I'm trying to make molecular add-on particles to interact with other rigid bodies and it appears that they can interact with an animated rigid body, but not with non-animated rigid body. Does that make any sense or I'm doing something wrong?

As soon as I'm animating the glass jar and move it with the keyframes, the particles are moving along in it (strangely squeezing into one corner and each other due to the gravity, but then distribute evenly again when it stops, but that's not my current issue), but as soon as I remove the animation and try to tip over that jar with a cube, they stop interacting with the jar and stay in one place, while the jar falls over.

I read people are rather having the other way around issues, does anyone have the expertise to see what's wrong there?

Thank you in advance!

  • $\begingroup$ I have to login to view your file (what if i can't or don't want to?) You might want to consider using the file sharing site especially for this Blender StackExchange. It's over here: blend-exchange.giantcowfilms.com $\endgroup$ – Fjoersteller Jul 7 '20 at 20:12
  • $\begingroup$ Hi Fjoersteller, I'm sorry that was unintentional, I thought I've shared the file properly. And thanks for the file sharing service tip, done! $\endgroup$ – Levon Dombayan Jul 8 '20 at 8:50

It seems like some cache conflict.

enter image description here


  • The glass jar should be Physics Properties > Rigid Body > Collision > type Mesh (not Convex because it should behave like filled object, but it didn't, hmm ...)
  • it is always better to Apply Scale (Ctrl+A) to avoid weird behaviour of boundaries
  • only make a difference if Substeps is changed from 4 to 1
    (but changing it back to 4, it explodes in some point of anim, because of some previously cached data, that I'm not able clear from file even I change amount of particles, that always helped in crisis like this.

Bake to Keyframes

What I can recommend is to select glass jar and Bake to Keyframes (if you played all animation so rigid body was cached, baked avoids caching RB. Since than I don't have an issue with molecules.

Also it solves cube (that is pushing the glass) to affect particles.

enter image description here

After bake you can use Decimate function (with cursor hovering in Graph Editor) to simplify F-curve.

enter image description here

  • $\begingroup$ Hi mate, thank you for your suggestions! Though it's getting even more interesting. Not sure why, your bake was working fine as expected. As soon I freed the bake and baked again with the exact settings you made, the particles again stay in their place while the glass bowl tips over. $\endgroup$ – Levon Dombayan Jul 8 '20 at 10:11
  • $\begingroup$ vklidu, could you please advise the sequence of bake I should do? I'm baking the rigid world first, then baking the molecular addon. Is that how you baked your version? $\endgroup$ – Levon Dombayan Jul 8 '20 at 10:23
  • $\begingroup$ No, I baked only Molecular, by baking RigidBody World became baked Molecular as well but in very weird way. $\endgroup$ – vklidu Jul 8 '20 at 10:33
  • $\begingroup$ Okay... Tried that too. Very strange. $\endgroup$ – Levon Dombayan Jul 8 '20 at 10:40
  • $\begingroup$ Sorry mate, what's your Blender version? Mine is the official 2.83.0 $\endgroup$ – Levon Dombayan Jul 8 '20 at 10:47

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