Rigid Body Tag
-
Hello,
Has the Rigid Body tag been changed in the latest release?
I have an object (which is a collection of a few objects grouped into a null) and I need it to fall to the ground. However it isn't working. I have done this before with the same kind of object and I think I had to change to 'Moving Mesh' but I don't see it anymore?
Kind Regards
Dave -
Hi Dave,
Please use a Fracture Object instead of the Null.
The Collision Tab> Hierarchy Merge Level
can be used to have them work individual or as a group.Please let me know if that works for you.
All the best
-
Hi Dr Sassi,
Thanks so much, that worked
Are you supposed to set the hierarchy level according to how many objects you have that you want to act as one? Initially my object broke up. It's made of three objects so I set that level to three and it worked.
Just one more question if I may? This is actually for a still scene, I just want some objects to fall to the floor and stay still where they land. I set the friction, bounciness and stickiness to zero but they still slide around the floor after they have landed. What else do I need to set to make them drop and stay still where they land? Many thanks.Kind Regards
Dave -
Hi Dave,
Thank you for the feedback
The hierarchy level allows all objects to react as one or separate. Please have a look here:
(under the three chairs)
https://help.maxon.net/c4d/2026/en-us/Default.htm#html/TRIGIDBODY-RIGIDBODY_PBD_COLLISION_GROUP.html#RIGIDBODY_PBD_INDIVIDUAL_ELEMENTS_MERGE_LEVELThe simplest way would be to cache them (inside the Rigid Body), then find your best position, and while the Fracture object is active, use the Object Manager> Object> Current State To Object command. This creates a copy of the Fracture result for this specific frame. Which means you can set the Fracture to invisible, or via Layers to off. If you change your mind, all is available.
Let me know if that works for you.
All the best
-
Hello Dr. Sassi,
I had the same question, and it works for me with the Fracture object. However, I now have the problem that the Rigid Body does not remember the initial state as soon as I go from 0 to 1 in ‘Summarise hierarchy’.
Is this a bug, or am I overlooking something?EDIT: The initial state is saved, but only activated from frame 1 onwards, which is unfortunately a problem for my project. I would be grateful for any tips.
Many thanks and best regards,
Daniel -
Hi Daniel,
The first suggestion, assuming the parent is mandatory for your setup, is to expand the project for a moment to frame -1 (if it otherwise started with Frame zero) and "Set Initial State" to -1. Then set the project time back to frame zero.
Alternative: set at frame zero for each object a keyframe (PSR), which the Rigid body tag will ignore. If you enable Forces> Follow Position/Animation, this will no longer be ignored, but you want to have it anyway there.
The key question is, why not have on each child object a single Rigid Body tag? While a Selection object allows for selecting all at once and changing parameters in one step, as would be possible with a single object. However, the Collision Shape could be more optimized, that way.
All the best
-
Hi Dr Sassi,
Thanks again, I used your suggestion for stopping them where I liked where they fell and froze them and got my project done
Howvere I noticed something strange on one occasion (I did the same thing with a few different scenes) On one of them, I cached it and stopped on a frame where I liked it, but I forgot to do current state to object. When I rendered out the current frame, it was a different one to the frame I stopped at in the timeline. Why would that be? It's not a problem since I got my project done but I'm curious, so I understand whats happening.Kind Regards
Dave -
Hi Dave, you're very welcome!
There are many reasons.
Caching defines a specific state per Frame; hence, you can move the time slider back and forth, while the same frame number will show the content equally.
The caching provides the data to the beginning of the frame calculation, whereby otherwise non-cached data might get to a calculating state later during that Frame.
So, when you move back and forth with a non-chached scene, the results that you see in the editor view are not reliable. Why is that? The simple answer is – to be able to work in the editor view – one wishes after each little action to see the results of the given input. This requires refreshing the scene (like pressing the A key shortly).
Which means the Calculation Hierarchy (see -> Priority) is run through each time, perhaps even updating with newer data. Newer Data? If an object is not well-positioned in the object manager (or set up with a proper Priority, if possible), it might (or not) take the data that is from a previous frame, as the newer data is not calculated yet. If that is perhaps not one case, and the chaos of a setup is large, delays of many frames can happen. Which means the outcome is different. If the editor is updated over and over again, those delays are perhaps not noticeable.
When it comes to render time, here the calculation is only a single action, with no exception, and is run through a frame to create results once! Then the next Frame. Here is the huge difference. The editor view and the render view might or might not match. The preview render is always a good idea to find those setup problems early on. Caching an object provides the data (again) at the beginning of the Frame, and avoids a Priority problem typically.
More about this:
https://help.maxon.net/c4d/2026/en-us/Default.htm#html/TTARGETEXPRESSION-OBASELIST.html#prioIf that was the reason for your result, I'm not 100% sure, of course, how can I know? I don't know your setup.
Anyway, I hope that helps.
Cheers
