Hi,

I am hoping someone can help me with this. I am working on a very simple setup for Houdini 18 RBD workflow. Everything is working as intended until I manipulate the “active” attribute.

My simple intention is to make a part of the object active and a part - not. Normally (in older workflows), the part that it active will participate in the simulation. But from what I am seeing now it looks like even if one piece of an object is inactive, the whole object becomes inactive.

On the solver when I visualize the active part, it shows correctly that only a part of the box is active. But when I run the sim, the whole object is inactive. I have to set the whole object to active to make it work.

I am sure I am missing something very small…

You can see the scene file here https://hdbp.io/SjLaQ1IB [hdbp.io] or in attachments

Thank you!

hmm…that's annoying isn't it ?…reading the helpcard…you should be allowed to make only group of an object active but seems like active/nonactive applies to whole object.

RBD Configure SOP
The RBD Configure SOP lets you set up properties individually for different sets of RBD objects. The Group parameter allows you to select a group of pieces (such as wood pieces) and set up whether they're Active, Animated, Deforming, or Sleeping.

workaround for me right now is to pin part of an object, that works.

The problem in this example is that you have active objects constrained to inactive objects. If you don't plug in the middle wire, (constraints), it works. In your example, there are no forces to break the constraints.