[ODE] ODE 0.6 and Terrain

[Mark Fournier]

Thanks. I was hoping to use version 0.6 (which doesn't include the heightmap 
code,) rather than get into the live code, so that any changes I have to 
make don't get clobbered when I get fixes for recent bugs, but I'll try the 
current subversion and see how that works out.

----- Original Message ----- 
From: "Megan Fox" <shalinor at gmail.com>
To: "Mark Fournier" <mfournier at artech.ca>
Cc: "ODE mailing list" <ode at q12.org>
Sent: Wednesday, July 26, 2006 3:18 PM
Subject: Re: [ODE] ODE 0.6 and Terrain


>I did what you mentioned, and converted my heightmap data to triangle
> data on the fly.  As you say, this is SLOW.  My solution was going to
> be to modify ODE with a function to let me persist out that pre-baked
> data, to avoid that (very slow) step on future loads.
>
> There is, however, a perfectly good heightmap collider you could use
> too.  I never tried it (I needed holes in my terrain and didn't want
> to modify the heightmap collider to support that), but it has the
> significant advantage that a heightmap can be assumed to be infinitely
> thick underneat - vs the trimesh "paper thin triangle" thing that
> causes so many warping issues.
>
> On 7/26/06, Mark Fournier <mfournier at artech.ca> wrote:
>> I notice that a lot of posters on the mailing list seem to have worked
>> terrain or heightmaps into collision detection, and I'm wondering how 
>> they
>> did it. I'm hoping that, in some cases at least, it wasn't simply the raw
>> conversion of the terrain mesh or heightmap into a trimesh.
>>
>> I had my own system with 0.5 which consisted of converting a heightmap 
>> into
>> a trimesh, but this relied on hybrid trees and a method for saving and
>> restoring a preprocessed mesh (building the trimesh could take up to 10
>> seconds for a 512 x 512 tile heightmap with up to 64 polys per tile, and
>> using other tree types could take up to 20 megs while the hybrid tree did 
>> it
>> in 2 megs or less.) I would like to modify the ODE code so that I can 
>> just
>> submit a heightmap to ODE and have it calculate the polys as needed--this
>> would allow us to have a dynamically changing heightmap.
>>
>> So, if you didn't use pregenerated trimeshes, how did you do it?
>>
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>
>
> -- 
> -Megan Fox
> Idyllon, LLC
> http://shalinor.circustent.us/megan/resume/
>