[ODE] Sphere vs trimesh problem again :(

[Jaroslav Sinecky]

I hope there's not some new bug in the sphere-trimesh collision (after 
my "improvements"). But all testcases work fine, which suggests, there's 
a problem in your code.
Just a first idea: could you just try to swap the order 2nd and 3rd 
vertex in each trimesh triangle (or indices) and submit it to ode 
without explicit normals (which I think don't work).

Jaroslav


Peter Libič wrote:
> Hi,
>
> I'm trying to write something like test_buggy on the trimesh terrain.
> So I copied most of code that creates buggy in the test and tried to 
> drop it on trimesh terrain.
> But the "wheels" are fallin down through terrain.
> Small viedo is here (122K) : http://www.ptus.sk/petko/tst.avi
> The small cubes in corners are wheels - their geom is sphere, i only 
> don't have something to draw asphere yet.
> If I change the spheres to boxes, everything seems to be OK.
>
> I'm using dWorldQuickStep with time 0.01s, but dWorldStep results in 
> same behaviour.
> Normals of the trimesh are pointing up.
>
> Compiled with ODE from svn trunk with vs2005 and double precision.
>
> Here's body creation code:
>
>     dBodyID bID= dBodyCreate( sim->mODEWorld );
>     GLVector3d pos = we->getPosition();
>     dBodySetPosition( bID, pos.x, pos.y, pos.z );
>     GLQuaterniond rot = we->getOrientation();
>     dQuaternion quat;
>     quat[0] = rot.getW();
>     quat[1] = rot.getV().x;
>     quat[2] = rot.getV().y;
>     quat[3] = rot.getV().z;
>     dBodySetQuaternion( bID, quat );
>
>     dMass m;
>
>     dMassSetBox (&m,1,len,wid,hei);
>     dMassAdjust (&m, 1);          dBodySetMass (bID,&m);
>     dGeomID gID = dCreateBox( sim->mODEOtherSpace, len, wid, hei );
>     dGeomSetBody (gID,bID);
>
>
>         // wheel bodies
>         dBodyID wheel[4];
>         dGeomID wgeom[4];
>         for ( int i=0; i<4; i++ )
>         {
>             wheel[i] = dBodyCreate( sim->mODEWorld );
>                       dMass mass;
>                   dBodySetQuaternion (wheel[i],quat);
>
>             dMassSetSphere (&mass,1,WHEEL_RADIUS);
>             dMassAdjust (&mass,1);
>             dBodySetMass (wheel[i],&mass);
>
>             wgeom[i] = dCreateSphere ( sim->mODEOtherSpace, WHEEL_RADIUS );
>             //wgeom[i] = dCreateBox( sim->mODEOtherSpace, 2,2,2 );
>             dGeomSetBody( wgeom[i],wheel[i] );
>         }
>
>         dBodySetPosition( wheel[0], pos.x + len / 2 , pos.y + wid / 2, 
> pos.z - hei / 2 );
>         dBodySetPosition( wheel[1], pos.x + len / 2 , pos.y - wid / 2, 
> pos.z - hei / 2 );
>         dBodySetPosition( wheel[2], pos.x - len / 2 , pos.y + wid / 2, 
> pos.z - hei / 2 );
>         dBodySetPosition( wheel[3], pos.x - len / 2 , pos.y - wid / 2, 
> pos.z - hei / 2 );
>
>
>         //wheel hinges
>         dJointID joint[4];
>         for ( int i=0; i<4; i++ )
>         {
>             joint[i] = dJointCreateHinge2( sim->mODEWorld, 0 );
>             dJointAttach (joint[i], bID, wheel[i] );
>             const dReal *a = dBodyGetPosition ( wheel[i] );
>             dJointSetHinge2Anchor(joint[i],a[0],a[1],a[2]);
>             GLVector3d rot_axis = we->getOrientation().rotateVector( 
> GLVector3d( 0, 1, 0 ) );
>             GLVector3d susp_axis = we->getOrientation().rotateVector( 
> GLVector3d( 0, 0, 1 ) );
>
>             /*
>             dJointSetHinge2Axis1(joint[i],0,0,1);
>             dJointSetHinge2Axis2(joint[i],0,1,0);
>             */
>
>             dJointSetHinge2Axis1( joint[i], susp_axis.x, susp_axis.y, 
> susp_axis.z );
>             dJointSetHinge2Axis2( joint[i], rot_axis.x, rot_axis.y, 
> rot_axis.z );
>         }
>
>         // set joint suspension - if uncommented this, nothing improves
>         /*
>         for (int i=0; i<4; i++)
>         {
>             dJointSetHinge2Param (joint[i],dParamSuspensionERP,0.4);
>             dJointSetHinge2Param (joint[i],dParamSuspensionCFM,0.8);
>         }
>         */
>
>         // lock wheels along the steering axis
>         for (int i=0; i<4; i++)
>         {
>             // set stops to make sure wheels always stay in alignment
>             dJointSetHinge2Param (joint[i],dParamLoStop,0);
>             dJointSetHinge2Param (joint[i],dParamHiStop,0);
>         }
>
>
> And here is contact creation code:
>             contact[i].surface.mode = /*dContactBounce |*/ 
> dContactSoftCFM;   //uncomenting bounce doesn't help
>             contact[i].surface.mu = 0005;
>             contact[i].surface.mu2 = 0;
>             contact[i].surface.bounce = 0.5;
>             contact[i].surface.bounce_vel = 0.0;
>             contact[i].surface.soft_cfm = 0.01;
>
>             dJointID c = 
> dJointCreateContact(sim->mODEWorld,sim->mODEContacts, &contact[i]);
>             dJointAttach
>             (
>                 c, 
> dGeomGetBody(contact[i].geom.g1),dGeomGetBody(contact[i].geom.g2)
>             );
>
> Anyone any suggestions?
> Tahnks a lot,
>
> Petko
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