# [ODE] Problem with collisions

João Pereira joaopedro17 at netvisao.pt
Thu Oct 4 07:13:16 MST 2007

```Hello,
Im new to ODE and started working with it because i have a project on my
University that need it.

Im trying to start with a simple example a ball falling and a plane.
When the ball hit's the plane should get up again.

do i need a space collision to get this done????

I have created a simpleSpace and the ball just go through the plane and
keeps falling.

i created the ball has

typedef struct ic3dPos{
dReal x;
dReal y;
dReal z;
}ic3dPos_t;

typedef struct icBody{
dBodyID bId;
dGeomID gId;
ic3dPos_t pos;
dMass mass;
}icBody_t;
#define sphereMass 0.5

icBody_t ball;
icBody_t floor2;
dSpaceID space;

ball.bId = dBodyCreate( world );
pos = (ic3dPos_t *) dBodyGetPosition( ball.bId );
ball.gId = dCreateSphere( space , sphereRadius );

ball.pos.x = 0;
ball.pos.y = 0;
ball.pos.z = 10;

dBodySetPosition( ball.bId , ball.pos.x , ball.pos.y , ball.pos.z );

//set's the mass parameters
dMassSetSphereTotal(&ball.mass , sphereMass , sphereRadius );
dBodySetMass( ball.bId , &ball.mass );

and the plane has

floor2.gId = dCreatePlane( space , 0 , 0 , 1 , -1 );

do i need to do something to make the ball go up when its the plane????

Thanks for the help

João Pereira

```