JPH1027263A - Three-dimensional simulation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a three-dimensinal(3D) simulation method capable of shortening plotting processing time by using the retrieval of primitive graphics for the attainment of various 3D simulation functions. SOLUTION: Information defining circumscribed rectangular parallelopiped C including all primitive graphics A, B constituting each equipment/installation is prepared in each equipment/installation and the primitive graphics of the equipment/installation included within a vidual field are collectively retrieved as a group of the equipment/installation unit by using the prepared information, so that the quantity of retrieving processing can be reduced. Since the simplification of a shape and the retrieval/ non-plotting of an unvisible equipment can be executed by using the information of the circumscribed rectangular parallelopiped C, the number of polygons to be plotted can be reduced and plotting processing time can be shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a three-dimensional simulation method using computer graphics.

[0002]

2. Description of the Related Art With the improvement of computer processing performance,
Various three-dimensional simulation systems using computer graphics have begun to be applied.

In a three-dimensional simulation system, a real or imaginary object is modeled (three-dimensional CA).
D) and placed on a simulation space (virtual space). Further, by setting a viewpoint of a camera or the like in the simulation space, an object in the simulation space viewed from the viewpoint is displayed on a screen of a computer. If you are looking at the display,
You can simulate the model as if you were looking at reality.

In recent years, three-dimensional simulations have begun to be applied to plants for electric power and water treatment. In a three-dimensional simulation for a plant, a three-dimensional model of each device (including equipment) in the plant is represented as a set of primitive figures such as a rectangular parallelepiped and a cylinder. When the three-dimensional simulation is used for a plant operation, the following functions are realized.

(1) Walk-through function.

A virtual camera (viewpoint) freely moves around the inside of the plant model (camera moving function), and an image viewed from the camera is displayed on a computer display using computer graphics (drawing). function.

(2) A pass-through inhibiting function.

A function that prevents the camera from entering or passing through the device. Usually, a primitive figure that forms a three-dimensional model of a device is composed of only surfaces and has no solid content. Therefore, the camera does not hit the primitive figure and enters the device.

(3) Danger warning function.

[0010] A function that sounds an alarm when a camera approaches a dangerous device when approaching the devices in the plant. A dangerous area is set in advance, and the area between the surface of the primitive graphic and the dangerous area is defined as a dangerous area.

(4) Automatic lifting function.

If there is a device such as a staircase in a plant that changes the height of the viewpoint, a function to automatically change the height of the camera just by moving forward without being conscious.

(5) Animation function.

A function of automatically changing camera parameters (three-dimensional position and orientation in a simulation space) as set. In the walk-through, the operator changes the parameters of the camera.

[0015]

At present, the function of the three-dimensional simulation system for a plant is to retrieve a primitive figure (a group of processing candidate primitive figures) which satisfies almost all the conditions for realizing the function, and to search for the processing candidate. Processing is performed on a group of primitive figures.

For example, the drawing function searches for a primitive figure in the field of view of the camera from all the primitive figures, and draws a processing candidate primitive figure as a search result.

The pass-through prohibition function searches for a primitive graphic inside the camera from all primitive figures, and performs a pass-through prohibition process on the processing candidate primitive graphic as a search result.

The search for these processing candidate primitives is performed on all primitive figures regardless of whether the number of candidate primitives is large or small. In extreme cases, the number of candidates is 0
But you have to search all primitives.

Therefore, when the number of primitives constituting one device is large, such as in a three-dimensional simulation for primitives, the processing amount is enormous.

An object of the present invention is to provide a three-dimensional simulation method capable of reducing the amount of processing for searching for primitive figures for realizing various three-dimensional simulation functions.

Next, in the plant simulation system, the drawing processing time is an important factor so as to affect the overall performance. The rendering processing time is the time from when the viewpoint placed in the simulation space changes to when the object in the simulation space viewed from that viewpoint is displayed on the computer display. Processing such as drawing on the memory of the computer → drawing on the display is required. In order to realize comfortable interactive performance in the simulation system, the shorter the drawing processing time, the better.

However, in the conventional simulation system, a device in the field of view is searched (generally called a clipping process), and only the devices in the field of view are drawn to reduce the drawing time. However, basically all the devices in the field of view are drawn. Therefore, even if the drawing target devices are narrowed down by the clipping process, if the number of primitives (or the number of polygons) constituting each of the devices is large, the drawing time increases as a result, and comfortable interactivity cannot be secured. .

FIG. 4 shows an example of the number of polygons to be drawn (polygons that are present in the field of view and need to be drawn) in the actual simulation system and the measurement results during the drawing process. It can be observed that the drawing processing time increases as the number of drawing target polygons increases. Since the drawing time exceeds one second for several thousand polygons, the interactivity is considerably impaired.

It is another object of the present invention to provide a three-dimensional simulation method capable of shortening a drawing processing time by searching for a primitive figure for realizing various three-dimensional simulation functions.

[0025]

[Means for Solving the Problems]

(First Invention) The present invention forms a three-dimensional model of plant equipment and facilities as a set of primitive figures, searches for primitive figures within a range seen from a viewpoint, and draws on a display with various functions. In a three-dimensional simulation system, information defining a circumscribed rectangular parallelepiped including all the primitive figures constituting them is prepared for each of the devices / equipment individually, and a list of the respective devices / equipment is provided from the viewpoint. A device / equipment included in the circumscribed rectangular parallelepiped or its surroundings, which is included in the range seen, is searched for as an equipment / equipment candidate list, and a primitive figure of the equipment / equipment included in this list is searched as a primitive candidate list. It is characterized in that various functional processes of the three-dimensional simulation are performed on the primitive candidate list.

That is, information on a minimum rectangular parallelepiped circumscribing a three-dimensional model of equipment / equipment is prepared, and using this information, primitive figures of the equipment / equipment in the field of view are grouped as a group of equipment / equipment units. By searching,
Reduce the amount of search processing.

(Second Invention) The present invention is characterized in that equipment / equipment whose distance from the viewpoint to the equipment / equipment is greater than or equal to a set value draws a primitive figure in a simplified manner.

The drawing of the primitive figure is characterized by using a circumscribed rectangular parallelepiped of the primitive figure.

That is, for equipment / equipment whose distance from the viewpoint is equal to or larger than the set value, all primitives constituting the equipment / apparatus are approximated by a circumscribed rectangular parallelepiped or the like, and a simplified drawing is obtained.
Reduce the number of polygons to shorten the rendering processing time.

(Third invention) According to the present invention, a primitive of a large volume of equipment / equipment among the equipment / equipment is registered in advance, and when the registered equipment / equipment falls within the field of view, the primitive is registered. It is characterized by searching for a device / equipment hidden behind a primitive, and removing the device / device from the drawing target device.

That is, the drawing processing time is shortened by omitting drawing of equipment / equipment hidden behind equipment / equipment having a large volume.

(Fourth Invention) The present invention is characterized in that, in drawing a primitive figure, primitives having a small volume value are reduced from a plurality of primitives constituting equipment / equipment to be drawn.

That is, a primitive with a large volume value is more easily perceived than a primitive with a small volume value.
By performing the drawing process in which primitives having a small volume value are reduced, the drawing process time is reduced.

It is to be noted that the magnitude of the volume value is determined according to the relative distance from the viewpoint, and that the model is deleted at a level of simplification that is determined step by step from the outline to the detail.
The total number N of primitives to be drawn can be set in advance.

[0035]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) FIG. 1 shows an example of a primitive expression of a three-dimensional model of a device, showing two primitive figures A and B.
Is represented as an aggregate of For this primitive expression, in the present embodiment, a rectangular box circumscribing the three-dimensional model is defined, and information on the circumscribed rectangular box is used to speed up various function processing.

The definition of the circumscribed cuboid of the device will be described. Generally, in a three-dimensional simulation system for a plant, a three-dimensional model of one device (for example, a transformer) is a three-dimensional (x,
(y, z) space is modeled above. FIG. 1 shows an example of expressing primitive figures A and B.

In this expression, the circumscribed rectangular parallelepiped of the device means that all the surfaces are xy, yz,
A rectangular parallelepiped parallel to the zx plane and containing all primitives constituting the device is assumed to have the smallest size. FIG. 2 shows an example in which a circumscribed cuboid C is defined for the aggregate of FIG.

As described above, by defining one circumscribed cuboid for one set of devices, the circumscribed cuboid can be used as information on the approximate position and size of the set of devices in the three-dimensional space. (Grouping).

Hereinafter, embodiments according to various functions will be described. In the three-dimensional simulation for a plant, all the devices constituting the plant are individually converted into data in the form of a list. When performing some processing, a list of primitives to be processed (referred to as a primitive candidate list) is created, and processing is performed using the list.

(1) Drawing: To search for a primitive figure in the visual field and draw on the display, the following 2
Search by stage.

(1a) From all device lists, search for a device in which the circumscribed cuboid is in the field of view, and if so, add it to the drawing device candidate list.

(1b) Search for primitives in the field of view from the drawing device candidate list, and if so, add them to the primitive candidate list.

Drawing is performed using the primitive candidate list created by the above processing.

(2) Prohibition of passing through: The camera searches for primitives inside the camera in the following two stages and performs a process of prohibiting passing through.

(2a) The camera searches for a device inside the circumscribed rectangular parallelepiped from all the device lists, and adds a device inside the device to the device candidate list.

(2b) From the device candidate list, the camera searches for primitives inside the camera and adds those inside the camera to the primitive candidate list.

The pass-through prohibition process is performed using the primitive candidate list created by the above process.

(3) Danger alarm: The camera searches for primitives within the danger alarm range (external shape and danger range) in the following two stages and performs danger alarm processing.

(3a) From all the device lists, the camera searches for devices within the danger alarm range, and those inside are added to the device candidate list.

(3b) From the device candidate list, the camera searches for primitives that are within the danger warning range, and those inside are added to the primitive candidate list.

By the above processing, the danger warning processing is performed using the created primitive candidate list.

(4) Automatic elevation (automatic change of height of visual field)
... The primitive on which the camera is mounted is searched for in the following two stages, and the automatic ascent / descent process is performed.

(4a) The camera searches for a device inside or above the circumscribed cuboid from all device lists, and adds a device inside or above the circumscribed cuboid to the device candidate list.

(4b) From the device candidate list, search for a primitive whose camera is at the top, and add it to the primitive candidate list if it is at the top.

Automatic elevation processing is performed using the primitive candidate list created by the above processing.

The fact that the processing amount is reduced in the three-dimensional simulation using the circumscribed cuboid in each of the above processes will be described below.

For simplicity, it is assumed that the plant has E (E ≧ 1) devices, and each device is composed of P (P ≧ 1) primitive figures. In addition, the same algorithm is used for the circumscribed cuboid of the device and for the primitive, and the amount of processing for searching for a primitive candidate from the entire device list is considered.

In the case of the conventional method, since all the primitives are searched, the processing amount C is C = EP. On the other hand, in the case of the present embodiment, first, all devices are searched, and primitives are searched for all n (E ≧ n ≧ 0) device candidates among them. Therefore, the processing amount M is M = E + nP. Become.

Therefore, the processing amount ratio R (M / C) is R = n
/ E + 1 / P, which indicates that the processing amount linearly increases and decreases depending on the value of n. This ratio R is R <1
, That is, when the value of n is 0 ≦ n <E (1-1 / P), the processing amount is reduced in the present embodiment. When n = 0, it is reduced most and becomes 1 / P.

In the actual simulation of the plant, since P is about several tens, an approximation of E (1-1 / P) ≒ E holds. That is, in practice, the processing amount is reduced by the method of the present embodiment for all values of n, and at most 1 / P
To be reduced.

(Second Embodiment) In the present embodiment, a drawing processing time is shortened by using a circumscribed cuboid of a three-dimensional model. The number of polygons to be drawn is determined by using circumscribed cuboid information of a device to be drawn. By eliminating, the drawing processing time is shortened.

As described in the above embodiment, in the three-dimensional simulation system for a plant, the three-dimensional model of one device is a three-dimensional (xyz) space as an aggregate of several primitive figures. The circumscribed cuboid of the device is the model that is expressed on the simulation space, and the surface is all parallel to the xy, yz, and zx planes, and the smallest cuboid that contains all the primitives that constitute the device. It is.

By defining one circumscribed cuboid for one device, the circumscribed cuboid has information on the approximate position and size of the device in the three-dimensional space. A circumscribed cuboid can be defined for each primitive constituting the device.

By the way, even if a device far away from the viewpoint is drawn in detail, the details cannot be perceived by human eyes.

Therefore, in the present embodiment, in the drawing processing, a certain threshold distance dt is set, and a device whose distance from the viewpoint is smaller than dt draws the model as it is. A device whose distance from the viewpoint is greater than or equal to dt determines that even if the model is drawn as it is, humans cannot perceive the details, and renders the device with a simplified shape (reducing the number of drawn polygons). A specific simplified shape utilizes a circumscribed cuboid of primitives constituting the device.

In other words, in the present embodiment, a device whose distance from the viewpoint is dt or more draws all primitives constituting the device by approximating it with a circumscribed cuboid. When a circumscribed rectangular parallelepiped is used, the shape of the square prism is not simplified because the actual shape is the same as that of the circumscribed rectangular parallelepiped (the number of polygons is not reduced). On the other hand, a cylinder (represented by a polygon such as a dodecagonal prism in the simulation) can reduce the number of polygons by drawing a circumscribed rectangular parallelepiped.

When the model includes many cylinders as in a plant simulation, the effect of reducing the drawing time by simplifying the shape with a circumscribed rectangular parallelepiped becomes large. FIG.
As can be seen from the comparison of the actual processing time, according to the present embodiment, it can be seen that the drawing processing time is reduced.

(Third Embodiment) In a system such as a three-dimensional simulation for a plant, there are many cases where a device having a large volume (for example, a transformer in a substation) is arranged. When such a large device is in the field of view, the device behind it and completely hidden by the large device is originally a device that cannot be seen through the display, so there is no need to draw.

Therefore, in the present embodiment, a large primitive of a device having a large volume (including a large rectangular parallelepiped or a cylinder) is registered in advance, and when the device enters the field of view, a large primitive is placed behind the primitive. Search for a device that has been completely hidden, and remove the device from the drawing target device.

More specifically, first, when a large primitive of the set device enters the field of view, a plurality of planes passing through the outer edge (edge) of the circumscribed rectangular parallelepiped of the primitive and the viewpoint are obtained, and the plane is closed with the plane. Space (the space covered by the set primitive). Next, it is determined whether or not the primitive is in the space covered by the primitive based on the circumscribed rectangular parallelepiped of the device behind the primitive, and is removed from the device to be drawn if it is in the space.

As a result, in the present embodiment, drawing of a device hidden behind a large volume device can be omitted, and the drawing processing time can be shortened.

(Fourth Embodiment) In the above-described second embodiment, when the distance from the viewpoint to the device / equipment is equal to or more than the set value, the primitive figure is simplified for drawing, and the drawing time is reduced. Shorten.

For this purpose, a simplified model is created in advance, and the three-dimensional simulation holds all of the data. For example, when simplifying the shape of an object, if the simplification level is set to five levels, it is necessary to create four simplified models in addition to the original three-dimensional model. It takes time and effort. Further, since all of the five created models are held by the simulation system, the memory usage of the system is increased as compared with the case of one three-dimensional model.

In order to solve such a problem, in the present embodiment, the shape is simplified by reducing primitives having a small volume value from a plurality of primitives constituting equipment / equipment to be drawn, and the drawing processing time is reduced. To shorten the time.

That is, when a primitive having a large volume value and a primitive having a small volume value are projected on a computer display, primitives having a large volume value are more easily perceived than primitives having a small volume value, and thus primitives having a small volume value are reduced. By performing the drawing process described above, the processing time is reduced.

More specifically, in order to render primitives in descending order of volume value, the primitive shapes forming each three-dimensional model are arranged in descending order of volume value, and the number of primitives to be rendered is determined according to the distance between the viewpoint and the model. By limiting, the shape is simplified. The algorithm of the present embodiment is described below.

(1) Advance preparation (1a) The number N of primitive shapes to be drawn is determined.

(1b) For each three-dimensional model, the primitive shapes constituting the three-dimensional model are arranged in descending order of volume value.

(2) Change of viewpoint (2a) A three-dimensional model within the visual field is searched, and a list of objects to be drawn is created.

(2b) Each object 0 to be drawn
_{i (i} = _0~l, -1) to calculate the distance d _i between the viewpoint and.

(2c) The number n _{i of} primitive shapes to be drawn of the object 0 _i to be drawn is calculated by the following equation.

[0082]

N _i = D _i × N / ＝ D _j where D _i = 1 / d _{i In} this calculation, if n _i is larger than the total number p _{i of} primitive shapes constituting object 0 _i , n _i = p _i
And If n _i <pi, shape simplification is performed.

(2d) For the object 0 _i to be drawn, only n _i primitive shapes are drawn.

According to the present embodiment, there are the following advantages.

(A) Total number N of primitive shapes to be drawn
Is set in advance, a minimum frame rate (the number of drawing updates per second) can be secured.

(B) Since the shape of each three-dimensional model is simplified in descending order of the volume value of the primitive shape, it is possible to realize a stepwise setting of the simplification level from the outline to the detail.

(C) There is no need to create a simplified model in advance, and there is no need to have a separate simplified model, so there is no extra memory consumption.

(D) Shape simplification according to the relative distance, not the simplification of the shape based on the absolute distance from the viewpoint as in the related art. The image distortion is small because the image level can be set.

FIG. 5 shows the relationship between the number of drawing polygons and the frame rate in an actual three-dimensional simulation system, with and without the present embodiment.

In the actual measurement result, the number N of primitive shapes to be drawn is set to 1000 (the minimum frame rate is 1) as an example. From FIG. 5, it can be seen that the frame rate is improved to about four times by applying the present embodiment.

FIG. 5 also shows the distortion rate of the image when the shape is simplified. Here, the image distortion rate refers to the distortion of a drawn image according to the present embodiment (with shape simplification) compared to the conventional method (without shape simplification) when a certain scene is drawn in a display window of 640 pixels × 480 pixels. The ratio was determined by the following equation.

[0092]

## EQU2 ## Distortion ratio (%) = Σ (T _ij ≠ M _ij ) / total number of pixels (640 pixels × 480 pixels) × 100 where T _{ij is} the color value of (i, j) pixel drawn by the conventional method .

M _ij : (i,
j) Color value of the pixel.

From this result, it can be said that the smaller the distortion rate is, the smaller the deterioration of the image quality due to the simplification of the shape is. Referring to FIG. 5, since the distortion rate is not more than ぽ 6%, it can be seen that the shape is simplified without deteriorating the original image quality.

[0095]

As described above, according to the present invention, devices and
Conventionally, information on the smallest cuboid circumscribing the 3D model of equipment is prepared, and this information is used to collectively search for primitive figures of equipment and equipment in the field of view as a group of equipment and equipment units. It is possible to reduce the amount of search processing as compared with the search for individual primitives.
Specifically, the following effects are obtained.

(1) The amount of processing for searching for a primitive figure to be drawn for realizing the drawing function can be reduced on average.

(2) The average amount of processing required for the camera to search for a primitive figure inside the camera for implementing the pass-through inhibiting function can be reduced.

(3) The average amount of processing required for the camera to search for a primitive figure within the shape + danger range to realize the danger warning function can be reduced.

(4) The average amount of processing for retrieving a primitive figure on which the camera is placed for realizing the automatic elevation function of the camera can be reduced.

Further, according to the present invention, the simplification of the shape, the search for the invisible device, and the non-drawing are performed by using the circumscribed rectangular parallelepiped information of the three-dimensional model. Has the effect of reducing the drawing processing time.

Further, according to the present invention, primitive figure drawing has the following effects because a primitive having a small volume value is reduced from a plurality of primitives constituting equipment / equipment to be drawn.

(A) The rendering processing time can be shortened by the rendering processing in which primitives having a small volume value are reduced while the primitives having a large volume value are easily perceived.

(B) There is no need to create a simplified model in advance, and there is no need to have a separate simplified model, so there is no extra memory consumption.

(C) Total number N of primitive shapes to be drawn
Is set in advance, a minimum frame rate (the number of drawing updates per second) can be secured.

(D) By simplifying the shape of each three-dimensional model in ascending order of the volume value of the primitive shape, a simplification level of the model from outline to detail can be realized.

(E) The shape simplification according to the relative distance is performed instead of the shape simplification based on the absolute distance from the viewpoint as in the related art. Since the simplification level can be set, image distortion is small.

[Brief description of the drawings]

FIG. 1 is an example of a primitive expression of a device model.

FIG. 2 is a definition example of a circumscribed cuboid according to the embodiment of the present invention.

FIG. 3 is a comparison result of drawing processing time between a case where the method of the present invention is applied and a conventional method.

FIG. 4 shows measured values of drawing processing speed in a three-dimensional simulation for a plant.

FIG. 5 shows frame rate and distortion rate characteristics when the method of the present invention is applied and a conventional method.

Claims (5)

[Claims] 1. A three-dimensional simulation system that forms a three-dimensional model of plant equipment / equipment as a set of primitive figures, retrieves a primitive figure group within a range viewed from a viewpoint, and draws on a display with various functions. In each of the devices and equipment individually, prepare information that defines a circumscribed cuboid containing all the primitive figures constituting them, and within a range viewed from the viewpoint from the list of the devices and equipment. The device / equipment included in the circumscribed cuboid or its surroundings to be entered is searched for as an equipment / equipment candidate list, and the primitive figure of the equipment / equipment included in this list is searched for as a primitive candidate list, and for this primitive candidate list, -Dimensional simulation method characterized by performing various functional processes of a three-dimensional simulation by using 2. The device / equipment according to claim 1, wherein the device / equipment whose distance from the viewpoint to the device / equipment is equal to or more than a set value renders a primitive graphic in a simplified manner.
Dimension simulation method. 3. The three-dimensional simulation method according to claim 2, wherein the drawing of the primitive figure is a circumscribed rectangular parallelepiped of the primitive figure. 4. The three-dimensional drawing according to claim 2, wherein the drawing of the primitive figure is performed by reducing a primitive having a small volume value from a plurality of primitives constituting a device / equipment to be drawn. Simulation method. 5. A primitive for a device / equipment which is large in volume among the devices / equipment is registered in advance, and when the registered equipment / equipment enters the field of view, the equipment is hidden behind the primitive.・ Search for equipment,
The three-dimensional simulation method according to claim 1, wherein the device is removed from a drawing target device.