In the template scene, climbing the cubes is very steady and stable, because the hands could reach deep inside the cube and still grab hold of it.
But when i imported my own objects to climb, i am only able to grab hold of the outer surface skin, a very thin peripheral area of the object. If my hands reach deeper into the object, it is not able to grab hold of it and i will fall down from my climb.
How to make any object “deeply grabable” just like the climbing cubes in template scene?