Hi GrumpyOldMan,
You may have a look at the command VertexCoords, which is there exactly for that purpose.
http://www.blitzbasic.com/b3ddocs/command.php?name=VertexCoords&ref=3d_cat
The way you have to move the vertex to perform a geometric rotation, involves a bit of math though; try out first with simple meshes, then apply the concept to the whole mesh.
Hope this helps,
Sergio.
Are there any readily available functions or formulas to rotate part of a mesh around it's 'local' origin?
As far as I know, there's no such a command. What you could do, is to move the vertex which belongs to the part of the mesh you want to rotate, in order to perform the needed rotation.You may have a look at the command VertexCoords, which is there exactly for that purpose.
http://www.blitzbasic.com/b3ddocs/command.php?name=VertexCoords&ref=3d_cat
The way you have to move the vertex to perform a geometric rotation, involves a bit of math though; try out first with simple meshes, then apply the concept to the whole mesh.
Hope this helps,
Sergio.