I have particles following a curve guide and a collision physics modifier added to a cube with "kill particles" activated. I have the permeability of the cube keyframed so that when the artery closes, the permeability is at "0" and when the artery is open, the permeability is at "1". Can anyone give me an idea of why I am having these problems in the final render? they don't show up in the viewport.

Video of what is happening: https://www.youtube.com/watch?v=XzUokN3JfgA

Screenshot of the cube: enter image description here

enter image description here

  • $\begingroup$ I think this post would be a bit clearer if you opened with a simple statement of your intent, something like: 'I want to obstruct passage of particles when the vessel is closed'.. if that's the case. $\endgroup$
    – Robin Betts
    Commented Mar 9 at 9:07

1 Answer 1


Have you set keyframes for the permeability of the collision?

The permeability should also be set to zero when eliminating particles.

Or have you not rebaked the particle system?

  • 1
    $\begingroup$ I guess this (although giving a possible solution) is rather a comment asking for clarification then an answer. But maybe it helps so just leave it here. Apart from that, regarding the possible solution: as I understand the setup, the artery should kill the particles when it is closed..? And in this case permeability is 0 according to the question. Probably I just don't understand the setup. $\endgroup$ Commented Mar 8 at 13:28
  • $\begingroup$ @iskanime Yes I have the permeability keyframed. I've included a picture of the permeability keyframes at the bottom of the post now. I am new to particle emitters. What is the rebaking of the particle system workflow? Up until now I haven't heard anything about this. I can also send a link to the project files of you would like to have a look at it yourself! Thank you guys for responding! $\endgroup$
    – Stengy02
    Commented Mar 8 at 18:10
  • $\begingroup$ @GordonBrinkmann I can also send you the project files if you would like! Thanks again! $\endgroup$
    – Stengy02
    Commented Mar 8 at 18:16
  • $\begingroup$ @Stengy02 Yes, I think it's necessary to upload the project files. That way, it will be easier to identify any issues. $\endgroup$
    – iskanime
    Commented Mar 9 at 15:23
  • $\begingroup$ @Gordon Brinkmann Thank you! I'm not very familiar with StackExchange yet. Yes, this answer might be more suitable in the response. $\endgroup$
    – iskanime
    Commented Mar 9 at 15:30

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