[Algorithms] VIPM, VDPM, ROAM questions

[Christopher H. <chu...@ca...>]

Hi all,

Thanks for taking time to read and answer my questions.  I am playing
around with understanding Hoppe's and Bloom's papers on Progressive Meshes
and I have a few questions.

1. For VIPM, is it worth it to write your own implementation, or should I
just use the interfaces that come with D3D?  I imagine this is not a
simple question to answer but probably depends on the situations, so as an
aside which problems do the D3D implementations work best on and which
should be specialized?

2. I am trying to play around with terrain generators (seems like a lot of
newbies often begin here).  I think I like the idea of VIPM or VDPM when
it comes to terrains b/c you are not restricted to height fields and can
have overhangs and caves and the likes.   Which makes me lean away from
ROAM.  But what am I going to give up going V*PM over ROAM?  

3. Also, what is the general consensus on breaking up the terrain into
multiple VIPMs and rendering each at different LoD compared to trying some
VDPM method? (I haven't seen too much on VDPM if anyone has any references
I would appreciate that, the archives don't have too much).  I have seen
tons on the chunked VIPM and I think that it might be worth it, but I'd
like to get your opinions.

4. I guess this question depends on the answer to (1), if I should write
my own VIPM.  I read some emails about improvements to VIPM using
skipstrips or sliding windows.  Has there been anymore talk about these?
I have been thinking about the sliding window and it seems for some things
(trees, rocks, animals) which have many instances it should be a big win.
What have others seen?  

Again, thanks in advance for your help.

Chris