Stuck following tutorial on volumetric caustics

[aidalgol]

I am trying to follow a tutorial on rendering with volumetric caustics using Lux, and I am stuck on a point where the UI in the latest versions (of Blender and BlendLuxCore) do not match that shown in the tutorial. In https://youtu.be/PrHWwH_VXlk?t=356 at 5:56, it shows how to add world volumes, but my UI instead looks like this:

and I cannot set multiple volumes, only a default volume.

The tutorial states they're using Blender 2.78c, but doesn't specify a version of "LuxRender" (I notice it shows up as "LuxCore" in Blender on my system), and I am using Blender 2.79b with BlendLuxCore 2.1 (with OpenCL). How do I do what the tutorial is showing in this version?

[Fox]

node editor
water drop icon
new node tree
rename node tree
add
volume
add
output
Connect output orange dot to volume orange dot.
Camera volume set by selecting Camera and deactivating auto-detect camera volume.
When the object is selected, object volumes set in node editor material icon (left from water drop icon), add material, then connect volumes.

[B.Y.O.B.]

If you just want a spotlight + fog in a black environment, you can use a much simpler setup than in the tutorial (you don't need the "fog box").
Set a homogeneous volume as world volume (this will be used as interior/exterior volume on all unconnected volume sockets).
For the glass, use a clear interior volume.
I have attached an example scene (note: it was saved with the latest development build, so you will need v2.2beta2 or higher before you open it).
You can get v2.2beta2 here: viewtopic.php?f=9&t=1172

[aidalgol]

If you just want a spotlight + fog in a black environment, you can use a much simpler setup than in the tutorial (you don't need the "fog box").
Set a homogeneous volume as world volume (this will be used as interior/exterior volume on all unconnected volume sockets).
For the glass, use a clear interior volume.
I have attached an example scene (note: it was saved with the latest development build, so you will need v2.2beta2 or higher before you open it).
You can get v2.2beta2 here: viewtopic.php?f=9&t=1172

That's much simpler, thanks! Now any idea why I'm getting noise in my render of your scene?

I tried doubling the number of samples, but that had no visible effect. Disabling the Halt Conditions and leaving it running for half an hour gives a much better result, but it still looks dustier than your render.

[B.Y.O.B.]

Sorry, I should have mentioned that my render was denoised (with OIDN, available in v2.2beta2).
After the render is done, click on the passes dropdown in the image editor and switch it from "Combined" to "DENOISED".

[aidalgol]

Ah, I never would have found that. I kept looking in the Render panel for denoise setting. Thanks! This helps me a lot with getting going!