Hi Jan,

The mesh's vertices are modified by the animation, are they not?  Each
vertex has a weight on it to determine this.  Thus, wouldn't applying an LOD
to it cause a problem in the middle of an animation?

Are you saying I should be able to export two cal3d meshes and then hardwire
the LOD's in?  For example, for a model with a torso, and head;  I'd export
a low-level LOD and high level LOD for both the torso and head.  Then, I
could use some traversing code to stitch the model back into one model?  I'm
just afraid the animation won't allow for the different meshes, but maybe I
under-estimated the code.

Does Blender allow you to export an LOD'd Cal3D model? 


Zach

-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Jan Ciger
Sent: Thursday, March 15, 2007 18:03
To: osg users
Subject: Re: [osg-users] cal3d LODs

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Hello,

Jeremy L. Moles wrote:
> On Thu, 2007-03-15 at 16:23 -0400, Zach Deedler wrote:
>> Hi Jeremy,
>>
>> Yeah, I'm trying to figure out how to create discrete levels of 
>> detail, within the file, and have it animate fluently in the 
>> transition.  Doesn't the cal3d_miniviewer use OpenGL, though, and not
OpenSceneGraph?

miniviewer uses OpenGL (with GLUT, AFAIK). The animation has nothing to do
with LODs, animation will be fluent even through the LOD switch/transition
because the skeleton does not change. What changes is the mesh only. Whether
the change will be visible or not depends on how fine/coarse are your LOD
levels and how is the mesh modelled/textured, not on Cal3D (Cal3D doesn't
actually use this "discrete" model of doing LODs).

Doing LODs on skeletons too is possible, but that is a completely different
issue - how to recalculate the keyframe animations when the skeleton
topology changes? Look up motion re-targeting in Google if you are curious
about the amount of work this requires.

> 
> Well, there are at least two easy-to-use Cal3D OSG NodeKits--one by 
> the guys at Underware (which is GPL) and the other (original) which is
LGPL.
> I'm also working on my own Cal3D NodeKit to do the animation in a 
> vertex shader (which gives me about 500% performance improvement), 
> which I'll hopefully have done soon.

Is this planned to be released as free (as in freedom) software? That would
be mightily cool. I was planning on implementing something like that for a
while already but I never seem to get to it - simply too much workload at
the moment.

> The NodeKit may provide some easy wasy to set the LOD level, but if 
> not--it's a simple method call to setLodLevel().

setLodLevel() works only if you have defined/exported the "collapsible"
LODs that Cal3D can work with. Otherwise it will collapse the mesh in an
unpredictable way which you will certainly not like - such as a head or a
leg of a guy can disappear because Cal3D has no means to distinguish which
edges/faces are more important to preserve than others. The models which
come with Cal3D have this defined OK, that's why it works in miniviewer.

Regards,

Jan
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