[ODE] Box/Trimesh contact filtering and oblong geoms

[Rodrigo Hernandez]

That sounds like it should be changed to EPSILON, either FLT_EPSILON, 
DBL_EPISILON or an aproximation if float.h is not available.
There is no check for EPSILON on the configure script, but I could 
easily add it to autotools, could you try changing your test 0 for an 
EPSILON and see what happens then?

Thanks.

Julien LOLLIVIER wrote:

>Hi,
>
>I've noticed something strange between vanilla ODE 0.5 and "recent" CVS snapshots : small oblong geoms (my rockets, for example) are totally unstable, and tends to explode with CVS version, but are very stable with ODE 0.5.
>
>After a long digging, i think the problem comes from GenerateContact (ode/src/collision_trimesh_box.cpp). This function tries to detect duplicate contacts, searching for unique position and normal, doing this:
>
>// same position?
>for (int j=0; j<3; j++)
>   diff[j] = in_ContactPos[j] - Contact->pos[j];
>if (dDOT(diff, diff) < 0.01) 
>   { ... }
>
>Is this 0.01 empirical ? With this value, 75% of my contacts were deleted.
>
>A good value for my applications is ... 0 :
>if (dDOT(diff, diff) == 0)
>   { ... }
>... removing only few contacts, and allowing stable rockets and boxes.
>
>What about changing this value (or providing a way to change it at configure time) ?
>
>--
>Additional infos:
>today (2005-04-26) CVS version,
>single precision, release mode, under Linux,
>rocket sizes : (0.279062,0.058227,0.053364)
>
>--
>Julien 'Xfennec' Lollivier,
>CQFD Corp. - Quiris
>http://raydium.cqfd-corp.org/
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>
>  
>