1
$\begingroup$

I have a night city animation. This consists of multiple mesh cubes with window image textures. The windows are lit by using an emission in the Principled BSDF.

When rendering in Eevee, is it possible to render only the light in the scene and make all black transparent?

enter image description here

Improve this question
$\endgroup$
6
  • 2
    $\begingroup$ Did you try enabling the Emission render pass ? It won't give you transparency (as expected for emission passes). $\endgroup$
    – Lutzi
    Commented Mar 7 at 8:27
  • 2
    $\begingroup$ As @Lutzi says, you can use the Emission pass in the View Layer Properties under Passes > Light > Other. Not all light passes work in EEVEE, but this one does. And even though it has no transparency, you could still add that emission to a non-transparent background and the black parts will not change anything. For transparency you could also use the Emission pass and plug it into the Alpha input of a Set Alpha node, of course non-white emission will be semi-transparent, but by increasing contrast or maybe just using one color channel by separating them this can be changed. $\endgroup$
    – Gordon Brinkmann
    Commented Mar 7 at 9:29
  • 1
    $\begingroup$ But this could have been a good situation where to use the Cryptomatte node. In the Passes you can enable Cryptomatte passes for Object, Material and Asset. This would only work if those lights were materials on their own, and not just masked parts of a mostly non-emissive material. But yours should work. Therefore I will just link to an answer where I explain the use only in case you are interested: How can I exclude a material from the Alpha channel? $\endgroup$
    – Gordon Brinkmann
    Commented Mar 7 at 9:34
  • $\begingroup$ Lutzi, Gordon - Many thanks! Using the Emission pass & Set Alpha node does exactly what I'm looking for. The semi-transparent parts give a nice effect. I can use this as a separate overlay when I'm putting this together in the Video Editor - gives me more control over the Brightness and colour tone - Many thanks again! $\endgroup$
    – Luponian
    Commented Mar 7 at 12:27
  • $\begingroup$ Dumb question - how do you mark a question as answered, it's probably staring me straight in the face, but I can't see a 'Tick Complete' box anywhere. $\endgroup$
    – Luponian
    Commented Mar 7 at 12:39

0

Reset to default

You must log in to answer this question.

Browse other questions tagged .