[ODE] vector has zero size
Wouter Mollemans
wouter.mollemans at gmail.com
Wed Oct 18 05:20:23 MST 2006
Thx I will try to use your solution, but this is of course only a work
around. Does anyone has an idea what causes these infinite values?
Is it the collision detection algorithm? I noticed that the collision
algorithm (dCollide()) frequently reports a NaN value for the position
value of the first contact (contact[0]).
Alex Green wrote:
> Apporx once every 12000 simulations I get the same error. The error can
> be detected. I run a function called 'checkPhysicsForError()' per frame.
> It works as follows:
>
> bool checkPhysicsForError(void){
> dReal *pos = (dReal*) dBodyGetPosition(bodyID of one of my boxes);
> if(!(pos[0]==pos[0]) || !(_finite(pos[0])))
> {
> dWorldDestroy(world);
> reset all my stuff
> create everything again;
> rewind one test (ie do the one that failed from the beginning);
> return true;
> }
> else return false;
> }
>
> Notes:
> pos[0] == pos[0] checks for NAN (not a number);
> _finite() is windows, is there a cross platform check?
>
> Cheers -alex
>
> Wouter Mollemans wrote:
>> After some debugging, I noted that some of the collision points are
>> lying at infinity. This causes dNormalize4() to go nuts. Has anyone
>> seen this problem before and do you know what causes this effect?
>>
>> Greetz
>> Wouter
>>> Hi,
>>>
>>> In my simulator I try to fit two rigid objects into eachother (a
>>> little bit like a 3D puzzle). The rigid objects are trimeshes
>>> (around 4000 triangles) and all my joint are of the type contact.
>>> Sometimes this works nicely, but mostly I get following message: "ODE
>>> message 2 : vector has zero size" emmtted by dNormalize4().
>>> Consequently the velocity becomes Nan and my simulation is ruined.
>>>
>>> Is there a solution? Is there a maximum number of triangles that can
>>> be used or what is the source of the error?
>>>
>>> Thanks
>>> Greetz
>>> Wouter
>>>
>>>
>>> --
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>>
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