JP2822384B2 - Graphic data editing method and graphic data editing apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in the following order.

A Industrial field B Outline of the invention C Prior art D Problems to be solved by the invention E Means for solving the problems (FIGS. 2, 9 and 15)
Figure, Figure 20).

F action (FIGS. 2, 9, 15, and 20) G Example (G1) Patch configuration (FIG. 1) (G2) Curved surface deformation design operation (G2-1) Straight line writing process (Fig. 2, Fig. 3 to Fig. 8) (G2-2) Process of exchanging boundary curves (Fig. 9, Fig. 10 to Fig. 14) (G2-3) Change length of control edge vector Processing (FIGS. 15, 16 to 19) (G2-4) Processing for Changing the Position of Internal Control Point (FIGS. 20, 21 to 24) (G3) Other Embodiments H Invention BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a graphic data editing method and a graphic data editing apparatus, and in particular, CAD (computer aided design), CAM (com
It is suitable for application when designing the shape of an object by puter aided manufacturing).

B. Summary of the Invention The present invention simultaneously displays graphic data selected and designated by a designer and a plurality of characteristic information indicators representing the geometrical characteristics of the graphic data, and allows design from among the plurality of characteristic information indicators. By performing the editing process of the graphic data based on the feature information indicator specified by
The deformed design can be easily performed without imposing an excessive burden on the designer.

C Conventional Technology For example, when designing a shape of an object having a free-form surface (which cannot be defined by a quadratic function) using a CAD method (geometric modeling), generally, the design is performed in a three-dimensional space through which the curved surface must pass. Are designated by a plurality of points (referred to as "nodes"), and a boundary curve network connecting the plurality of designated nodes is calculated by a computer using a predetermined vector function. Create a curved surface. Thus, a large number of framework spaces surrounded by boundary curves can be formed (such a process is called a framework process).

The boundary curve network formed by such framework processing is
The design itself represents the rough shape to be designed, and if the surface that can be represented by a predetermined vector function can be interpolated using the boundary curves surrounding each framework space, the designer as a whole designed Free-form surfaces can be generated. Here, the curved surface formed in each frame space forms a basic element constituting the entire curved surface, and this is called a patch.

Conventionally, patches with curved surfaces that have special features in terms of shape can be stretched so that they are as smooth as possible between each other, and as a method that can prevent the computer processing time from being lengthened. Bezier formula, spline formula, Coons (Co
ons), Furgason, etc.
A method has been proposed in which a patch consisting of a free-form surface is generated under the condition of a tangent plane continuation using a parametric vector function represented by the following tensor product (Japanese Patent Application No. 60-27).
No. 7448, Japanese Patent Application No. 60-290849, Japanese Patent Application No. 60-298638, Japanese Patent Application No. 61-15396, Japanese Patent Application No. 61-33412, Japanese Patent Application No. 61-5979
No. 0, Japanese Patent Application No. 61-64560, Japanese Patent Application No. 61-96368, Japanese Patent Application No. 6
No. 1-69385).

D Problems to be solved by the invention In general, when designing the shape of an object by CAD, the designer must use the shape once designed.
It is common to repeat a deformation operation of a part of a curved surface or a curve until the shape becomes sufficiently satisfactory from the design intention (this is called a deformation design operation). It is necessary to repeat an operation of specifying one end point on a curved surface or a curve to be used as a reference point and specifying a limit point representing a range to be changed from the reference point to input a deformation range to a computer. is there.

In practice, the designer executes such a deformed design operation while changing the position and range on the curved surface as necessary, so that it is unavoidable that the number of end point designation input operations on the computer becomes enormous.

However, in conventional CAD, generally, when designating a reference point on a curved surface and a limit point indicating a change range, a graphic element (for example, an arc, a straight line, etc.) representing the curved surface on which the reference point and the limit point are placed is specified. A method is used in which a designer once executes an operation of designating a reference point and a limit point while being displayed on a display screen.

However, when such graphic elements are displayed on the display screen, a series of conversion operations is required, which may put an excessive operational burden on the designer.

If the curved surface on which the reference point and the limit point are placed is a circular arc, a conversion process for displaying the center point of the circular arc is executed to convert the curved surface between the reference point and the limit point. It is necessary to prepare for. This means that the designer cannot directly specify the shape deformation, resulting in an intervening transformation operation.

The present invention has been made in view of the following points, and proposes a graphic data editing method and a graphic data editing apparatus that can further reduce the operational burden of a designer when performing a deformed design operation on a curved surface. Things.

E. Means for Solving the Problem In order to solve the problem, the present invention uses a computer to roughly describe an object surrounded by a boundary curve by frame processing and specified by a plurality of nodes. A large number of framework spaces representing shapes are formed, and in the framework space, vector functions are obtained by sequentially designating positions in the respective framework spaces at predetermined intervals by using parameters that are sequentially designated, and smoothing each framework space with each other. The control edge vector representing the shape of the curved surface in each framework space is obtained to connect to the frame surface space, and the vector function and the control edge vector are used as a plurality of control points to represent the detailed surface shape of the object. Generates a plurality of graphic data, performs control to display them on the display device, and inputs a selection command for selecting desired graphic data from the plurality of graphic data. In order to edit the curved surface of the plurality of graphic data displayed on the display device into a desired shape, exchange of the boundary curve, change in the length of the control side vector or change in the position of the control point is input as an edit processing command. The apparatus extracts the characteristic information necessary for the editing processing instruction from the plurality of characteristic information based on the plurality of control points and the nodes related to the graphic data selected by the selection instruction and inputting the extracted characteristic information. A plurality of graphic data are simultaneously displayed on the display device as a feature information indicator, and feature information corresponding to the feature information indicator selected and instructed by the input device from the displayed feature information indicator is selected feature information, Based on the selected feature information, the editing process of the graphic data based on the editing process command is executed.

F function When selecting and redesigning desired graphic data from a plurality of graphic data formed by a curved surface shape, the boundary curve is replaced, the length of the control side vector is changed, or the position of the control point is changed. By inputting it as an edit processing command and specifying and displaying only necessary feature information indicators as restriction conditions when redesigning the selected graphic data together with the selected graphic data, the selected graphic data and the edit processing command are displayed. The redesign process can be easily executed while visually confirming only the characteristic information indicator corresponding to.

G Example Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

(G1) Configuration of Patch In this embodiment, a boundary curve representing the boundary of the framework-processed quadrilateral framework space, and a patch attached to each quadrilateral framework space Is Is expressed using a vector function represented by a cubic Bezier equation. In equation (1), Is a curved surface stretched between two adjacent frame spaces, that is, a first quadrilateral patch as shown in FIG. And a second quadrilateral patch Is a position vector representing the position of one end of the boundary (hereinafter referred to as a shared boundary) held by both, and a position vector representing the position of the other end. And the first patch Position vector When, Together with a node specified at the time of framework processing.

Thus, the first and second patches Are nodes It can be seen that they are surrounded by the four boundary curves.

Nodes of these boundary curves The boundary curve between them constitutes the common boundary COM and the two control points Defines a third-order Bezier equation.

In contrast, the first patch Nodes Boundary curve between, Boundary curve between, The boundary curves between each two control points Stipulated by

Boundary curve between, Boundary curve between, The boundary curves between each two control points Stipulated by

In addition to this, the first and second patches The internal shape of the internal control point Stipulated by

In equation (1), E and F are shift operators in the u and v directions, and are patches. Control point represented by the above position vector For the following equation: With the relationship

Here, u and v are parameters in the u and v directions, and are defined in the range of 0 to 1 as 0 ≦ u ≦ 1 (4) 0 ≦ v ≦ 1 (5) .

Thus, as shown in FIG. 1, the first and second patches For each node Using the coordinates (u, v) that take the u axis in the horizontal direction and the v axis in the vertical direction from Can represent coordinates on a free-form surface. Thus, the following equation obtained by expanding equation (1) A vector function that can be expressed by a mathematical expression of the product sum of 16 control points including 4 nodes and 12 control points (which are collectively called control points) and parameters u and v as shown in Patch Obtain all the above vector positions and hence their shapes.

Where the patch The connection shape between them is a control edge vector that represents the positional relationship between control points Can be controlled by

(G2) Deformation design operation of curved surface When it is desired to deform the shape of a free-form surface represented by a patch stretched by the method shown in FIG. 1, a feature represented by a control point of each patch is used. A deformation operation is performed using the control point as a reference point and a limit point.

(G2-1) Processing for writing a straight line When writing a straight line on a patch on the display screen, the designer and the design device execute a curved surface deformation process in accordance with the straight line writing operation processing means RT1 in FIG.

First, in step SP1, the designer selects a menu to draw a straight line. At this time, the design apparatus displays a curved surface to be processed on the display screen as shown in FIG. At this time, in step SP2, the design apparatus displays a cursor (in this embodiment, formed of cross-shaped straight lines KX and KY) on the display screen as shown in FIG.

In the case of this embodiment, five quadrangular patches are to be processed. Is displayed, each patch In FIG. 7, a curve of u = 0.5 and v = 0.5 is indicated by a broken line, thereby expressing the surface shape of each patch.

In the next step SP3, the designer, as shown in FIG. By operating the pick according to the Enter the selection information.

At this time, the design apparatus moves to step SP4, and as shown in FIG. Is displayed.

Where the four nodes Patch By representing the rough shape (given when framed) of the patch Shape characteristic, and thus a patch on the display screen. Means that the geometrical characteristics of can be extracted and displayed.

Subsequently, in the next step SP5, as shown in FIG. 6, the designer sets one end point, that is, a control point to be set with the cursors KX and KY as reference points. By picking this point in accordance with, selection information is input to the design device.

At this time, the design device moves to step SP6 and selects the selected end point. Is displayed in a color different from the color of the other curves and control points on the display screen (for example, black displayed on a white background screen), for example, red, whereby the control point is displayed. Is displayed, and cursors KX and KY are displayed.
Turn off. Thus, the designation of the reference point is completed.

Subsequently, the design apparatus informs the designer that the process has started to specify the limit point by displaying a cursor in step SP7. At this time, the designer and the design device operate in the same manner as described above for steps SP3 to SP5.
Patch to process cursors KX and KY in step SP8 The picking operation is performed in accordance with the control, and at this time, the design device again controls the four control points in the next step SP9. Is displayed, and at step SP10, as shown in FIG. 7, one of the four control points, for example, the control point Move the cursor to and perform a pick operation.

At this time, the control point selected as the limit point is In response to this, the design apparatus moves to step SP11 in response to this, and as shown in FIG. 8, the control point designated as the reference point Control points specified as limit points from First, the calculation for creating the straight line L1 on the display screen is executed and displayed on the display screen.

Thus, the design device ends the operation processing in step SP12.

According to the display method shown in FIG. Shape characteristics of the patch By writing the straight line L1 using the control point above, the patch to be processed is Patching can be directly performed without the need for intermediate processing such as separately preparing a curve for representing the shape of the image and displaying it on the display screen. It is possible to easily execute a modified design process such as writing a straight line on the top.

(G2-2) Processing for exchanging boundary curves Once a patch is put on the framework space formed by the framework processing, a curved surface having a desired shape cannot be generated because the framework processing is inappropriate. in case of,
The designer and the design device can replace the inappropriate boundary curve with the boundary curve designated by the designer by executing the boundary curve replacement operation process RT2 shown in FIG.

First, at step SP21, the designer selects a menu for executing a process of exchanging boundaries. At this time, the design apparatus proceeds to step SP22, and as shown in FIG. 10, a patch for forming a curved surface to be processed. Is displayed, and the cursors KX and KY are displayed to wait for the input operation of the designer.

In this state the designer goes to step SP23
As shown in FIG. 11, the patches KX and KY Pick operation according to. At this time, the design device moves to step SP24, and Four boundary curves COM11, COM12, COM13, COM14 (11th
By changing the color of (Fig.) To red, the patch Indicates that was picked and the cursor disappears. Thus, the patch selection process ends.

Next, the design device moves the cursor at step SP25.
Display KX and KY again and wait for designer input operation. In this state, at step SP26, the designer moves the cursor to a boundary curve to be replaced, for example, COM14, of the four boundary curves COM11 to COM14 and performs a pick operation, as shown in FIG. At this time, the design apparatus moves to step SP27 and erases the cursor to indicate that the boundary curve selection processing has been completed.

Next, the design device moves to step SP28 and moves the cursor.
Display KX and KY again and wait for designer input operation. Therefore, at step SP29, the designer moves the cursor KX to the curve L2 to be replaced as the boundary curve, as shown in FIG.
Pick up with KY.

At this time, the design apparatus proceeds to step SP30 and recalculates a new curved surface incorporating the curve L2 as a new boundary curve COM14X, as shown in FIG.
Patch with two boundary curves COM11X, COM12X, COM13X, COM14X Is displayed on the display screen.

Thus, the design device ends the operation processing in step SP31.

According to the processing method shown in FIG. 9, when the shape of the curved surface of the patch already generated is deformed, By displaying the four boundary curves COM11 to COM14 representing the geometric characteristics of the shape prior to the deformation design operation and letting the designer select one of them, a new figure is newly added when the designer performs the deformation design. It is possible to eliminate the necessity of performing a process of writing an element, and it is possible to execute a deformed design operation of a curved surface with a simple operation corresponding to the necessity.

(G2-3) Processing to change the length of control edge vector The connection between patches is controlled by the control edge vector. (FIG. 1) and thus the control edge vector Represents the characteristic of the shape of the curved surface around it. If the length of the control edge vector is changed, the shape of the curved surface around it can be changed.

When the length of the control edge vector is changed in this way, the designer and the design device execute the control edge vector length change operation process RT3 in FIG.

First, in step SP41, when the designer selects a menu for changing the length of the control edge vector, the design device moves the cursor in step SP42 as shown in FIG.
Display KX, KY and wait for designer input operation.

In this state, the designer changes the cursors KX and KY in step SP43 to the patch to be changed. Pick operation according to.

At this time, the design device proceeds to step SP44 with 16 control points as shown in FIG. Is displayed on the display screen, and in step SP45, the control edge vector of each boundary curve (in this embodiment, the node Control edge vector about Is changed to red and displayed. Thus, a state is obtained in which all the control side vectors that can be selected by the designer on the display screen are displayed in an easily viewable display mode.

In this state, the designer proceeds to the next step SP46, as shown in FIG. Move the cursor KX and KY to and perform the pick operation.
The selected control edge vector in step SP47 Is input using a separate input operation means. In response to this, the design device moves to step SP48, where the changed control edge vector is changed. Patch using After recalculating the curved surface shape of the new patch, as shown in FIG. Is displayed, and a new control point is set in the next step SP49. Is displayed on the display screen, and the operation process ends in step SP50.

According to the processing method of FIG. 15, the patch that the designer wants to change Control edge vector representing the shape characteristics of Is displayed on the display screen prior to the deformation design operation, so that the change of a considerably complicated curved surface can be performed simply by selecting one of the control side vectors and inputting the change magnification data. Can be easily implemented.

(G2-4) Processing to change the position of internal control points Four internal control points (Fig. 1) is a quadrilateral patch Has the characteristic of controlling the internal shape of the patch. Therefore, these internal control points represent the characteristics of the curved surface shape of the patch.
By changing the position, the curved shape of the patch can be changed.

When the user wants to change the internal control point, the designer and the design device execute the internal control point position change operation process RT4 shown in FIG.

First, in step SP61, when the designer selects the menu for changing the internal control point, the design device
Moving to SP62, as shown in FIG. 21, the curved surface to be designed is expressed on the display screen, and the cursors KX and KY are displayed to wait for the input operation of the designer.

In this state the designer goes to step SP63
As shown in Fig. 22, the patches KX and KY Pick operation according to.

At this time, the design device moves to step SP64 and 16 control points Is displayed, then go to step SP65 4 internal control points corresponding to The internal vector to is displayed in red.

Thus, the design device has internal control points as deformation operation elements that can be selected by the designer. Is displayed more conspicuously than the surrounding display elements, so that the designer waits for the input operation in a state where the designer can easily select.

In this state the designer goes to step SP66
As shown in FIG. 23, one of the four internal control points is determined by the cursors KX and KY, for example. Is picked up, and at step SP67, the internal control point The position data for changing the position is input by a separate input means.

At this time, the design apparatus moves to step SP68, and as shown in FIG. 24, the inputted new internal control point. A new curved surface shape is calculated on the basis of the data and displayed on the display screen, and a new internal control point is set in step SP69. Is displayed, the operation process is terminated in step SP70.

According to the processing method of FIG. 20, prior to the designer's deformation design operation, the internal control points representing the geometric characteristics of the patch are displayed prominently on the display screen,
The designer can easily deform the curved surface of the patch simply by selecting one of the control points and inputting data of a new change position.

(G3) Other Embodiments (1) In the above-described embodiment, a case was described in which a patch represented by a cubic Bezier equation was set up in the framework space. May be.

(2) In the above-described embodiment, a case has been described in which a patch represented by a Bezier formula is stretched in the framework space. However, the present invention is not limited to this, and other types such as a spline formula, a Coons formula, and a Forgersson formula are used. A vector function may be used. In other words, the present invention can be widely applied to a case where a free-form surface is expressed using a parametric vector function represented by a tensor product.

(3) In the above-described embodiment, the present invention is applied to the case where a free-form surface is generated using a quadrilateral patch. However, the present invention is not limited to this. It can be widely applied to a case where patches and quadrilateral patches are mixed.

H Advantageous Effects of the Invention As described above, according to the present invention, when selecting and redesigning desired graphic data from a plurality of graphic data formed by a curved surface shape, the boundary curve is replaced and the control edge is changed. A change in the length of a vector or a change in the position of a control point is input as an edit processing instruction, and specified and displayed together with the selected graphic data as limiting conditions for redesigning only the necessary feature information indicators according to the edit processing instruction By doing so, it is possible to easily execute the redesign process while visually checking only the selected graphic data and the feature information indicator corresponding to the edit processing command, and thus visually redesign the graphic data by the designer. In addition to ease of operation, the operational burden can be further reduced.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing the configuration of a free-form surface to which the design surface display method according to the present invention is applied, FIG. 2 is a flow chart showing a straight line writing operation process, and FIGS. FIG. 9 is a schematic diagram showing a display on a display screen sequentially processed according to the processing procedure, FIG. 9 is a flowchart showing a boundary curve exchange operation processing, and FIGS. 10 to 14 are processing procedures shown in FIG. FIG. 15 is a schematic diagram showing a display on the display screen processed according to the above, FIG. 15 is a flowchart showing a control side vector length changing operation process, and FIGS. 20 is a schematic diagram showing the display on the display screen to be processed, FIG. 20 is a flowchart showing the internal control point position change operation processing, and FIGS. 21 to 24 are processed according to the processing procedure of FIG. FIG. 7 is a schematic diagram illustrating a display on a display screen to be displayed.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G06T 17/00 JICST file (JOIS)

Claims (12)

(57) [Claims] 1. Using a computer, form a plurality of framework spaces which are surrounded by a boundary curve by a framework process and which represent a rough shape of an object specified by a plurality of nodes,
In the above-mentioned framework space, a position in each of the framework spaces is sequentially designated by a parameter sequentially designated at a predetermined interval to obtain a vector function. A control edge vector representing the shape of the curved surface is obtained, and the vector function and the control edge vector are used as a plurality of control points to represent a detailed surface shape of the object, thereby generating a plurality of graphic data formed by the curved surface shape, A graphic data display control step of controlling the display of the graphic data on a display device, a graphic selection step of inputting a selection command for selecting desired graphic data from the plurality of graphic data, and the graphic data displayed on the display device In order to edit the curved surface into a desired shape, the boundary curve is replaced, the length of the control edge vector is changed, or the An edit processing command input step for inputting a change in the position of a point as an edit processing command by an input device; and a plurality of feature information based on the plurality of control points and the nodes regarding the graphic data selected by the selection command. A feature information display control step of extracting feature information necessary for the edit processing command from the above, and controlling to display the extracted feature information as a feature information indicator on the display device simultaneously with the plurality of graphic data; A feature information selection step in which feature information corresponding to the feature information display element selected and instructed by the input device from the feature information display elements displayed in the feature information display control step is selected feature information; and And an edit processing step of executing the edit processing of the graphic data based on the edit processing command based on the information. Graphic data editing method to. 2. The graphic data editing method according to claim 1, wherein said characteristic information indicator is an indicator representing said control point and / or node. 3. The graphic data editing method according to claim 1, wherein the feature information indicator is a vector information indicator representing a vector based on the control point and / or the node. . 4. The vector information indicator comprises, based on a predetermined control point and / or a node among the control points and / or nodes, a vector directed to a control point and / or a node adjacent to the predetermined control point and / or the node. 4. The graphic data editing method according to claim 3, wherein the graphic data is a display element representing the following. 5. The graphic data editing method according to claim 1, wherein said vector function is a function defining a free-form surface. 6. The graphic data editing method according to claim 5, wherein the feature information indicator is a shared boundary held by the two free-form surfaces. 7. Using a computer, form a plurality of framework spaces which are surrounded by a boundary curve by framework processing and represent a rough shape of an object specified by a plurality of nodes.
In the above-mentioned framework space, a position in each of the framework spaces is sequentially designated by a parameter sequentially designated at a predetermined interval to obtain a vector function. A control edge vector representing the shape of the curved surface is obtained, and the vector function and the control edge vector are used as a plurality of control points to represent a detailed surface shape of the object, thereby generating a plurality of graphic data formed by the curved surface shape, Graphic data display control means for controlling the display of the graphic data on a display device; graphic selection means for inputting a selection command for selecting desired graphic data from the plurality of graphic data; and the graphic data displayed on the display device In order to edit the curved surface into a desired shape, the boundary curve is replaced, the length of the control side vector is changed, or the control point is Edit processing command input means for inputting the change in position as an edit processing command by an input device; and the editing based on a plurality of feature information based on a plurality of control points and a plurality of nodes regarding graphic data selected by the selection command. Feature information display control means for extracting feature information necessary for a processing instruction and performing control to display the extracted feature information as a feature information indicator on the display device simultaneously with the plurality of graphic data; A feature information selecting means for selecting feature information corresponding to a feature information indicator selected and instructed by the input device from the displayed feature information indicator as selected feature information; and a feature information selecting means based on the selected feature information. Editing processing means for executing the editing processing of the graphic data based on the editing processing command. 8. The graphic data editing apparatus according to claim 7, wherein said characteristic information indicator is an indicator representing said control point and / or node. 9. The graphic data editing apparatus according to claim 7, wherein said characteristic information indicator is a vector information indicator representing a vector based on said control point and / or node. . 10. The vector information indicator is, based on a predetermined control point and / or a node among the control points and / or nodes, a vector directed to a control point and / or a node adjacent to the predetermined control point and / or the node. 10. The graphic data editing apparatus according to claim 9, wherein the display element is a display element representing 11. The graphic data editing apparatus according to claim 7, wherein said vector function is a function defining a free-form surface. 12. The graphic data editing apparatus according to claim 11, wherein the characteristic information indicator is a shared boundary held by the two free-form surfaces.