CPU + GPU rendering

[wal3d]

Hi.

Just for clarifying it to me. If I activate GPU Acceleration in the render menu (cinema 4d) and use the CPU, I'm just rendering with my CPUs.

But if I'm using the Graphic-Cards GPU, I'm rendering with the Graphic-Cards GPU + the CPUs?

Am I right?

Thanks for bringing me up-to-date in advance!

cheers
Wolfgang

[Zom-B]

Hey Wolle,

If I activate GPU Acceleration in the render menu (cinema 4d) and use the CPU, I'm just rendering with my CPUs.

Huh?! activating GPU does run in GPU mode (thats GPU + CPU)

A quick explanation:

Indigo is capable of Hybrid GPU + CPU rendering. So the GPU does one part of the rendering process and the CPU another!
The benefit here is that the GPU don't do material calculation stuff and don't need to load all the textures in the (limited) GPU-RAM.
The problem in this way of letting the GPU help you render is that if CPU and GPU aren't "eqivalent" in power one of them needs to wait for the other to be ready with calculation to bring "that stuff calculated together".

You sacrifice possible performance over a broader usability because of less RAM cost for the GPU and keep all the features of the main program, since Material calculation is done on the CPU (and is kind of complex to be done on GPU!)

Atm GPU rendering is only capable of pure PathTracing (no MLT and BiDir). The best SpeedUps are in open areas outdoors lit by sky or HDRI and Studio setups with big emitters and no walls outside beside the curved plane your Hero Object stands on

[wal3d]

Hi Zom-B,

thank you very much for your explanation!
Now I understand it a lot better.

But one more question, what exactly is going on if I activate GPU Acceleration:

- and choose CPU? Is this the hybrid function?

- and choose Graphiccard? Or is this the hybrid function?

What will be the best possible condition of these two?

Thanks again.
Wolfgang

[Zom-B]

Now I got your point

The CPU is a OpenCL device too and so it can also render in that mode.
It is possible but has no (speed) benefit, GPU stays unused...
To render CPU + GPU choose your Graphics card then both do render, enjoy the ride

Do a quick test rendering your scene 3minutes on pure Path Tracing and compare to 3 minutes with GPU enabled, you should notice some speedup (but in general not super incredible on).

[wal3d]

Hi Zom-B,

aaaah ... yes, that's what I want to know ... now everything (not exactly everything of Indigo) is clear!

Thank you very much for your great explanations ... now I feel more comfortable in Indigo.

Wolfgang

[Tramis]

Hi all, I'm new here

Sorry for bringing this old thread back, but I have one question regarding GPU. Atm I have AMD Firepro V4900 graphics card. It's not meant for rendering.
I'm a beginner 3D artist, should I chose Gaming or Workstation card for rendering? It doesn't matter Nvidia or AMD for me.

Any suggestions?

Cheers,
Tramis