I attached to this post a blender scene that is a simple example of volume rendering:
First of all, I suggest you to build a simple scene (as the one attached to this post) where you can do tests and learn how the volume rendering parameters work.
Once you have built your scene (don't forget to use portals), you can start to work on the volume rendering part. You have to add a cube surrounding all the scene, this will define the volume where the volume rendering will happen:
Assign a material to this cube (i.e. "mat_volume") and define the material in Luxblend as follow:Absorption
: this parameter defines how "foggy" the scene is. Increase the values if you want to reduce how far you can see and vice versa;Scattering
: this parameter define how much the light is scattered around. If you want a more dramatic "blade of light" effect, increase the values (or vice versa);
Enable volume rendering by selecting "simple" integrator in the Render tab:Stepsize
: This value will have a huge impact on the rendering time. It defines the length of the ray marching steps. It can be used to tune how precise will be the result of the volume rendering (i.e. + or - noise). Cut in half the value and the result will be about 2 times more accurate but it will double the rendering times too. If you are going to use a lot of samples per pixel (i.e 1000 or more) in the final rendering, I suggest to use large steps in order to speedup the rendering (i.e 1.0 or more).
And you are ready for the rendering:
P.S. if you use volume rendering, be ready for looooong rendering time