It all started when two meshes in the project I am doing would only show an intersection when they were overlapping by several units. Rather than try to explain the steps needed to reproduce what was happening in the project I thought I would see what happened in the playground. Now I must have done something stupid because box1.intersectsMesh(box0, false)always read true whatever the positions of box0 and box1. My trial is at http://www.babylonjs-playground.com/#MABFZ I have tried it with and without setting checkCollisions for the meshes and the scene. Waiting to kick myself when someone points out what I have done wrong.