[ODE] Trimesh problems

[Jon Watte (ODE)]

A CFM of 1e-8 is pretty darn small for a floating-point value. You can 
only represent about 1e-5 for something that's scaled at "1" with 
floats. I'd try setting CFM to 1e-3 and see how that goes.

Also, ODE isn't perfect. For resting bodies, you really want to turn on 
auto-disable, else they may jitter forever, and the jitter could 
potentially cause energy additions to the system.

The size of the triangles is interesting, though -- might there be some 
force that's scaled by a side length, or un-normalized cross product, or 
something?

Cheers,

			/ h+


Anders Olofsson wrote:
> Hi!,
> 
> In my litte test I have this:
> dWorldSetCFM (world,1e-8f);
> The ERP I dont change, probably some default value.
> 
> Only got 2 triangles in the test, they dont look degenerated! :) (check 
> wireframe)
> 
> True, its single precision, but the spheres that are jumping in the movie 
> is dropped at origin. In the test too. But I'll check this (switching to 
> doubles).
> 
> Thanks for your help!
> 
> --Anders Olofsson
> 
> At 20:00 2006-01-09, you wrote:
> 
>>A few things come to my mind:
>>1. What are the global ERP / CFM parameters set to ? Did you try to
>>tweak them too ?
>>2. Make sure you're filtering out degenerated triangles in your
>>trimeshes, because ODE isn't doing it, and last time it caused some
>>severe bugs in my application.
>>3. My bet: in your video, you seem to have a pretty huge terrain. What
>>scale units are you using ? Are the spheres dropped very far from the
>>origin by any chance ? If so, i do think it's a float 32 precision
>>problem, and you might verify this easily by switching ODE to double mode.
>>
>>Cheers,
>>
>>F. Brebion
>>
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> 
> 
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