I've been attempting to make a concert stage animation in blender with the inclusion of lights, 48 for the stage referred to in this question. To achieve the look of a solid beam matching that of one in the real world I'm trying to use volume. Since the scene is fairly big and the animation is pretty long I decided against using a single volume field to cover the whole scene, this also allows me to change the colors for each of the lights independently. Instead, I've parented a cylindrical volume field to each of the 48 lights, that way there's strictly only volume where it is needed.

A view of all 48 lights.(A view of all 48 lights)

Now, upon rendering this however the process either hangs, or crashes all together. My computer isn't a monster but it's fairly powerful, and it's definitely capable of rendering volume. Matter of fact I've rendered scenes previously with more lights than this one and been fine, though those were using only a single large volume field. Considering this, I also tried using a single field opposed to the various 48 parented fields, but this provided even worse results when rendering and crashed almost immediately.

Volume is noisy but this is an export with all 48 lights enabled, but only 7 volume fields enabled.(Volume is noisy but this is an export with all 48 lights enabled, but only 7 volume fields enabled.)

Though I'm uncertain, nor do I have that vast of knowledge with blender, I'm led to believe that, since it's not the amount of volume fields, the problem lies with the amount of lights used within the volume. I can't do much for investigating this given that blender can't even output a file when attempting to render, even at low settings. At this point it doesn't need to be fast. Just being able to export a frame with all the lights and volume without crashing would be a success in my book.

Any help would be very much appreciated!

Here's the blend file.

  • 1
    $\begingroup$ Try using a single volumetric domain (a big box surrounding your scene and use volume scattering in it). It seems to me that many small volumetric cones ones is not too efficient. In the real world the lights would be visible because of the smoke or suspended particles in the room. $\endgroup$ – cegaton Oct 6 '17 at 23:27
  • $\begingroup$ @cegaton This is one of the things I tried, as mentioned in the post. This worsened the issue as it only increased the amount of volume that would need to be calculated in the scene. $\endgroup$ – huntybunty Oct 6 '17 at 23:34
  • $\begingroup$ with a single domain the scene renders fine on my computer. $\endgroup$ – cegaton Oct 6 '17 at 23:38
  • $\begingroup$ A single domain seems to absorb too much light than I'd like. With a single domain is it possible to absorb the various colors of different spot lights without creating the black fog effect elsewhere in the scene and greatly increasing render time? $\endgroup$ – huntybunty Oct 7 '17 at 0:05
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    $\begingroup$ The color should be determined by the light, not by the volume scattering. Don't use volume absorption or keep it at a very low value, otherwise it will make things darker in the distance. Your file wouldn't render in my computer the way you had it. Once I got rid of the many small volumetric cones it renders fine. Moreover, you are going to need a lot of samples to keep noise down int the volumetrics, also you need more bounces for volume in the light paths settings. $\endgroup$ – cegaton Oct 7 '17 at 0:12

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