Non Directional Lighting on Clouds

[kent_m]

Hello folks,

Is there there a way to simulate "ambient Occlusion" or "non directional" (or ALL directional) lighting in Terragen? Basically Ambient Only lighting, no sun. I want the scatter but not the source.

I'm searching through the program now to find a way to simulate that but its been a while since I've used Terragen so any tips or pointers would be very welcome.

Thanks very much,
Kent

EDIT: I've found the Ambient Occlusion Mode of the Enviro Light, I assume this is the right direction to persue?

[Matt]

Hi Kent,

I think it should be possible to do it that way, but only with the Cloud Layer V2. And even then you might find that there isn't as much detail in the shading of the clouds as you'd like.

Another approach would be to use a handful of Sunlights spread across the sky, and on each Sunlight node disable "Glow in atmosphere and clouds" - this will spread out and reduce the peak brightness around the sun so the cloud appears to be lit from a broad area of sky. If there are any hard straight-line shadows visible in the clouds you can soften them by enabling soft shadows and increasing the soft shadow diameter.

[kent_m]

The array of sunlights approach is exactly what I was experimenting with :-)  and yes I found that there wasn't as much detail as I preferred in the Ambient approach. Its almost a "density" effect that I'm after...

I'm getting what I think is close - more experimentation needed - to what I need using the array method and by adjusting the lighting parameters of the cloud layer...

A follow up question is: do you know if there is a node I can attach to a cloud layer that will allow me to alter/override the lighting parameters of that cloud layer? This would be to facilitate setting up render layers without having to duplicate the cloud layers.

Thanks very much for the reply!

EDIT: Looking into Render Layers now...

[kent_m]

A follow up to this last question. 

What I want is to be able to alter DOWNSTREAM the values of a cloud's /Lighting parameters: 

- Sun Glow Amount
- Softness
- Param C
- Enviro Light

So that I can set up ONE cloud design and output two different looks. Is this possible? 

I see inputs for the  Enviro Light but this is upstream... I'm looking into documentation for the functions now but I'm more of an art guy, any tips very much appreciated!

[Matt]

You can use the Light Groups feature of a Render Layer to use a different set of Sunlights and Enviro Light. There isn't a way to do this for the cloud parameters, but you might not need to change the sun glow amount on the clouds if you enable/disable the "Glow in atmosphere" parameter on the Sunlights.

[kent_m]

Thanks for your responses and tips, I appreciate it. 

I'm setting up the render layers now to get the different outputs for the lighting. Nice feature I'm very glad it was added.

Unfortunately in order to bring out the detail in the clouds I'm looking for in that pass it does seem necessary to adjust those other parameters. I'll keep experimenting though.

Thanks again.

[kent_m]

And a quick follow up... I think this question has been answered to the best degree and depth possible - but - a parting feature request: The ability to affect parameters of clouds, downstream, with nodes in the flow.

All the best! thanks again

[Matt]

I can see how that would be very useful in some cases. We'll think about ways we might be able to do this.

[kent_m]

Hello, I'm getting back to this and am very curious if this idea of affecting cloud settings using 'downstream' nodes was explored?