I need to have two smoke domains overlap each other due to the fire having different textures as well as one being affected by wind, rotating, etc. But for some reason they don't overlap right. This means that when I have the two domains overlapping each other, one domain covers the other and makes this bad effect. This is what the effect looks like:

enter image description here

Anyways to fix this? Thanks!

  • 1
    $\begingroup$ "they don't overlap right" is pretty vague. Can you elaborate, preferable with pictures? $\endgroup$ Commented Apr 12, 2017 at 0:46
  • $\begingroup$ Yeah, I included the blend file, updated the question. It's kind of like my first question with transparent alpha images in front of smoke domains. Thanks! $\endgroup$ Commented Apr 12, 2017 at 1:44
  • $\begingroup$ Just edited it. I really appreciate what you're doing! $\endgroup$ Commented Apr 12, 2017 at 1:47
  • 3
    $\begingroup$ Possible duplicate of Is it possible to have more than one smoke simulation in the same scene? $\endgroup$
    – JakeD
    Commented Apr 12, 2017 at 1:58
  • $\begingroup$ I uploaded the blend file, sorry about that! $\endgroup$ Commented Apr 12, 2017 at 2:04

1 Answer 1


The Problem

Your problem is that you are currently determining material transparency with Z Transparency. This doesn't work, since Z Transparency calculates the alpha per-face. When your domains intersect, it doesn't recalculate the alpha.

If the Domains Move or Change Size/Shape

Change the Transparency method to Raytrace:

enter image description here

This will slow down your render a little bit, since it is calculating the transparency per pixel instead of per face, but it isn't too significant and definitely produces a cleaner render:

enter image description here

If the Domains Do Not Move

If your domains are static, instead of using the Raytrace method, you can fix this by cutting an outline at the intersecting parts of your domain (easier shown than said):

enter image description here

This way, the faces of the domain inside the other domain are calculated separately from the faces outside the other domain.

  • $\begingroup$ I tried changing both domains to Raytrace but I got the same result...I think I made a mistake.. $\endgroup$ Commented Apr 12, 2017 at 20:25
  • $\begingroup$ @GodzillaDude No, I'm sorry. The mistake was mine. My solution does not actually work. I am deleting this answer now. I recommend you look at the solution commented as a possible duplicate, or try using the Cycles render engine. $\endgroup$ Commented Apr 12, 2017 at 22:39
  • $\begingroup$ Reverting this for a bit. @GodzillaDude check again if you missed something as per flag. $\endgroup$
    – iKlsR
    Commented Apr 13, 2017 at 5:49
  • $\begingroup$ Ah never mind, that was on me. I didn't check fast enough. I will, however, up this answer because it answers the question for people who work in Cycles. But if anyone knows the answer to this and works in Internal, I'm open to suggestions. iKIsR, thank you very much for going out of the way to revert that, greatly appreciated! $\endgroup$ Commented Apr 13, 2017 at 6:09

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