this is my first post in the forum after digging countless ways on how to get this solved. I hope you can help, appreciated.

Attached here is the link to my video, you can see that the first 24 frames of my OBJ sequence, the emitted spheres went through and do not bounce. Only at frame 25 when my OBJ sequence stop moving, then they bounce. I wanna create a rain scene so it would look bad if the rain drops do not touch the scanned couple.

YouTube Video Link

My second question is, if I need to make this couple becoming a body fire / smoke, I need Blender to understand / treat this OBJ sequence as a single object animation. Would there be any magic way to accomplish this? I heard of Wrap4D but it does not give desire result (yet).

It just goes through my model

Please help me out and thanks for your time.


  • $\begingroup$ Do you have collisions (Inside the particle tab) enabled on the animated OBJ? $\endgroup$
    – Jakemoyo
    Apr 16, 2022 at 11:38
  • $\begingroup$ Yes I did active the collisions for the OBJs sequence. If I place a rigid body plane above, it will fall and collide with my object. But it's not happening with emitter objects. :( $\endgroup$
    – Hai Bac
    Apr 16, 2022 at 11:50

1 Answer 1


Using an animated .obj sequence as input for dynamic collision simulations is, as far as I know, not possible.

The .obj sequence has no information about motion in that sense, these are just static models as far as Blender simulations are concerned. You need motion information that Blender simulations can understand and react to.

The only solution I can think of is unfortunately to build proxy models, and recreate the animation using a regular animated models in Blender. If you don't need very precise collisions and can fake a lot of it in the renders and lighting, you could work with primitives that act as colliders and animate those. Then you'd just hide the primitives in the final render. That should be doable.

If you need high accuracy then you're basically completely recreating the scans, because then you have to model the characters, create rigs, animate them and generally just do a ton of work.

Good luck, hopefully you'll find a better solution!

  • $\begingroup$ Creating a primitive and manually place it according to my scanned model is what I think of initially. That would be fine for wide shot but when moving into close-up shots, that would be an issue. Do you think there is any solution that works just like Wrap4D so it will detect my mesh, wrap it nicely just like a thin plastic film (just like food wrapper?). Thanks for your inputs, I really appreciate yours. $\endgroup$
    – Hai Bac
    Apr 17, 2022 at 10:20
  • $\begingroup$ Just had a look at Wrap4D and that looks like just the right software for the job, but as you're saying it does not give the desired results, I think there might not be an automated solution with high enough quality. You could try Deepmotion, you get 30 seconds for free which should be enough for evaluation. You could also try using a "cage mesh" and then a shrinkwrap modifier to the pbj sequence that switches the mesh every frame, but this will probably give glitchy results. $\endgroup$
    – TeeTrinker
    Apr 18, 2022 at 23:07
  • $\begingroup$ You could also hire a professional rotoscoper for a day :) Those people exist and are pretty good at their jobs. $\endgroup$
    – TeeTrinker
    Apr 18, 2022 at 23:12

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