@Craigson I’ll try to help flush out Paul’s suggestions.
I’d start by looking at VboMeshApp to get an idea how to have position data in a dynamic buffer and indices in a static one. You’ll want to start with just those two to keep things simple and come back to texture and normals once everything else is working.
You’re going to have two main tasks: build the geometry and update the positions.
For building the geometry, the elegant way would be to use ExtrudeSpline and have it copy the various attributes into buffers. That won’t help with the updating since it’s doing everything in the protected calculate method. So copy pasta starts sounding pretty reasonable. I’d build the initial geometry in a straight line and then try modifying the positions with a simple linear transformation. Once you get that working then you can look at transforming each slice based on the spline’s path.
It’ll be a little work.