Anybody can say me why I can't use volumetric light when there is something behind?... Example : I put a volumetric light alone in my scene, no problem, when I render the scene I can see the volumetric light, but  if I put the same light into a room for example, the light works, but NO volumetric light. It seems vomumetric light needs sun light to work, as if volumetric light was dust or smoke (see picture attached) !!! I try lot of seetings but nothing works

Thx for your help.

Did you try enabling infinite & visible settings, as well gradient,  fall off settings?
~Sazzart~

It might also be that the material of the light cone triggers by the amount of light available. It could simply be brighter in an open scene because the open scene provides additional light from the bryce sun?

 I think that the problem is that the v-light is being shadowed. If you turn off Receive Shadows then the v-light shows up but objects inside the light don't cast shadows. Try the light setup I show here and see if that works for you. Bryce image is the light inside a cube.

Thx  a lot Dan In fact I have seen when you put a light in the scene, the default setting in materiel room  is "Light Sensitive". If I change that just as you show on your piuc and select "Basic Shading" I can see the volumetric cone of light.

Thx a lot

You can see on my pic the most realistic result...for me...

Thx

sorry for the pic...

My settings