Tunneling issue; dynamic body with CCD enabled penetrating heightfield collider

[jonlamb-gh]

I'm observing an issue where balls with CCD enabled are penetrating a heightfield collider attached to fixed body.

I'm able to reproduce the issue using the examples3d/trimesh3.rs example on master with this patch:

-    let heightfield = HeightField::new(heights, ground_size);                              
-    let (vertices, indices) = heightfield.to_trimesh();                                    

     let rigid_body = RigidBodyBuilder::fixed();                                            
+                                                                                           
     let handle = bodies.insert(rigid_body);                                                
-    let collider = ColliderBuilder::trimesh_with_flags(                                    
-        vertices,                                                                          
-        indices,
-        TriMeshFlags::MERGE_DUPLICATE_VERTICES,
-    );
+    let collider = ColliderBuilder::heightfield(heights, ground_size);
     colliders.insert_with_parent(collider, handle, &mut bodies);

     /*
      * Create the cubes
      */
     let num = 8;
-    let rad = 1.0;
+    let rad = 0.1;

-    let shift = rad * 2.0 + rad;
+    let shift = rad * 3.0 + rad;
     let centerx = shift * (num / 2) as f32;
     let centery = shift / 2.0;
     let centerz = shift * (num / 2) as f32;

-    for j in 0usize..20 {
+    for j in 0usize..2 {
         for i in 0..num {
             for k in 0usize..num {
                 let x = i as f32 * shift - centerx;
-                let y = j as f32 * shift + centery + 3.0;
+                let y = j as f32 * shift + centery + 6.0;
                 let z = k as f32 * shift - centerz;

                 // Build the rigid body.
-                let rigid_body = RigidBodyBuilder::dynamic().translation(vector![x, y, z]);
+                let rigid_body = RigidBodyBuilder::dynamic()
+                    .translation(vector![x, y, z])
+                    .ccd_enabled(true);
                 let handle = bodies.insert(rigid_body);

-                let collider = match j % 6 {
+                let collider = match 1 { // just balls
                     0 => ColliderBuilder::cuboid(rad, rad, rad),
                     1 => ColliderBuilder::ball(rad),
                     // Rounded cylinders are much more efficient that cylinder, even if the

[jonlamb-gh]

FWIW, I am getting CollisionEvent::Started, followed by CollisionEvent::Stopped on the next sim step.

[jonlamb-gh]

This was remedied by tuning the IntegrationParameters