Questions on Collisions and Culling

bool Vehicle::updateCollision(F32 dt)
{
   // Update collision information
   //MatrixF mat,cmat;
   //mConvex.transform = &mat;
   //mRigid.getTransform(&mat);
   //cmat = mConvex.getTransform();

   mCollisionList.count = 0;

   //CollisionState *state = mConvex.findClosestState(cmat, getScale(), mDataBlock->collisionTol);
   //if (state && state->dist <= mDataBlock->collisionTol) {
   //   //resolveDisplacement(ns,state,dt);
   //   mConvex.getCollisionInfo(cmat, getScale(), &mCollisionList, mDataBlock->collisionTol);
   //}

   Box3F box = mConvex.getBoundingBox(getTransform(), getScale());
   F32 len = (mRigid.linVelocity.len() + 50) * dt;
   F32 l = (len * 1.1) + 0.1;  // fudge factor
   box.min -= Point3F(l, l, l);
   box.max += Point3F(l, l, l);

   ConcretePolyList polyList;

   CollisionWorkingList& rList = mConvex.getWorkingList();
   CollisionWorkingList* pList = rList.wLink.mNext;
   while (pList != &rList) {
      Convex* pConvex = pList->mConvex;
      if ((pConvex->getObject()->getType() & StaticObjectType) != 0)
      {
         Box3F convexBox = pConvex->getBoundingBox();
         if (box.isOverlapped(convexBox))
            pConvex->getPolyList(&polyList);
      }
      pList = pList->wLink.mNext;
   }

   ConcretePolyList::Poly* ps = polyList.mPolyList.begin();
   ConcretePolyList::Poly* pe = polyList.mPolyList.end();
   for (; ps != pe; ps++)
   {
      if (mCollisionList.count < CollisionList::MaxCollisions)
      {
         float dist = ps->plane.distToPlane(mRigid.linPosition);

         if (dist < mDataBlock->radius && dist > -mDataBlock->radius)
         {
            if (ps->vertexCount > 2)
            {
               bool inside = true;
               Point3F v = ps->plane.project(mRigid.linPosition);

               for (U32 i = 0; i < ps->vertexCount - 1; i++)
               {
                  U32 i0 = polyList.mIndexList[ps->vertexStart + i];
                  U32 i1 = polyList.mIndexList[ps->vertexStart + i + 1];
                  Point3F p0 = polyList.mVertexList[i0];
                  Point3F p1 = polyList.mVertexList[i1];

                  VectorF q;
                  mCross(ps->plane, p1 - p0, &q);

                  if (mDot(q, v - p0) >= 0.0f)
                  {
                     inside = false;
                     break;
                  }
               }

               if (inside)
               {
                  Collision& info = mCollisionList.collision[mCollisionList.count++];

                  info.point = v;
                  info.normal = ps->plane;
                  info.material = ps->material;
                  info.object = ps->object;
                  info.distance = 0.0f;
               }
            }
         }
      }
   }

   // Resolve collisions
   bool collided = resolveCollision(mRigid,mCollisionList);
   resolveContacts(mRigid,mCollisionList,dt);
   return collided;
}