# Polystitch SOP

## Summary[edit]

The Polystitch SOP attempts to stitch polygonal surfaces together, thereby eliminating cracks that result from evaluating the surfaces at differing levels of detail.

First, the boundaries of all the polygons to be stitched are found. An edge is a boundary edge if it is shared by no other polygon. The uniqueness of edges is determined by point numbers, and not by spatial positioning. Each boundary is then split at each "corner" into a number of pieces. A list of corner points can be manually specified, or any point at which the boundary changes direction by a certain amount can be flagged as a corner.

Finally, any two boundary pieces that are within the tolerance of each other are stitched together. This is performed by snapping the points of the high detail edge to those of the low detail edge.

## Parameters - Page

Polygons to Stitch `stitch`

- The polygons to consider for stitching.

Corner Points `corners`

- A list of point numbers that are to be considered breaks in the boundary edges.

Max Dist to Stitch `tol3d`

- The maximum distance two edges can be from each other and still be stitched.

Consolidate Points `consolidate`

- When several points along one edge are snapped to the same position, consolidate them into a single point. This only consolidates along the boundary, not across the boundary.

Automatically Find Corners `findcorner`

- Whenever an edge changes direction at a point more than the specified angle, it will mark that point as a corner.

Corner Angle `angle`

- The maximum angle a boundary point can change before it is considered a corner.

## Operator Inputs

- Input 0 -

TouchDesigner Build:

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An Operator Family that reads, creates and modifies 3D polygons, curves, NURBS surfaces, spheres, meatballs and other 3D surface data.