Volumetrics in Cycles

Ok guys so I’ve been doing some test renders with the volumetrics in cycles with the help of Andrew Prices tutorial and i am just not feeling it like something doesn’t feel right with it :no:

I need help learning about the volumetric lighting in cycles and i have some problems that i don’t want:
i can’t have just the light rays only like theres still some fog inside of the train.
How can i render with volumetrics and still keep my world background? every time i render, the sky seems to go black. This eliminates that daylight sun feel that i want; like its a sunny morning or something and you can see the light from the sun come in.
And also, the light rays don’t seem like light rays to me for some reason i guess they look like just streams of fog idk lol

Thx for your help and critique!

For your sunny day problem, I would get rid of the volume assigned to the world and create a cube mesh with a volumetric material that only covers the inside of the train (in front of the camera).

As for removing any fog, the reason you have light rays inside of an enclosure (in real life) is due to dust in the air, you might want to control the density with a procedural texture designed to mimic a dust effect (which you would use tight gradients and a voronoi texture to achieve).

ohh yeeaa thats brilliant! but for the cube mesh only inside the train wouldn’t giving it a volumetric shader just make the whole cube a big box of fog including the inside?

The entire volume of the cube would be filled with the volumetric medium, you would also leave the surface output blank which would automatically make the surface transparent.

ahhh i see ahmo try it especially that procedural texture

i might jus make a WIP so others can follow my “journey” into volumetrics for cycles lol

heres the render without compositing btw

How many volume bounces do you have? 0?

yea i tried that honestly followed exactly by andrew prices tutorial and it didn’t work…well it did but not fully and i still kinda don’t know what volume bounces for

Eh… well I ask because I have some advice that depends on the answer… you’re not going to learn what volume bounces are for by deflecting a question that’ll result in an explanation.

oh well then whats the advice cause i can easily google volume bounces and find out thats no problem lol :slight_smile:

A lot of people must have been smoking on this train…=) The volumetrics are a bit strong for me, but otherwise good. My only complaint is that there doesn’t actually seem to be a sunny day, or anything for that matter, outside. All I’m seeing is the reflection of the train’s interior where I should be getting a bright backdrop.

thats what I’m saying owldude i can’t get that bright backdrop for some reason and its kind of frustrating i even tried to fix it in the compositor with the environment pass but that didn’t work

and thats the one thing I’m really asking for help on lol

If you have 0 bounces, then that’s why the beams of light are so strong and the rest feels like there’s no volume at all. The light needs to bounce around inside the volume in order for it to appear like it’s filled with smoke/dust, otherwise it’s just fake beams of light. If not, then thanks for wasting my time by not answering a simple question.

Also, to get the windows brighter, don’t use a world volume, but rather a cube that contains the train cart. See: http://blender.stackexchange.com/questions/13802/using-volumetrics-in-2-71-i-have-to-have-the-light-strength-super-high

i did answer the question lol but that makes since i just put it at 0 because according to Andrew Prices tutorial it removes some of the fog you get in the interior of a scene. Thx for your help though :slight_smile:

That was the worst suggestion that Andrew could have given, IMHO.


ik lol now i know to NOT do that