Tangent and curvature have to d o with curve continuity. 3 types of continuity: g0 for point, g1 for tangent, g2 for curvature. Google class a surfacing and you'll get a good idea of what is involved.
I am creating an animation in matlab using vrml. The problem is, I found out that my vrml nodes are all "group" type, not "transform" type. Only transform type nodes can be moved around. Do any of you know how to change the nodes? I went through the respective demos, but none covered how to...