Author Topic: Need help for Volumetrics  (Read 3664 times)

2017-06-16, 14:00:13

Aenard

  • Active Users
  • **
  • Posts: 11
    • View Profile
Hi,

I've been trying to make volumetrics on Corona for almost a year, first in max, i gave up, now in c4D, and i'm "about" to give up.
Just did everything as in this tutorial :
(Corona Sun + sky, volumetric mat on box with camera outside etc). I tried to change all settings numerous time, and the only result i get are
- a darker, weird scene
- totally black scene
- Normal render.

Feels like the old voodoo magic of vray and drives me totally, totally crazy ; especially when i know that it's probably the elephant in the middle of the room i cannot see -_-
Can't upload the file cause it's an ongoing company project, but i'm open to any suggestion.

Thanks in advance !

Thanks in advance.

2017-06-16, 15:51:27
Reply #1

Cinemike

  • Active Users
  • **
  • Posts: 782
    • View Profile
Try the following:
Set Absorption color to a light gray (not white), directionality in Scattering to something between 0.5 and 0.9 and go on from there,

Hope this helps,
Michael

2017-06-16, 16:18:51
Reply #2

maru

  • Corona Team
  • Active Users
  • ****
  • Posts: 10897
  • Marcin
    • View Profile
Here are some tips to get pronounced godrays:

1. Sun should be low above the horizon
2. Sun should shine directly into the camera
3. Contrast between sun and sky should be high (e.g. lower sky intensity, leave sun intensity at 1)
4. The fog material should have high directionality
5. Enabling "single bounce only" for the fog material will get rid of light bouncing around

6. And now the most tricky part...
There is "enviro distance" parameter in Development/Experimental stuff rollout in 3ds Max (and C4D it's in the same place). The godrays will work best if you lower fog absorption to some very low value (in my test 20m), and enviro distance to even lower value (otherwise you will end up with black render - in my case I used a crazy value of 1m for enviro distance).

I tried creating a similar scene, and my results + scene are attached. I did this in 3ds Max, but I am sure it would work the same in C4D, unless there is some bug there. But I remember testing some fog stuff in C4D, and all worked fine.

Feel free to use my scene as a reference, or just copy and paste all the values into yours.

2017-06-16, 17:14:24
Reply #3

Aenard

  • Active Users
  • **
  • Posts: 11
    • View Profile
Hey, thanks for the inputs.

Sadly, none of it is working and i can't open the max scene here to check the settings. I had some bloom at some point though :)
Anyway, time to end the week soon and renders to start before that, but i join a cleaned version of the scene so anybody can give it a shot and tell me where the damn elephant is hidding.

Thank you very much and good weekend !

2017-06-16, 18:41:31
Reply #4

TomG

  • Corona Team
  • Active Users
  • ****
  • Posts: 3944
    • View Profile
The camera (or at least its clipping plane) is inside the volumetric object, so volumetrics won't render - move the volumetric object further from the camera.

The Absorption Distance is also too high for the scene, and the color of Absorption and Scattering too dark (very slight changes in either of these colors will make a big difference!) Attaching a modified version of the scene where volumetrics are visible and settings can hopefully be tweaked from there to get the result you are looking for!

2017-06-19, 11:33:51
Reply #5

Aenard

  • Active Users
  • **
  • Posts: 11
    • View Profile
The camera (or at least its clipping plane) is inside the volumetric object, so volumetrics won't render - move the volumetric object further from the camera.

The Absorption Distance is also too high for the scene, and the color of Absorption and Scattering too dark (very slight changes in either of these colors will make a big difference!) Attaching a modified version of the scene where volumetrics are visible and settings can hopefully be tweaked from there to get the result you are looking for!

Aaaaaaaaaand, there is my elephant. The freakin clipping plane. Not the first time this bad boy drives me crazy >_<
Now i can have fun with my new toy, thank you very much !

2017-06-19, 13:40:35
Reply #6

TomG

  • Corona Team
  • Active Users
  • ****
  • Posts: 3944
    • View Profile
Most welcome! Have fun with the new toy :)