Integrating 3D models with photography
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# 1 30-09-2015 , 03:25 PM
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Join Date: Jun 2015
Posts: 8

Arnold and nested dielectric transmittance scale / transmission attenuation


Im rendering a glass with fluid, ice, carbonation and solid garnish using Arnold as a render engine.

Im having trouble with and nested dielectric transmittance scale / transmission attenuation to make the fluid darker at thicker areas.

The problem stems from how the modelling was done, ie fluid mesh a bit larger than glass as recommended, to have refraction work.

But as the rays travel like described below, the transmission attenuation only measures the ray until the next interface: coming from air, interface to glass, interface to fluid, interface to glass back side, interface to glass, interface to fluid back side, interface to glass back side.

So the attenuation only darkens the distance between the geometry overlap from fluid to glass exit, a very short distance.

Using the jf nested dielectric shader however removes the problem with a sort of rendertime booleans.

But with jf nested dielectric shader, I don't have a diffuse channel or sss, needed for smoothies and similar cream style fluids.

The jf nested dielectric shader has a feature called Other > Emission > Emit at with three options, here I understand that i can overide with another shaders color out. But the emit at interfaces makes the setup hard to configure and I could not solve it using this technique (maybe I set it up wrongfully, any one got this to work correctly?)

So for thicker fluids, I added a piece of geometry inside the transparent fluid, with a alSurface shader assigned.

This brings the best of two worlds, nested dielectrics and regular shaders.

But it reintroduces the short raydepth of the transmittance scale / transmission attenuation again.

Anyone know how to solve this senario with jf nested dielectric shader as a main shader?

Can I possibly ignore rays for the inner geometry for wanted transmittance scale / transmission attenuation, and still have the geometry visible inside the refractions?

Btw, Im pretty new to maya so I dont know all features yet.

How would you solve this? // Best Ola

# 2 30-09-2015 , 03:40 PM
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Join Date: Jun 2015
Posts: 8
Basically what I need is transparent and thick fluids with Arnold and jf nested dielectrics shader. These need to blend together with a ramp node. It has to render pretty fast so alLayer i reckon is to slow (or can you optimize it drastically with transparent materials?). If a better solution exists that has nothing to do with my above question, I'd love to hear that answer instead. Thanks in advance // Best Ola

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