Patch

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Surface Creation
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New in V9

Surface

Patch

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The Patch command uses surface edges, curves and points as input constraints to create a surface with positional (G0), tangential (G1) or curvature (G2) continuity to the input geometry.

Steps

  1. Select curves, surface edges, or point objects, press Enter when done.

    The input objects are labeled with I, G0, G1, or G2 that indicate the constraint levels.

  2. Click the left or right mouse button on a label to cycle the constraint level forward or backward.

  3. Set options.

Patch Options

Constraints

Click this button to add or remove curves, edges, or points used to define the boundary and interior shapes of the surface.

  • Hover over the green check-mark to reveal a red cross that will clear all constraints.

Set all (G0/G1/G2)

Applies the same constraint level to all boundary edges of the patch surface.

Alternatively, you can hold Shift and left- or right-click a boundary label to do the same.

Stiffness

Controls the roundness and flatness of the surface shape. Higher values produce flatter shapes.

  • Double-click the slider to enter a specific number.

Degree

Sets the UV degrees of the surface from 3 to 5.

Domain

The domain option is used to create a trim domain on the surface that outlines the patch.

Untrimmed

Creates an untrimmed surface. This option is only available when the input segments on the boundary can be merged into four smooth segments.

Projected

Suitable for input objects that are more or less planar; this option is selected automatically if that is the case.

Molded

Default for all other cases. This option creates the best trimming domain for curves that are less planar.

Trim Ends

Attempts to make a closed curve outline of the input curves. If that is possible, it removes dangling curve ends that do not participate in the closed outline. In other words, the selected curves do not need to meet end-to-end if this option is active.

Refine

Uses more UV spans to better fit the surface to the input edges or curves.

Preview

Displays an interactive preview of the surface before it is created. Turn it off to avoid triggering a re-calculation when options are changed.

UV Control

UV Rotation

Rotates the UV directions of the surface up to 90 degrees.

  • Double-click the slider to enter a specific number.

U Spans / V Spans

Sets the initial number of isocurves along the U or V direction.

  • Turning on the Refine setting adjusts the isocurve density to meet the specified tolerances.

Starting Surface

Pick an existing surface that will be pulled to fill the boundary.

  • The output surface will have an identical parameter structure to the starting surface.

  • Using a starting surface allows you to create a surface with a degree higher than 5.

Tolerances

Distance

Controls position matching accuracy.

Angle

Controls tangency matching accuracy.

Internal

Controls the matching accuracy to internal curves or points.

Constraints test results

These labels use different colors to indicate whether the resulting surface meets the requested tolerances of Int (internal), G0 (Position), G1 (Tangency), and G2 (Curvature).

Gray - Not being requested.

Red - The requested continuity fails the tolerance check.

Green - The requested continuity passes the tolerance check

To edit the output surface

  1. Double-click the output surface.

  2. Add or remove curves or edges, press Enter.

  3. Adjust the options.

See also

Create surfaces