To start, I am familiar with What is branched path tracing and how is it useful?

That answer is great, but I am wondering with all the pros of Branched Path Tracing, like...

  • Splitting rays
  • Advanced control over sampling
  • Reducing fireflies
  • Overall greater realism

...it seems that there are no cons, yet Path Tracing is still the default. I guess what I'm asking is why shouldn't I use Branched Path Tracing?

  • 2
    $\begingroup$ rendering with BPT on CPU is very very slow and the result is not always better than the default tracer, even with the full control you have on samples. I guess the speed is unnoticeable for those who render on gpu since you didn't mention this in your cons list. $\endgroup$
    – user2816
    Jul 2, 2016 at 15:06
  • 1
    $\begingroup$ @root I would be on a GPU. $\endgroup$
    – Shady Puck
    Jul 2, 2016 at 15:07
  • 2
    $\begingroup$ In my experience it just doesn't always help, especially on CPU. But in certain scenes it can dramatically reduce my rendertimes. $\endgroup$
    – PGmath
    Jul 2, 2016 at 15:13
  • $\begingroup$ @ShadyPuck Sorry, hit enter instead of backspace. $\endgroup$
    – PGmath
    Jul 2, 2016 at 15:14
  • $\begingroup$ @PGmath Ok. I will be posting a follow-up question with the scene that I'm working with. $\endgroup$
    – Shady Puck
    Jul 2, 2016 at 15:16

1 Answer 1


I've tested tens of scenes using BPT and regular PT and so far there are no major cons at all when using BPT. Some somewhat minor issues would be, knowing how to tweak the settings manually and slower viewport refresh during the first few samples (samples in BPT are slower)...

Other than that the its easier to test your models using regular PT and at the end of your scene switch to BPT when you know all the details of the shaders you are using...

As far as CPU vs GPU it seems to work the same, meaning it always beats regular PT, at least in all my tests, probably older (2015-2016) versions of Blender had no advantage using CPU, but as far as newer versions (2.78 and up) it is the better.


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