Simple light preset

yagakisan
Posts: 35
Joined: Mon Jun 06, 2016 4:06 pm

Simple light preset

Postby yagakisan » Thu Aug 03, 2017 2:27 pm

Hi all,
in my last rendering with Reality on DAZ Studio I noticed a big difference in render time although the scenes I was rendering were very similar and with the same lights.
In the first scene (2 figures in a room - 1 top mesh light 200W + 1 mesh light 200W - 1024x768) after only 125 samples and 20 minutes of rendering, the image was already acceptable, just a little noisy but I could use it with a minimal postwork.
The second scene, same setup, after 20 minutes and more samples the image was still too noisy and even with postwork was unusable.
Since I'm use doing animations, the render time is real important to me.
Now, I don't want to dig too deep to understand what was different between the first and second scene, but I can't understand why I'm never able to obtain a correct BRIGHTY light for my scenes... If I've been able to obtain this wonderful result of 20min, there must be the possibility to do even better!

So I ask you experts: is there any ready-to-go light preset for having this result?
What I need is a simple, brighty room.

Of course I read some light tutorials, like the basic one on preta3d about the sunlight in the crypt, but honestly I can't understand where I'm doing wrong.
I tried scenes full of lights of any type, but the render is always noisy.
Can anyone explain how to setup this environment?

Thank you
Last edited by yagakisan on Sat Aug 05, 2017 3:44 am, edited 1 time in total.

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sigstan
Posts: 360
Joined: Sat Jan 24, 2015 3:59 pm
Location: Denmark

Re: Simple light preset

Postby sigstan » Sat Aug 05, 2017 3:29 am

There is no silver bullet for this, but here is a couple of pointers for speeding up renders:

  • Keep resolution as low as you can accept artistically
  • Avoid too many lights as each light usually adds to the render time.
  • Avoid turning geometry into light, especially if the geometry in question has multiple surfaces. Each surface becomes a light.
  • Keep the number of light groups at a minimum. You can "bake" all lights into one light group, once you have found the right settings.
  • If acceptable only use an IBL for lighting, since this can provide the fastest renders possible (minutes sometimes).
  • Never render in a completely closed room, if you do not want long render time. Always remove at least one wall and if possible the roof. This will reduce the time taken for a ray to be calculated, since it will reduce the number of bounces. Once the ray leaves the room it will be considered complete, and a new can be traced. Note that light bouncing around increases realism significantly, but it does take time.
  • Avoid overly bright and glossy materials as they can cause noise issues.You can use these materials, but just lower brightness and glossiness.
  • Avoid materials using glass, mirror and caustics.
  • If your characters are not really in closeup-shots or in bright back light, consider turning off SSS for their skin materials. This can speed up renders considerably.
  • Reduce FFs removal to 0 in scene configuration.
  • When doing animation, use Mono-directional with Sobol for speed.
A lot of the suggestions above can decrease realism in your scene, but that is the price you pay for faster render time.

Hope this helps.
Last edited by sigstan on Sat Aug 05, 2017 5:50 am, edited 2 times in total.
/Sigstan

yagakisan
Posts: 35
Joined: Mon Jun 06, 2016 4:06 pm

Re: Simple light preset

Postby yagakisan » Sat Aug 05, 2017 3:52 am

Thank you very much sigstan, I'll treasure your tips.
BTW yesterday I tried different setups to find out what was the best light and in the end I realized that decreasing the dimension of the mesh lights, the render was definitely faster.
I also added the IBL light, and the result was acceptable.
I was already working with the objects included in the visual only, and I changed to Matte all the materials less important to me.

Anyway I'll try with your suggestions, thanks again!

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sigstan
Posts: 360
Joined: Sat Jan 24, 2015 3:59 pm
Location: Denmark

Re: Simple light preset

Postby sigstan » Sat Aug 05, 2017 6:07 am

yagakisan wrote:BTW yesterday I tried different setups to find out what was the best light and in the end I realized that decreasing the dimension of the mesh lights, the render was definitely faster.

The larger you make mesh lights, the more diffuse the light becomes. Large mesh lights are basically soft lights and depending on the scene this might result in increased render time. basically you should use IBL for global illumination and mesh lights for more specific lighting.
/Sigstan


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