Hi,

I'm learning Houdini and I want to create a box pushing other smaller boxes as it travels.
I've used RBD Object on both the Geo.
How do I edit the Collisions to make it fit with the geo? At the moment, when I Show Collision Guide Geometry its not tightly fitting the geo.

Thanks

First of all, your “Moving_rock” node must be “static object” , not “RBD obj” , because the box is keyframed and should not get affected by gravity or other forces .
then dive into “Auto dop network” and choose “Moving Rock” node (which calculate now as static obj) and in parameter pane, enable “use deforming geometry” , this option recall the position of object in every frames and not just the first frame .

finally, you need to consider the “Rocks” node as “RBD fractured” , because you have lots of rocks which needs to simulate individually .