[ODE] Setting up two objects with two seperate centre of gravities

[Jon Watte (ODE)]

You're not actually assigning the mass to the body in that code.

Cheers,

          / h+


Tristan McMillan wrote:
> Hi ODE Community
>
> This question has had me stumped for quit a while now.
>
> What I'm trying to do is create a truck and trailer combination. So I've
> created two bodies:
> 1) Body 1 is connected to a Trimesh geometry which represents the horse
> 2) Body 2 is just a box.
>
> However the problem comes when I try to setup the mass and inertias of
> each body.
>
> I currently do this using the following function.
> Horse (Trimesh):
>
> dBodySetPosition( horseBody, horseCG[0], horseCG[1], horseCG[2] ); 
> dMassSetParameters(&mM,mass,CG[0],CG[1],CG[2],Ix,Iy,Iz,0.0,0.0,0.0); 
>
> Trailer (Box)
>
> dBodySetPosition( trailerBody,trailerCG[0],trailerCG[1],trailerCG[2] );
> dMassSetBox( &mM, DENSITY, length,width,height);
>
> Where the CG positions are all relative to a global reference system. 
>
> This however always gives an error for the horse setup:
>
> ODE Message 2: center of mass inconsistent with mass parameters in
> dMassCheck() File mass.cpp Line 68
>
> ODE Message 2: center of mass inconsistent with mass parameters in
> dMassCheck() File mass.cpp Line 68
>
> Is this the right way to set the mass of a trimesh body?
>
> I've checked the wiki and found that the cg of each body should always
> be at the origin, but then how do you place the other body (trailer)
> relative to this?
>
> BTW: The trailer is connected to the horse using a universal joint.
>
> Thanks
> Tristan
>
>
>
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