[Algorithms] Understanding VIPM's

[Chris B. <Chr...@ma...>]

I was going to send this e-mail directly to Mr Bloom for help but thought that other lurkers here might be able to benefit from the answer I receive. 

I've been reading Charles Bloom's website documentation of VIPM's and am starting to get a little more excited about them now that I realise how much it can simplify the rendering pipeline amongst other things...

I have some question's though:

-From what I've read I believe that the VIPM mesh would resemble something along the lines of a Triangulated Irregular Network that is locked to a grid. I don't however understand the edge collapsing and vertex insertion routines. I understand the error array that would come with each patch(chunk) but just not what to do with it.

-The other thing I don't understand is the edge matching for terrain chunks. Under something like a triangle or quad ROAM implementation the edge mapping is easy to visualise but I cant quite grasp how the edges get formed.  Does the chunk start at minimum resolution, ie a square then get built up as the error is implemented and the surface subdivided. If this is so at what point is an edge broken. 

If anyone is interested in helping me understand this I'm happy to write up a pretty graphical document that'll explain all this to other people new to the technique (partly so you guys don't have to answer the question again, partly so I know I understand the technique properly).

Many thanks


Chris Brodie