This question is not strictly related to Mechanical Engineering, it's more Industrial Design I guess, but maybe some of you know the answer. I got puzzled for the last few days with an overturn check, and decided to ask for help online. I used to do an analysis for for overturning effect of chairs and tables, by hand based on 2d support walls overturn check from the structural engineering. This is an example of bench: ("A" point represents the reference point for overturning) Overturn condition: F1 * l1 ≤ 1.5 * F2 *l2 But what should I do when the objects are not planar (planar but extruded in third dimension like this bench)? Here is an example of a 3d irregular shaped object: It is not possible to check for overturn this kind of irregular shaped object by hand. Because forces no longer lie in the same plane: Some other combinations: here is .3ds file of this object: http://www.mediafire.com/?qxx7gqp1ndt9s6x Can anyone help me with this issue? How to check objects for overturn, when their overturn moments do not lie in the same plane? Thank you for the reply.