Patch Curves

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:

1.

Open the Model layout and use the Curve drawing tool to draw curves that share endpoints (those that are merged).

2.

On the left panel, open the Duplicate sub-tab and click Patch Curves.

3.

In the viewport, click to activate the tool.

4.

Click the curve edge points. 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.

Patch Curve Options

The following options are available for adjusting the Patch Curves tool.

Mode	Interactively select edges to define the patch surface. • Define Patch - Define the patch position and other tool options. • 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.