[vtkusers] Recent vtkAssembly Changes

[John Biddiscombe]

I have a custom vtkAssembly subclass which slices terrain data
into 1km tiles, creates a mapper and applies a texture to each
piece, combining the lot into a nice assembly.

After doing a CVS checkout, it no longer works, and I need to
supply an "Update" method so that it will rebuild itself when the
terrain (or images) are changed.

Previously I overrided RenderOpaqueGeometry (which was a kludge in
my view) and I'm tempted now to override UpdatePaths as this gives
me a perfect opportunity to rebuild my assembly. Is there a
correct place to intercept the update mechanism and if so, why no
virtual methods?

If I've understood the chain of events alright, then I'll make
UpdatePaths virtual and use that. OK?

John B