How do I add god rays with SY Depths

Taylor-S-Rose

The other week I bought SY's Depths.

https://www.daz3d.com/sy-the-depths-iray

One of the things in the description says that the god rays in the promo images "...are not postwork. They occur naturally when you shine a bright light through the water objects with the murky shader options on, as for instance if you start with Under Surface Setup 06 and then turn the caustic light up."

I'm using Under Surface setup 05 and I've applied the shader murky option to the water column. Then what I did was add lights outside of the water column shining inward, and all they did was, well, make the scene brighter. :D

I say "lights" because originally I tried a point light, and then a spot light, and neither worked. I can't seem to figure out how to make the lights show like god rays in the promos.

What is the "caustic light" that I turn up? I looked it up on Google and it lead to several unrelated rabbit holes.

crosswind

Check the attached screenshot...

NorthOf45

The setup places the water, the lights and the camera. One of the lights is the caustic light, which should create those god-rays with that wavy pattern (from the Caustic Light Plane)

The Murky water shaders set the subsurface scattering needed to get those god-rays. Check the surface settings under Volume group for the water. Others set different values to get darker or differently coloured water. Only the Murky presets will set any scattering values. Darker water will not scatter as much light, so the caustic light intensity needs to be boosted when needed. Look for the Luminous Flux setting on the Lights tab when the Caustic light is selected.

Select one of the HDR's to get a suitable Environment light. Adding more spotlights will only scatter more light through the (murky) Water, making it brighter, as you noticed. The existing Caustic light will be enough to get some effect. Note that it can take a while for the god-rays to render. It works best if the camera is inside the volume, but you can use the perspective view from outside to appreciate the scene layout.

Taylor-S-Rose

Ohhhh, I see what I did. The Caustic light doesn't load when you use the Deep Water setups, only when you use the Under Surface setups (which makes sense). Thank you!