portal light with volumetric effect?

[wannabeArtist]

Hi,

Is it possible to have a portal light with volumetric effect, or is there some other way to achieve the same effect?

I have tried a number of ways to get this done, including fast volume effect node and the volumic property, but so far no luck.

My current setup has a physical sky and sun for outside lighting and a simple inside-out cube for a house. Everything else looks nice enough, but I would love to see that volumetric effect on the windows

[ace63]

As far as I know portal lights do not work with volumetrics - simply get another light with 0 intensity and volumic effects and place it behind the portal

[wannabeArtist]

Thanks, better try it that way...

I almost assumed that myself - after searching half way the internet for an example and not finding anything

[wannabeArtist]

Hmm....

I'm still not getting this right...

I tried placing another spot light behind the portal light (that's outside). But that resulted in a beam of light hitting the "window" and not affecting the indoor light at all. Then I tried setting up a light box with Fast_light_effects as it's shader and oriented it to align with the physical sun.

Now I get this result: It's closer to the wanted effect, but I can see the base of the light cone on the floor... how do I make it match the portal light's (or the windows) size? If I crank it up to a really wide cone, it fills the whole room, practically removing the volume effect.

[Rork]

What about two passes and comping it. Easiest way to do it I guess.

rob

[wannabeArtist]

Thanks, Rob

However I don't really see how that would fix the mismatching of the shape of the lights.

I tweaked this a little, but it seems the basic problem stays the same. The spot light with the volumic property is not doing a very good job in matching the sun light that comes in the window no matter where I move it.

[wannabeArtist]

A small update,

I finally learned to switch on the "force volumic shadows" and now my volume light is no longer coming through walls

I still don't know how to combine this with the portal - if the portal is in place, there wont be any effect as it block the rays. Swithing off secondary rays or playing with the portal transparency settings don't seem to affect this.

I'm not much of a renderer - I've better learn to do this in multiple passes as advised. Although, I'm not sure how much I will actually gain from using the portal light for this - here's a test render without the portal light: