JP2800435B2 - Method and apparatus for rotating figures in three-dimensional computer graphics - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for rotating figures in computer graphics used in a three-dimensional CAD apparatus or the like.

[0002]

2. Description of the Related Art Conventionally, in displaying graphics of a building or the like by three-dimensional computer graphics on output means such as a display, the height direction of the building or the like often coincides with the Y-axis direction. . It is also known that coordinate data of a graphic is converted by matrix operation around X, Y, and Z axes in order to rotate and display the graphic to be displayed. In this case, conventionally, the internal processing of the operation is X, Y, Z
The axes were executed in order.

[0003]

However, in the matrix operation in the above-described order, when a complicated rotation operation is performed, the graphic such as an architectural drawing displayed on the output means is inclined in the height direction. In some cases, inconveniences may occur, making operation difficult. SUMMARY OF THE INVENTION The present invention solves the above-described problem. By changing the order of matrix operations, a three-dimensional computer that is easy to operate does not tilt in the height direction of a figure even when a complicated rotation operation is performed. An object of the present invention is to provide a method and an apparatus for rotating a graphic in graphics.

[0004]

According to a first aspect of the present invention, there is provided a three-dimensional coordinate system in which coordinate information of a graphic is represented by a three-dimensional spatial coordinate system, and the coordinate of the graphic is rotationally transformed by a matrix operation. In the method of rotating graphics in computer graphics, when a rotation conversion instruction about X, Y, and Z axes is input, rotation conversion by matrix operation is performed in the order of Y, X, and Z axes. . According to a second aspect of the present invention, there is provided storage means for storing graphic data representing coordinate information of a graphic in a three-dimensional space coordinate system;
Input means for inputting information for rotating the graphic around the X, Y, and Z axes; calculating means for performing coordinate conversion of the graphic by matrix calculation based on the information input by the input means; In the apparatus for rotating figures in three-dimensional computer graphics provided with output means for displaying the figure data processed in step (a), the arithmetic means executes coordinate transformation of the figures by matrix operation in the order of Y, X and Z axes. It was made.

[0005]

According to the method or the apparatus of the present invention, when an instruction for rotationally transforming the X, Y, and Z axes is input, the coordinate information of the figure represented in the three-dimensional space coordinate system is represented by Y, X , And Z-axis coordinate conversion by matrix operation. As a result, if the figure is an object, the Y-axis rotation is necessarily rotated about an axis in the height direction of the object.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a three-dimensional CAD system which is an embodiment of a method or apparatus according to the present invention. In the figure, a CAD system includes a hard disk 1 storing architectural drawing files and the like, a keyboard 2 (input means) for inputting a coordinate position and the like on the architectural drawing, and a valuator 3 (input means) such as a dial joystick; A CAD body 4 for taking in the input coordinate data and displacement and calculating and editing graphic data of the architectural drawing;
A display 5 (output means) for displaying graphic data processed by the main body 4 and a plotter 6 (output means) for outputting the graphic data as architectural drawings on recording paper. The CAD body 4 includes a CPU 7 for controlling an input device and the entire device, and a ROM 8 for storing a CAD program.
And a RAM 9 serving as a work area for editing architectural drawing data
And an interface 10 for transferring data and the like between the CAD body 4 and the input / output device.

FIG. 2 shows a mechanism of a rotation operation in a space by three-dimensional computer graphics.
(B) and (c) show the rotation mode when rotated about each of the X, Y, and Z axes. The input of the rotation amount is performed by the valuator 3. In the present embodiment,, and of the dial correspond to the amounts of rotation about the X, Y, and Z axes, respectively.

FIG. 3 is a flowchart showing a processing operation performed by the CAD main unit 4 when a rotation operation of a figure is instructed. First, the valuators, are initialized (the valuator value is set to 0) (step 1, hereinafter referred to as S1), and the valuators, are enabled (S1).
2) Check whether there is a valuator input (S)
3). When there is an input, the amount of rotation about the X, Y, and Z axes is set based on the amount of displacement of the dial, and (S4). Subsequently, a conversion matrix is obtained by the following equation (S5). M '= [Yrot] [M] [Xrot]
[Zrot] Next, using the obtained conversion matrix M ', the following matrix conversion is performed, and a graphic based on the converted graphic data is displayed on the display 5 (S6).

Here, an X-axis rotation matrix [Xro
t], the Y-axis rotation matrix [Yrot], and the Z-axis rotation matrix [Zrot] are respectively [Xrot] = 1000 cos θ sin θ 00-sin θ cos θ 00 00 01 [Yrot] = cos θ 0-sin θ 0 1 0 0 0 sin θ 0 cos θ 0 0 0 0 1 [Zrot] = cos θ sin θ 0 0 -sin θ cos θ 0 0 0 0 0 0 0 0 0 0 1 In the above description, [] in the determinant on the right side is omitted.

The coordinate transformation including the translation is expressed by the following equation. [X ', y', z ', 1] = [X, Y, Z, 1] [M'] However, when the axis of rotation is not the origin, the following equation is obtained. [X ', y', z ', 1] = [X, Y, Z, 1] [-T] [M'] [T] where [T] = 1 0 0 0 0 0 0 0 0 0 0 It is assumed that 00 Px Py Pz 1. Note that Px, Py, and Pz are axes of rotation.

Now, the method of the present invention will be described in comparison with a conventional method. FIG. 5 shows a coordinate transformation by a conventional rotation method, and a matrix operation expression of the coordinate transformation is represented by M '= [M] [Xrot] [Yrot] [Zrot]. As shown in the figure, in the related art, since the rotation process is performed in the order of X rotation and Y rotation, the axis of the object displayed on the screen in the height direction is inclined. FIG. 4 shows the coordinate transformation by the rotation method according to the present invention, and the matrix operation formula of the coordinate transformation is represented by M '= [Yrot] [M] [Xrot] [Zrot]. As shown in the figure, in the method of the present invention, even if the operation is performed in the order of X rotation and Y rotation, the Y rotation is performed first as internal processing, so the Y axis rotation is always the Y axis unique to the object. (The axis in the height direction), and the X-axis rotation always rotates about the horizontal axis of the object.

[0012]

As described above, according to the present invention, when a figure is rotated around each of the X, Y, and Z axes, the matrix operation for coordinate conversion is performed in the order of Y, X, and Z, thereby providing Y. The axis rotation always rotates about the axis in the height direction of the figure (object).
The X-axis rotation always rotates about the horizontal axis of the figure (object), so that even if complicated rotation is performed, the axis in the height direction does not tilt, and the operation is easy.

[Brief description of the drawings]

FIG. 1 is a block diagram of a three-dimensional CAD system in which the present invention is implemented.

FIGS. 2A, 2B, and 2C are conceptual diagrams when a figure is rotated around X, Y, and Z axes.

FIG. 3 is a flowchart showing a processing operation according to the present invention.

FIG. 4 is a diagram showing coordinate transformation by a rotation method according to the present invention.

FIG. 5 is a diagram showing coordinate conversion by a conventional rotation method.

[Explanation of symbols]

 3 Valuator 4 CAD body 5 Display

Claims (2)

(57) [Claims] 1. A method of rotating a figure in three-dimensional computer graphics in which coordinate information of the figure is expressed in a three-dimensional space coordinate system and the coordinates of the figure are rotationally converted by a matrix operation, the method comprising: When a conversion instruction is input, rotation conversion by matrix operation is performed by Y, X,
A method of rotating a figure in three-dimensional computer graphics, the method being performed in the order of the Z axis. 2. A storage means for storing graphic data expressing coordinate information of a graphic in a three-dimensional space coordinate system, and storing the graphic in X,
Input means for inputting information for rotating about the Y and Z axes, calculating means for performing coordinate conversion of a figure by matrix calculation based on the information input by the input means, and processing by the calculating means In the apparatus for rotating figures in three-dimensional computer graphics provided with output means for displaying figure data, the calculating means executes coordinate transformation of the figures by matrix operation in the order of Y, X and Z axes. A device for rotating figures in three-dimensional computer graphics.