JPH0738231B2 - Object deformation display device - Google Patents

Description

The present invention relates to an object deformation display method and apparatus for deforming and displaying a basic shape of an object by a deformation command.

(Prior Art) In many conventional object deformation display devices, an object is approximated by a polyhedron and displayed. Then, when the object is deformed, all the vertices of the polyhedron are moved by the linear transformation of the vertex coordinates, only one vertex of the polyhedron is moved, the predetermined feature points are moved, and the vertices in between are moved. Three methods are adopted: moving according to the movement of feature points. Note that one example of the method is the literature
1: The 2nd Nicograph Thesis Contest Proceedings, written by Takaaki Akimoto, in the paper "Generating Facial Images with Facial Expressions and Movements by Automatic Deformation of Chin and 3D Model of Chin".

Further, in a conventional object deformation display device, a free-form surface may be used to display an object. In this case, a free-form surface is generated with the vertices of a polyhedron approximating the object as a control point, and the free-form surface is displayed to perform smooth object display.

(Problems to be Solved by the Invention) In the conventional method, since all the vertices of the polyhedron move, there is a problem that only simple deformation operations such as enlargement, reduction, and rotation can be performed.

In addition, in the conventional method, since an arbitrary deforming operation can be performed by moving one point at a time, there is a problem that the amount of work required for that operation becomes enormous.

Further, the conventional method has a problem that arbitrary deformation cannot be performed because the characteristic points are predetermined.

Further, also in the conventional object deformation display device using the free-form surface, any one of these methods is used to move the control point. Therefore, there is a similar problem regarding the deformation of the object.

It is an object of the present invention to provide an object deformation display method and device that can easily define and execute arbitrary deformation by setting rules for deformation.

(Means for Solving Problems) In the object deformation display method of the present invention, a shape represented by a plurality of control points for generating a free-form surface is displayed in order to display the object shape after being deformed by a deformation command. Is a basic shape of the object, the deformation rules corresponding to the plurality of deformation commands for deforming the basic shape are described, and one of the plurality of deformation commands and a parameter required by the deformation command are described. Is specified, the control point to be moved is selected from the plurality of control points according to the transformation rule corresponding to this transformation command and the above-mentioned parameter, and is moved to transform the basic shape to generate a transformed shape. Then, a free-form surface is generated based on the deformed shape to generate a display shape, and the display shape is displayed.

In addition, the object deformation display device of the present invention uses the shape represented by a plurality of control points for generating a free-form surface as the basic shape of the object, in order to display the object shape after being deformed by the deformation command. A basic shape storage unit for storing, a deformation rule storage unit for storing deformation rules corresponding to a plurality of deformation commands for deforming the basic shape, a deformation command for one of the plurality of deformation commands, and the deformation thereof. A designation section for designating a parameter required by the command and a modification rule corresponding to the modification command should be read from the modification rule storage section and moved from the plurality of control points according to the modification rule and the parameter. A deformed shape generation unit that deforms the basic shape by selecting and moving control points to generate a deformed shape, and a free-form surface based on this deformed shape A display shape generation unit that generates a display form is generated, and a display unit for displaying the display shape.

(Operation) The object deformation display method of the present invention will be described.

In order to deform and display the shape of an object with a deformation command, a shape represented by a plurality of control points for generating a free-form surface is defined as a basic shape of the object. Further, a plurality of transformation commands for transforming the basic shape are also defined, and transformation rules corresponding to the respective transformation commands are described.

Then, when the object is deformed and displayed, one of the plurality of modification commands and a parameter required by the modification command are designated. A control point to be moved is selected from a plurality of control points forming the basic shape of the object according to the deformation rule and the parameter corresponding to this deformation command. Also, these selected control points are also moved according to the deformation rules and parameters. In this way, the basic shape is deformed, and the deformed shape as the deformation of the basic shape is generated.

Further, a free-form surface is generated based on this deformed shape to generate a display shape.

Finally, this display shape is displayed to display the deformed object.

Next, the object deformation display device of the present invention will be described.

First, a shape represented by a plurality of control points for generating a free-form surface is defined as a basic shape, and this is stored in the basic shape storage unit. Also, define the transformation rules respectively corresponding to the transformation commands to transform the basic shape,
It is stored in the transformation rule storage unit.

Then, when the object is deformed and displayed, the specification unit is operated to specify one of the plurality of modification commands and the parameter required by the modification command. The deformed shape generation unit that receives this deformation command reads out the deformation rule corresponding to the specified deformation command from the deformation rule storage unit. Then, a control point to be moved is selected from a plurality of control points forming the basic shape of the object according to the deformation rule and the parameter. The deformed shape generation unit also moves these selected control points according to the deformation rule and the parameter. In this way, the basic shape is deformed, and the deformed shape is generated as the deformation of the basic shape.

Further, the display shape generation unit generates a free-form surface based on this deformed shape to generate a display shape.

Finally, the display unit displays this display shape to display the deformed object.

(Embodiment) FIG. 1 is an overall configuration diagram showing an object deformation display apparatus as an embodiment of the present invention. As shown in FIG. 1, a basic shape storage unit 1 that stores the basic shape of an object is provided.

Further, a deformation rule storage unit 2 for storing the deformation rule of the basic shape in correspondence with the deformation command is provided.

Furthermore, a designation unit 3 for designating a transformation command is provided. The designation unit 3 can be composed of a keyboard or the like.

A deformed shape generation unit 4 that deforms the basic shape to generate a deformed shape is provided. A display shape generation unit 5 that generates a free-form surface based on the deformed shape generated by the deformed shape generation unit 4 to generate a display shape is provided. Further, a display unit 6 that displays the display shape is provided.

FIGS. 2A and 2B are explanatory diagrams showing the basic shape of the object stored in the basic shape storage unit 1. As shown in FIG. 2 (a), a plurality of control points C for generating a free-form surface.
_The shape represented by _ij is the basic shape of the object. To generate a free-form surface from these control points, each control point
C _ij are arranged in a two-dimensional lattice.

In addition, as shown in FIG. 2B, the basic shape storage unit 1 stores the numbers (i, j) and position coordinates (x _ij , y _ij , z _ij ) of the control points C _ij forming the basic shape. ) And are stored.

FIG. 3 is an explanatory diagram showing the transformation rules stored in the transformation rule storage unit 2. As shown in FIG. 3, in the modification rule storage unit 2, as modification rules corresponding to the command number k indicating each modification command, the control point number (i _k1 , j _k1 ) to be moved by the modification command and its The amount of movement of the control point (dx _k1 , dy _k1 , dz _k1 ) is stored. Such a control point to be moved is called a movement control point.

FIG. 4 is a flowchart showing a deformed shape generation process in the deformed shape generation unit 4. As shown in FIG. 4, first, the command number k indicating the modification command and the parameter p required by the modification command are input and stored from the designation unit 4.
Next, the modification rule corresponding to the command number k is read from the modification rule storage unit 2 and stored. This transformation rule is composed of the movement control point number (i _k1 , j _k1 ) and the movement amount (dx _k1 , dy _k1 , dz _k1 ) of the movement control point.

Next, the number (i, j) and the position coordinates (x _ij , y _ij , z _ij ) of each control point C _ij constituting the basic shape from the basic shape storage unit 1
And are read. Then, this number (i, j) is compared with the number (i _k1 , j _k1 ) of the control point to be moved.

If there is no number (i _k1 , j _k1 ) equal to this number (i, j), there is no need to move this control point C _ij , so the number (i, j) of this control point C _ij And position coordinates (x _ij ,
y _ij and z _ij ) are transferred to the display shape generation unit 5 as the constituent points of the deformed shape.

Also, if this number (i, j) is equal to (i _k1 , j _k1 ),
If there is, the control point C _ij is the movement control point, and therefore the movement processing of the control point C _ij is performed.

FIG. 5 is an explanatory diagram showing a moving process of the control points C _ij in the deformed shape generator 4. As shown in FIG. 5, control points
The position coordinates (x ′ _ij , y ′ _ij , z ′ _ij ) after movement of C _ij are calculated as follows using the movement amount (dx _k1 , dy _k1 , dz _k1 ) of the movement control point and the parameter p. Ask for.

x ′ _ij = x _ij + p · dx _k1 y ′ _ij = y _ij + p · dy _k1 z ′ _ij = z _ij + p · dz _k1 That is, the parameter p indicates the degree of deformation by the deformation command indicated by the number k. . By changing this parameter p, it is possible to perform various degrees of deformation with one deformation command.

Then, the number (i, j) of the control point C _ij and the new position coordinates (x ' _ij , y' _ij , z ' _ij ) are transferred to the display shape generator 5 as the constituent points of the deformed shape.

By performing the above processing for all control points C _ij , the basic shape is deformed to generate a deformed shape, which can be output to the display shape generation unit 5.

In response to the deformed shape generated in this way, the display shape generation unit 5 generates a free-form surface based on the deformed shape and generates polyhedron data as the display shape. An example of the method of generating this free-form surface is as follows: Fujio Yamaguchi, Nikkan Kogyo Shimbun,
"Shape processing engineering by computer display [I]
It is described in [II].

Display unit 6 that has received the polyhedral data as this display shape
Does that display. An example of how to display this polyhedron data is James D. Fole.
y) and Andries Van Dam, Addison-Wesley Publising Company, In
c.), "Fundamentals of Interactive Computer Graphics (Fundamentals of
Interactive Computer Graphics) ".

Through the above processing, the object can be deformed and displayed by the deformation command.

Here, the control point C _ij to be moved and the movement amount (dx _k1 , dy _k1 , dz _k1 ) corresponding to the control point C _ij were used as the transformation rule. Not only such simple movement but also complicated movement including rotation can be used as the transformation rule.

(Effect of the Invention) In the object deformation display method and apparatus of the present invention, any deformation can be set as the deformation rule. Then, the set transformation rule can be easily applied by the transformation command. Therefore, the object can be easily and freely transformed and displayed.

Further, since the free-form surface is used, a smooth shape can be displayed even if the basic shape is composed of a small number of control points. Similarly, even if the basic shape is configured with a small number of control points, the shape can be freely changed.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an object deformation display device as an embodiment of the present invention, and FIGS. 2 (a) and 2 (b) show basic shapes of objects stored in a basic shape storage unit 1. Explanatory drawing, FIG. 3 is an explanatory view showing transformation rules stored in transformation rule storage unit 2, FIG. 4 is a flow chart showing transformation shape generation processing in transformation shape generation unit 4, and FIG. FIG. 7 is an explanatory diagram showing a movement process of a control point C _ij in the shape generation unit 4. In the figure, 1 ... Basic shape storage unit, 2 ... Deformation rule storage unit, 3 ... Designating unit, 4 ... Deformed shape generation unit, 5 ... Display shape generation unit, 6 ... Display unit.

Claims (1)

[Claims] 1. A basic shape storage unit for storing, as a basic shape of an object, a shape represented by a plurality of control points for generating a free-form surface in order to display the shape of the object after being modified by a modification command. And a deformation rule storage unit that stores deformation rules corresponding to a plurality of deformation commands for deforming the basic shape, a deformation command of one of the plurality of deformation commands, and a parameter required by the deformation command. And a modification rule corresponding to the modification command are read from the modification rule storage unit, and a control point to be moved is selected from the plurality of control points according to the modification rule and the parameter. A deformed shape generator that deforms the basic shape to generate a deformed shape by moving it, and generates a free-form surface based on this deformed shape to generate a display shape. A display shape generation unit that, object deformation display device characterized in that it is constituted by a display unit for displaying the display shape.