obtain a reversible projection of each point of the part on a point of the dummy. The data concerning this projection are memorized. In practice, the correspondence of the vertices of the triangles with points of the projection of the dummy is memorized. We also obtain the sewing lines (the corresponding data of which are also stored).
• two bijections are successively carried out: - a first bijection, between the mannequin or a part of it, defined in three dimensions, and a projection of this mannequin or of this part, in two dimensions,
• the layers making up the garment are placed in 3D in successive layers, separated by a thickness small enough to preserve bijectivity. This thickness is related to the minimum radius of curvature of the surface of the manikin.
• the thickness separating two successive layers is chosen to be very small compared to the radius of curvature of said portion of the mannequin, and the sum of the successive thicknesses is less than this same radius of curvature.
• the innermost layer is preferably pressed against the dummy; in other words, the thickness separating this internal layer from the surface of the dummy is zero.
• FIG. 12 summarizes the operations of plating a garment against the mannequin which are in fact carried out on the data representative of the garment parts and of the mannequin.
• a topologically homologous part of the part is isolated from the volume of the manikin. Then (step S28) this part is projected in two dimensions, on a plane.
• step S29 The triangulation of the piece of clothing, obtained before or simultaneously with the preceding operations, is then deformed (step S29).
• the data obtained during these last two steps can be stored.
• the different layers of clothing are then transferred (step S30) against the surface of the mannequin.
• the garment is then ready for relaxation.
• the goal of relaxation is to bring each piece of clothing back to its state of equilibrium. More specifically, the energetic state of the tissue, initially very high due to the topological treatment explained above, is brought back to a value close to the minimum, compatible with the launch of the simulation of the material.
• Different algorithms are possible.
• the comparison of the different characteristics of the fabrics shows that (in general) the dominant energy factor (for any displacement) is the tensile strength.
• the latter is generally at least 100 times greater than the shear strength, and even greater compared to the bending strength, for typical bends. The resistance to bending becomes significant when trying to bend the fabric at a sharp angle.
• the problem can also be treated from large areas, then "descend" to small areas.
• first of all homogeneously “deforms” the whole garment, preferably by looking for a minimum of traction energy (the energy calculation examples are given below).
• the size of a part can be defined according to the number of triangles it contains: thus, the average number of triangles of each part of the first set is chosen larger than the average number of triangles of each part of the set next, and this second number is itself greater than the average number of triangles in each part of a third set ... etc.
• Crumpling is avoided by using "soft" deformations of space, that is to say preferably continuous, derivable and more preferably whose derivative is continuous (function C 2 , from a mathematical point of view) .
• the deformation chosen is a deformation (continuous and differentiable) of space, instead of simply a deformation of the tissue. We therefore move each point as a function of its position in space, and not as a function of its position in relation to its neighbors.
• the deformations can then be chosen so as to respect the topological relationships of the Euclidean volume.
• the result of this choice is that the calculation of the collisions of the fabric becomes useless: the lining can no longer cross the canvas, the sleeve can no longer touch the small side, the garment cannot penetrate the mannequin ... etc.
• the triangulation is preferably chosen sufficiently dense so that the deformation of the space around an elementary triangle can be considered to be linear.
• the calculations are carried out on the data representative of the pieces of clothing.
• the mannequin remains undeformed.
• the traction energy of each part is calculated relative to the initial position of this part, in two dimensions. For example, we calculate, for each triangle of the triangulation of the part considered, the energy variation from the initial position of the triangle, and we then add up the energy variations of all the triangles.
• each triangle we can take, as a measure of energy, the variation of the length of one of its sides or the variation of its perimeter. For each triangle, one can also calculate the energy according to its position in 3D (on the dummy), its rest position in the plane, and a value of the stiffness K of the fabric.
• the Energy function returns the energy value of a triangle // deformed in 3D as a function of its position at an instant t in // 3D, of its rest position in the plane, and of a value of / / stiffness K.
• the units are homogeneous.
• Vba b-> UV [1] - a-> UV [1];
• FIG. 14 represents steps of a relaxation method according to the invention. Again, these steps are performed on the stored garment data.
• a first set of parts is defined according to its size (step 340).
• a deformation function is then chosen for each field line (step S341). This function is optimized as a function of an energy minimization criterion (step S342).
• the energy function has of course been previously defined.
• step S344 a deformation function is again chosen as a function of the field lines, and is optimized.
• the algorithm stops when the operator judges the result satisfactory, or after a predetermined number of iterations (step S343).
• the question of the displacement of a triangular mesh point, without reversal, will now be treated. The problem posed will be explained in conjunction with the figures.
• Respecting the non-reversal constraint therefore consists in testing the direction of rotation of the triangles adjacent to the point to be moved, and, if a reversal is detected (a direction of rotation which reverses), retry a lower displacement (for example half of the initial displacement). In the event of total failure, we can try to unblock the situation by moving the point randomly.
• FIG. 19 is a general diagram of a method according to the invention, of which the operations described above can be part.
• Step S10 the shapes, or subsets of clothing, are defined flat, in two dimensions. During this step, the assembly positions of the different parts can also be defined. This step can be implemented using the software marketed by the Lectra Company under the designation "Modaris”. Step S20 groups the manikin dressing operations, as already described above.
• the pieces of clothing after being selected, are placed against the surface of the mannequin, without taking into account their physical parameters. Then takes place the operation of joining the pieces together, then relaxation.
• a simulation step (S40) can then take place, for example by the finite element method.
• a simulation method that can be used is described by D. Baraff et al. "Large Steps in Cloth
• step S50 the operator can then view the garment, analyze the configuration or the overall impression. If something does not satisfy him (a particular piece of clothing is for example ill-suited to a part of the body), it is possible to select a new piece of clothing replacing the previous one, or else to modify the piece of clothing, for example using the applicant's "Modaris" software.
• the mannequin is again dressed (step S20).
• the process is then repeated from the step where the parts are pressed against the homologous forms of the mannequin and laid flat.
• the relaxation process can then be executed again, and will act on the entire garment to bring it to its position of equilibrium on the mannequin. Thus, account can be taken of all possible interactions between the modified part and all the other pieces of clothing. Otherwise, the manufacturing of the garment (step S60) can take place.
• FIG. 20 is a detailed flowchart representing a dressing method according to the invention.
• a first step (S21) the flat pattern (two-dimensional representation) and the dummy are selected. It can then be checked (step S22) if there is topological compatibility between the type of garment selected and the corresponding part of the mannequin. For example, it can be checked whether the number of holes in the garment corresponds to that of said part of the mannequin. If there is no compatibility, the manikin can be altered (step S23), for example by merging parts of the manikin or by determining an area deduced from the manikin, as already explained above.
• Steps S24 (S241-S244), S25 and S26 are carried out for each couple consisting of a piece of clothing and a surface or part of the mannequin. If one is in the case of a partial part, or of a part comprising a clamp, or of a complex part, one of the following steps can be carried out:
• step S241 fusion of the part with another part - step S242: cutting of complex part
• step S243 insertion of homologous line on the mannequin
• step S27 determines the number of points to be matched with points on the mannequin, as well as the flattening of the corresponding surface of the mannequin (step S28) .
• the contour of the part can then be brought to the contour of the projection of the mannequin (step S29): the mesh is therefore gradually deformed.
• the garment is therefore gradually deformed.
• This step S33 completes the positioning of the garment on the mannequin.
• the garment can then be relaxed (step S34). Then comes the mechanical simulation step (S38), which allows, for a given fabric, to find the right drape, and which eliminates the last deformations. We obtain a realistic image of the garment donned on the mannequin (S39).
• FIGS. 21 A and 21 B An example of a device, illustrated in FIGS. 21 A and 21 B, will now be given, for implementing the method according to the invention.
• This device is generally designated by the reference 119.
• FIG. 21A overall represents a graphics station comprising a microcomputer 120 configured in a suitable manner for the processing, according to a method according to the invention, of models of mannequin and of pieces of clothing, a device 122 of visualization and peripherals of control (for example a keyboard 124 and a mouse 125).
• the microcomputer 120 includes a calculation section with all the electronic components, software or other, necessary for the simulation of the dressing of a mannequin with pieces of clothing.
• the system 120 comprises a programmable processor 126, a memory 128 and a peripheral input, for example a hard disk 132, coupled to a system bus 130.
• the processor can be, for example, a microprocessor, or a processor of central unit or graphics workstation.
• the memory 128 can be, for example, a hard disk, a ROM read-only memory, a compact optical disk, a dynamic random access memory DRAM or any other type of RAM memory, a magnetic or optical storage element, registers or the like. volatile and / or non-volatile memories.
• a mannequin dressing algorithm includes instructions which can be stored in the memory, and which make it possible to dress this mannequin with one or more pieces of clothing, in accordance with any one of the embodiments of the present invention.
• a program for implementing the method according to the invention is resident or recorded on a medium (for example: floppy disk or CD ROM or removable hard disk or magnetic medium) capable of being read by a computer system or by the microcomputer 120.
• This program concerns a process for dressing, with pieces of clothing, a mannequin represented in three dimensions. It includes instructions for:
• the microcomputer can comprise calculation means, for calculating for example the projections of the selected parts of the manikin, or also for calculating values of the potential field lines, if these are not already associated beforehand with the selected manikin, or to perform triangulations and their deformations, and / or the operations of applying the garment to the mannequin. These calculation means also make it possible to carry out the energy calculations (traction energy) and the calculations for minimizing these energies during relaxation.
• the microcomputer 120 can be programmed to generate mannequin shapes, or such shapes can be stored beforehand, for example in memory 128. Likewise, shapes of pieces of clothing can also be stored beforehand. In this case, means are provided which make it possible to select a mannequin and one or more pieces of clothing. These elements may have been obtained by CAD or by automatic generation systems.
• the microcomputer 120 can also be connected to other peripheral devices, such as for example, printing devices 132. It can be connected to an electronic network, for example of the Internet or Intranet type, making it possible to send messages. data relating to mannequins and / or clothing.
• the operator can then view the garment, analyze the configuration or the overall impression, and if something does not satisfy him, he can select a new piece of clothing replacing the previous one, or modify a piece of clothing.
• FIG. 22 Such a device is illustrated in FIG. 22. It comprises means 136 of the cutting table type, on which sheets 138 of material to be cut, for example fabric, can be positioned, means 140 for positioning and moving a cutting tool 150 above this table, and means 142 for piloting or controlling these positioning and cutting means.
• the steering means are IT means. They may also include means 144 for viewing the piece to be cut, the data of which has been transmitted and / or means for viewing the area of the piece positioned on the cutting table.

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• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Processing Or Creating Images (AREA)
• Professional, Industrial, Or Sporting Protective Garments (AREA)
• Details Of Garments (AREA)
• Toys (AREA)
• Grinding-Machine Dressing And Accessory Apparatuses (AREA)

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• 1999
  • 1999-10-08 FR FR9912563A patent/FR2799556B1/fr not_active Expired - Fee Related
• 2000
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  • 2000-10-09 US US09/857,685 patent/US6968297B1/en not_active Expired - Lifetime
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