I don't understand what the volume socket of the shader output (in Cycles) does. Just for experimentation, I tried plugging an emit shader into the volume and a glass shader into the surface to create a light coming out of a glass ball, but all I got was the glass. What is the use of the Volume socket and when should you use it?

  • 1
    $\begingroup$ possible duplicate of Smoke in Cycles? $\endgroup$
    – Aldrik
    Jun 23, 2013 at 6:51
  • $\begingroup$ @Aldrik I didn't realize that it was related to smoke. I thought it meant something different. $\endgroup$
    – CharlesL
    Jun 23, 2013 at 11:19
  • $\begingroup$ This could be merged with the other.. lets see what happens. $\endgroup$
    – iKlsR
    Jun 23, 2013 at 13:52
  • $\begingroup$ You probably want to fake Absorption? blenderdiplom.com/en/tutorials/all-tutorials/… $\endgroup$
    – Samoth
    Jan 15, 2016 at 16:48

1 Answer 1



This feature has now been added, the official documentation can be seen here.

So now you can do just what you suggest in your question:

enter image description here

Have a look at this post: Rendering smoke in Cycles?

The volume rendering socket in cycles is not currently implemented, but it's planned for 2.69-2.70

Presumably, it will be used for rendering volumetric materials. (clouds, smoke, fog, etc. it may also mean the spot lamp will be able to use "halo" like BI)

Also see what the wiki has to say:

The volume shader is currently under independent development.

When the surface shader does not reflect or absorb light, it enters into the volume. If no volume shader is specified, it will pass straight through to the other side of the mesh.

If it is defined, a volume shader describes the light interaction as it passes through the volume of the mesh. Light may be scattered, absorbed, or emitted at any point in the volume.

A material may have both a surface and a volume shader, or only one of either. Using both may be useful for materials such as glass, water or ice, where you want some of the light to be absorbed as it passes through the surface, combined with e.g. a glass or glossy shader at the surface.

There is a patch by Storm for Bi-directional path tracing and Volumes in cycles. If you don't want to compile blender yourself, there are a few builds on Graphical. (see here and here for some tests)

Also see the Gsoc project to add cycles volume texturing with openVDB, and this.

  • $\begingroup$ Ah, OK. Is that all it's for, or are there other uses also? $\endgroup$
    – CharlesL
    Jun 22, 2013 at 22:55
  • 1
    $\begingroup$ @CharlesL as far as I know, it currently does absolutely nothing (not sure why it's even visible?) and as there isn't any documentation yet, It's hard to know for sure what magical things it might do when it's finally implemented :) $\endgroup$
    – gandalf3
    Jun 22, 2013 at 23:18

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .