jnkramer3 Jan 28, 2011 at 11:07 PM I am trying to get ideas/algorithms to address the following.  Any help is highly apprehended. I have a simulation with 0 to many shapes and in the middle I need to add a new shapes. The hard part is where can I place it.  It must not overlap with other shapes in the simulation. So, this results in two questions.  Does anyone have any experience/thoughts on a efficient algorithm for this.  I know I could do some sort of random or brute force but I don't like either of those. The second questions, is there any support in Farseer 3.2 for checking if two shapes overlap?  I believe that any algorithm will require this test.   Thanks again.   Jim K. robertdodd Jan 29, 2011 at 10:38 PM When placing the shape, calculate its AABB. ```Transform _transform = new Transform(_position, new Mat22(_angle)); AABB aabb; _shape.ComputeAABB(out aabb, ref _transform, 0);``` Then query the simulator for any bodies that intersect that AABB: ```List affectedFixtures = new List(); World.QueryAABB(fixture => { affectedFixtures.Add(fixture); return true; }, ref aabb); ``` Then loop through each body in that list, then through each fixture in that body.FixtureList, and check for a collision with the fixture's shape: ```Manifold manifold = new Manifold(); Collision.Collision.CollidePolygons(ref manifold, _polygonA, ref _transformA, _polygonB, ref _transformB); ``` Look at PolyCollisionTest.cs in the testbed for an example on colliding shapes.