Maintain particle rotation on moving mesh

Support Particles and Physics Simulations
1

Hi there,

In this picture, the teeth of this dune-inspired take on a purple worm (D&D) are distributed via a particle system as I like them. I get the best results using the normal-tangent orientation axis setting, under particle rotation.

Wormling01 okay
Wormling01 okay1920Ă—1080 265 KB

However, when I move to another frame in the animation (the worm is moved by an animated armature), the alignment of the teeth goes to pot. How can I fix this so that the original alignment is maintained?

Wormling02 jank
Wormling02 jank1920Ă—1080 267 KB

Interestingly, altering the phase slider and then resetting the alteration to 0 (particle system ==> rotation ==> phase) resets the teeth to their desired rotation, regardless of frame number!

I’m far from an expert on particle systems. However, during my research on YouTube whilst trying to solve this myself, I watched this video. It made me aware that the normal-tangent orientation axis looks to the UV map of the emitting mesh (hope I have that right). The next pic shows how the mesh is unwrapped, should that be relevant.

Wormling03 UV seam
Wormling03 UV seam1920Ă—1080 281 KB

Thanks for your time! :slight_smile:

2

Hi,

check the box “Regrow” shown in your first picture. This forces the particle system to check everything for every frame change. And than maybe try normal instead of normal tangent. Makes more sense to me when I see this. And do not enable “global coordinates”, “Object rotation” and “Object Scale” (under >Render>Object in Prticle settings. Play with these settings and it should work or you find a way it works for you. Btw. make shure that the teeth original geometry is oriented the way that it points to the positiv y- direction. And Transformes are aplied. One last thing is to check if you enabled “use modifier stack” under “Emission > Source” in particle settings.Just in case You use a subdiv mod ore sometihing before the particle modifier. Hope it helps …

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3

Brilliant Fred, you cracked it with your first sentence. Thanks for your help. :slight_smile: Case closed!

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