Patching is a means of generating a smooth surface from 3 or 4 curves that define the contour edges of the surfaces. Multiple patches can be combined to create a closed volume (like a contoured bottle). The Patch Curves tool can be found under the Duplicate tab of the toolbox, or within the Curves palette. To make a Spline Patch, do the following:
| 1. | Use the Curve drawing tool to draw curves that share endpoints (those that are merged). |
| 2. | On the default interface, under the Model or Model Quad layouts, you can find the modeling tools toolbar. Click the Duplicate sub-tab. |
| 3. | Select the Patch Curves tool; it can be found between the Bridge and Curve Extrude buttons. |
| 4. | In the viewport, click the curve edges. By clicking on a sequence of edges, you can define a patch. |
| 5. | Edges can also be clicked and dragged, extending patch edges, if necessary. |
You can interactively adjust the control points on the curve while the patches are re-made to follow the new contours. You can pick edges and set the number of segments for that edge as the patching updates to match. Patching generates UVs that follow the grid of quads generated for each patch.
The following Patch options are available for adjusting the Patch Curves tool:
• Mode - interactively select edges to define the patch surface:
• Extend- drag edge handles to extend patch edges.
• Move Knot- interactively adjust specific knots in the patch.
• Move Edge- move the selected edge.
• Edit Edge- select edges and modify the number of knots.
• Knots - defines the number of divisions along the length of a curve for editing.
• Start/End Control Vertex - the flag for side curves to extend, allowing control over curvature for end segments.
• Perpendicular - the number of divisions along a perpendicular side.
• Parallel - the number of divisions along a parallel side.
• Save Boundaries - retains the boundary curves.
• Freeze - when the tool is dropped, the patch surface becomes editable polygons.
• Flip - reverses the normal direction of the patched surface.
• Make UVs - generates an automatic UV map for the patched surface for texturing.