[Terry Capps]

You got the first part, that generates some vertex point data and angles, working. A second part allows the insertion of a new vertex. The particular one that I use is the insertion of a new vertex an equal distance between the two selected. This new vertex is not along an edge which could be done with ac3d's "Insert Vertex" function. I have included some images illustrating the error. The first image illustrates the display of basic vertex data and angles. The second image indicates the selection of a vertex to be inserted in the middle on the TVI - Guideline UI. The third image shows the error generated.

Thank you