Indirect Light and Render Engines

Hi there,

I heard a few times: Choose “this” render engine or “that” if you want good indirect lighting.

Well, sometimes people confusing optimization techniques with capabilities.
I did some tests to prove the point.
In general: the chosen render engine will not change the results significantly regarding the indirect lights from an artistic point of view.  (That was a bit complicated sentence I know. 🙂 )
It will not be totally identical as well, but all other factors (your actual lighting setup, your shaders, your textures, the used atmospheric effects, compositing etc.) will be much much more important.

Test 1:

  • An interior scene (a room)
  • One directional light
  • A simple white material with the same settings (not identical algorithms of course, but again it’s not that important)
  • Rendered with 5 bounces or identical settings (diffuse and reflection/specular as well). I used brute force methods of course.
  • Four different render engines (Iray, Arnold, Redshift, V-Ray).

That’s it.

The results:

compare_arnold_vs

In two cases I had to modify the image by +1 exposure because of the output range or how the directional light intensity is handled by that particular renderer.
As you can see the results are pretty close.
Can you tell which one is which?

Test 2:

  • An interior scene (a room)
  • One directional light
  • A simple white material with the same settings (not identical algorithms of course, but again, it’s not that important)
  • Rendered first with 1 than 2, 3, 4 and finally with 5 bounces or identical settings (diffuse and reflection/specular as well)
  • I used Iray and Arnold for this test.

The result is consistent:

compare_iray_vs_arnold.jpg

That’s it.

About render speed

I found the render speed was the following in this particular case:

  1. Arnold GPU*
  2. Iray (CPU + GPU)
  3. Redshift (GPU)
    A huge time gap here 🙂
  4. V-Ray (CPU)
    A time gap here 🙂
  5. Arnold (CPU)

*Arnold GPU is still in beta and lacking features, but it was really fast.

Final thoughts

I think for beginners the render speed is not as important as other factors.
For example:

  • If you want to create a strong portfolio speed is not that relevant (usually a few really good looking and interesting still image or a really short sequence – at least for environment artists, lighting artists, or character artists, you can add product visualization and architectural visualization to that list).
  • If your target company is using a different render engine, learn that (for obvious reasons).
  • There are a few other technical reasons why you have to choose a certain engine (a few example: inhomogeneous volumes, better SSS calculations, better particle support, physically plausible caustics, large material library etc. but the calculation of the indirect light is not one of them).
  • Speed in general
  • etc.

Optimization is a huge factor in production, but if you working on your portfolio don’t choose between render engines based on false data or largely subjective opinions.
You matter more, that the tool you using.

Cheers, D

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