In the same environment.,the blue box shifts upward while moving forward, and the yellow box stops when it reaches the edge of the ground

Questions
1

In the same environment.,the blue box shifts upward while moving forward, and the yellow box stops when it reaches the edge of the ground
Babylon.js Playground - #BZ92LQ

2

moveWithCollisions() uses an ellipsoid for collision detection. I think that the default ellipsoid doesn’t match the box size, It’s strange because they should act the same.

Try this setting:

box.ellipsoid = new BABYLON.Vector3(0.5, 0.5, 0.5);
box2.ellipsoid = new BABYLON.Vector3(0.5, 0.5, 0.5);

box.showBoundingBox = true;
box2.showBoundingBox = true;

fixes the collision shape. Also, enablePhysics() can be removed since moveWithCollisions() does not use the physics engine.