Translucent juices (KeyShot 4)

Started by DriesV, February 03, 2013, 02:56:15 PM

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tsunami

Quote from: DriesV on February 04, 2013, 03:40:29 PM
Upping the ante a bit.
I decided to go for a sort of "high-end marketing look". With all the tasty droplets and condensation to go with it. ;)
Condensation is all KeyShot work.

P.S.: I'm willing to compile a little howto on model preparation (CAD/modeling app side), material setup, lighting, textures...
If anyone's interested. ???

Dries
Love this one Dries!!!it's getting me to drink it..:-)...some postwork for water balls in the glass or ar them 3d modeled?

DriesV

Thanks!
The droplets are SolidWorks geometry (cut spheres ;)).
Only post work is glow around edges of glass and the lens flare.

Dries

zpaolo

Quote from: DriesV on February 05, 2013, 04:27:58 AM

The idea is to model your liquid as a solid and then model your glass around it (or the other way around :P) as surface geometry. Where there is liquid, there shouldn't be glass geometry.


This is the approach all rendering engine suggest, from Maxwell to Vray etc. If you model your glass like this that explains why it won't work well with "solid glass", because the surface of the glass is not "closed" so solid glass can't find the "exit surface" for the rays. Another trick that's needed for many rendering engines is separating the liquid solid in two surfaces: side surface and top surface, this is needed because top surface is an air/liquid interface, while side surface is a glass/liquid interface. But in that case you could not use translucent materials I think...

Paolo

DriesV

Quote from: zpaolo on February 05, 2013, 04:43:35 AM
Quote from: DriesV on February 05, 2013, 04:27:58 AM

The idea is to model your liquid as a solid and then model your glass around it (or the other way around :P) as surface geometry. Where there is liquid, there shouldn't be glass geometry.


...If you model your glass like this that explains why it won't work well with "solid glass", because the surface of the glass is not "closed" so solid glass can't find the "exit surface" for the rays.
...


In fact KeyShot standard "Wine glass" scene is set up like this. It has a "solid glass" for the glass, which is an open surface.
Solid glass works great for "liquid/dielectric" approach, but it is not suitable for translucent liquids. Somehow...

Dries

zpaolo

Quote from: DriesV on February 05, 2013, 05:10:18 AM

In fact KeyShot standard "Wine glass" scene is set up like this. It has a "solid glass" for the glass, which is an open surface.
Solid glass works great for "liquid/dielectric" approach, but it is not suitable for translucent liquids. Somehow...


Just making hypothesis here, maybe the passage from the "opens surface" solid glass to the liquid solid glass works well being the same kind of material, while from open solid glass to translucent has problems...

Paolo

DriesV

No, no... :D

I thinks it has something to do with the way KeyShot handles light passing through solid glass.

Check out these test images.
Glass geometry is solid and fully closed. Liquid solid 'blob' in suspension has 5mm offset from glass walls.

1st image regular glass, 2nd image solid glass.
You can clearly see the translucent blob renders way too dark behind solid glass.

Just try and render anything underneath a solid glass dome... You'll see it won't work well. ;)

Dries

zpaolo

Just to exemplify what I meant, this is the same perfume bottle model, two solids (one for the glass and one for the liquid) with touching faces. First one is Keyshot rendering, second is Lightwave. It's not a great problem to tweak the model to make it work right with Keyshot, but it would be great if it could just work :)

As for solid glass, you are right there's something different in the way Keyshot manages it...

Paolo


XD1


XD1

Quote from: DriesV on February 05, 2013, 04:27:58 AM
Quote from: zpaolo on February 05, 2013, 02:32:32 AM
I will hijack this post to talk about one issue I'd really LOVE to see solved by some rendering engine: when dealing with glass and liquid you always have to pull tricks like splitting surfaces, enlarging the liquid volume... it would be really really nice to be able to set up a liquid in a simpler way, letting the software resolve the contact between inner glass and outer liquid surfaces.
...
Paolo

Hi Paolo,

That would indeed be great!
For now, the approach as outlined in these images is working fairly well for me for translucent liquids in glass.

The idea is to model your liquid as a solid and then model your glass around it (or the other way around :P) as surface geometry. Where there is liquid, there shouldn't be glass geometry.

Dries
Does it have to be done like this? What about the other way around? Like this link tells.
https://grabcad.com/questions/tutorial-render-liquid-in-a-glass-with-keyshot

Where the juice is the sufaces and the glass a solid.

XD1

Quote from: zpaolo on February 05, 2013, 04:43:35 AM
Quote from: DriesV on February 05, 2013, 04:27:58 AM

The idea is to model your liquid as a solid and then model your glass around it (or the other way around :P) as surface geometry. Where there is liquid, there shouldn't be glass geometry.


This is the approach all rendering engine suggest, from Maxwell to Vray etc. If you model your glass like this that explains why it won't work well with "solid glass", because the surface of the glass is not "closed" so solid glass can't find the "exit surface" for the rays. Another trick that's needed for many rendering engines is separating the liquid solid in two surfaces: side surface and top surface, this is needed because top surface is an air/liquid interface, while side surface is a glass/liquid interface. But in that case you could not use translucent materials I think...

Paolo
So you got my answer I think. Doing it your way as on this tutorial.
https://grabcad.com/questions/tutorial-render-liquid-in-a-glass-with-keyshot
You can't use translucent materials ? Isn't the wine translucent?

Will Gibbons

Glad this was dug up. This is a super helpful thread. Many thanks to Dries!