Can't make volumetric light rays in Atmocam for Iray

colinmac2

I still experimenting with Atmocam for Iray, but I can't get the volumetric light rays effect that I'm looking for.  I can get fog. But not the lighting I want.  And without Dome And Scene turned on, (instead of Scene Only) it's too dark to see ANYTHING!  Indeed, in my second pic, I can't even tell there's an Atmocam at all!  What am I doing wrong?

colinmac2

The readme says I can light with just HDR settings, but if I try this I get nothing but pitch-black-- HELP!

Richard Haseltine

HDR won't work if the scene is enclosed - by a room or by a modelled skydome, for example.

Marshian

Hi colinmac2- did you get the volumetric rays to work? If not Id suggest starting with a very simple scene until you get the feel for how it works. Load these items included with the product: render setting, photometric light, a large plane, and a cube. Now put that cube between the light and the AtmoCam and do a test render with AuxViewport. Or try a very simple scene like the one below. The main thing is you need a singular strong light source.

 

Oso3D

I find it enormously helpful to do scenes like that with canvasses or multiple passes, so I can do one pass for the rays, with one singular, very sharp lightsource, and then a second pass (or canvas) with more diffuse ambient light and no fog, and then composite.

 

colinmac2

I'm not sure I understood you quite.  Following Marshian's advice, I got this--

 

I don't think I'm making the window glass transparent enough, but I'm not sure how to do that.  The light source is behind the window, and I cranked it up to something like 10,000 cm.  Now I'm more confused than ever.

Syphonaptera

colinmac2 said:

I'm not sure I understood you quite.  Following Marshian's advice, I got this--

 

I don't think I'm making the window glass transparent enough, but I'm not sure how to do that.  The light source is behind the window, and I cranked it up to something like 10,000 cm.  Now I'm more confused than ever.

Dear colinmac2,

I could not  get it to work as well...... but as so many times with having problems getting the desired light effects concerning an Iray scene it always was the fact that added lightsources just were too low in value.

As for your try out scene , make sure you select the MAR Atmocam in the viewport.  Then crank up any lightsource you need to create 'godrays'with up to (AT LEAST!!)  1000000Lumen!! Maybe more. 
You should see 'atmospheric godrays ' created by any object in front of the light source you use. 
If necessary , dial up the 'intensity' of the lightsource ( 500% or even higher, you may need to uncheck the limits on !!) 

For indoor scenes, switch off all headlamps , don't forget the headlamp in your 'render settings'  windows , select 'never' . 

Cheers

 

colinmac2

Hey thanks, I'll try that!

colinmac2

Well, I got the full volumetric effect, but it refused to render more than 9%.

 

Image removed due to nudity

Fishtales

Volumetrics can take a while to render. Although they seem stuck at a low % Studio is still working.

Richard Haseltine

If it's really slow for you it may be timing out (by default a render stops after two hours) - you can adjust the maximum time (and samples) in the Progressive group of Render Settings

colinmac2

I knew about the Progressive Render timing, and I adjusted that.