Triangulation algorithm

You use this function to change the triangulate stitch algorithm while Surpac is running. The stitch algorithm is the algorithm used by the Create 3DM functions to create triangles to stitch segments together. You will find that different stitch algorithms will give you better results in different geometric situations.

To run this function: Choose Solids > Triangulate > Triangulation algorithm, or...

In the Function Chooser, type STITCH ALGORITHM TOGGLE, and press ENTER.

You have four options, which are represented by the integers 0-3 on the TOGGLE STITCH ALGORITHM form.

The options are:

0: old algorithm
1: new algorithm
2: old algorithm with transforms
3: new algorithm with transforms.

The default value of the option in the defaults.mst file is 3.

Note: The old algorithm is the algorithm which existed in Surpac prior to Version 3.0.

The new algorithm was introduced in Version 3.0 and works faster than the old algorithm in most situations. Two additional options were added in Version 3.1 to help prevent the creation of twisted or self-intersecting trisolations. These new options use the old and new algorithms but have an additional step which transforms the segments so they are parallel and have aligned centroids before performing the stitching and then removing the transform .

When you change the option using TOGGLE STITCH ALGORITHM the option will remain at the new value until you change it again or exit Surpac. To change the default value of the option, edit the triangulate stitch algorithm value in your defaults.ssi file.

The transforms options can be applied when you are stitching together the whole of two closed segments, at least one of which must consist of coplanar points. If you have requested a transforms algorithm but these conditions are not satisfied then the stitch algorithm will default to the old or new algorithm without the transforms.

The following Create 3DM functions are sensitive to the choice of the triangulate stitch algorithm:

Enter stitch algorithm

Enter the stitch algorithm to use for solids creation.

Complete the TOGGLE STITCH ALGORITHM form and choose Apply to change the algorithm.