Author Topic: Corona - God Rays - Volumetric material  (Read 13522 times)

2015-03-28, 01:24:33

88qba88

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Hey,

I just wanted to share with you guys a test render I did today after playing a bit with Coronas volumetric materials and Phoenix FD OceanText.
Picture is straight from Corona, no post production applied. If you have any questions feel free to ask.

2015-03-28, 02:52:32
Reply #1

PROH

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Hi. Really nice effect you made here :)

I've tried several times to get God Rays directly in Corona VFB without post. So far I haven't been able to make anything just slightly decent. So may I ask about how you did this? How is your scene setup? I know the basics, but keep thinking I'm missing something, since it never works out as intended.

Honestly hope you'll share.

In advance thanks.

2015-03-28, 11:15:51
Reply #2

88qba88

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No problem PROH,

1st of all there is a nice article about Volumetric Materials here:

https://coronarenderer.freshdesk.com/support/solutions/articles/5000534910-how-to-use-subsurface-scattering-volumetric-absorption-and-scattering-

There are 2 different ways to make atmospheric effects in Corona. One is to apply volumetric material to geometry and another one is to use Global Volume Material in Render Setup->Scene->Scene Environment.

(my scene units=meters)
In the scene from 1st post I used 1st method and applied material to sphere (70m radius). Camera was outside the sphere, but really close to its border. (pic 1.jpg)
Material settings is in same picture.

The only light source is corona light (sphere, radius 0,5m, intensity 200000W (STRONG ONE!) ), surrounded by smaller sphere (radius 25m-material on the small sphere is some bercon noise on diffuse and opacity layer - you can check it out on pic. 2.jpg). The role of the small sphere is to create a small volumetric disorder in the background.

and thats it.

But while working on this project I noticed something strange:

When you render a very simple scene where you have, lets say, 3 light sources floating above a ground, volumetric material set as Global Volume Material and no backgound geometry you get effect like in picture X1.

Then I create a huge cylinder (no top and bottom) around my scene, and apply "invisible" material to it: refraction=1, color=pure white, refraction IOR=1, glosiness=1). The changes it made are visible on picture x2.jpg.

If there were no volumetric material the cylinder would make no change at all. When you place any geometry behind your lighesource magic happens and you get much more interesting results.

I hope I could help!
Try it and if you get something interesting let me know

2015-03-29, 12:56:38
Reply #3

Fiorentin

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Nice! I have struggled with getting realistic water/ocean displacement in corona. How did you manage to use the  fd ocean text, I thought it needed the vray displacement modifier.. Do you mind sharing your displacement setup?

Thanks!

2015-03-29, 23:29:48
Reply #4

88qba88

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Sure,

All you have to do is assign OceanTex from Phoenix FD to displacement slot in your corona material, then increase displacements max level to 1 meter (in my case). You also have to give the plane a lot polygons - I gave a plane that is 200x200m 100x100 segments and tesselated it (1 iteration). To give your ocean fine detail also try increasing max subdiv per poly in Render Setup->Performance->Displacement (I use value of 600).

I hope that could help!

2015-03-30, 06:54:20
Reply #5

Fiorentin

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I see, very helpful! Thank you!

2022-11-10, 15:21:33
Reply #6

Gionni

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2022-11-10, 16:03:11
Reply #7

TomG

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All articles are moved into the integrated Chaos site, https://support.chaos.com/hc/en-us - a search there will bring up articles relevant to the topic, e.g. https://support.chaos.com/hc/en-us/articles/4528475664145-How-to-use-Subsurface-Scattering-SSS-Materials-in-C4D
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