Bottle of Liquid with Vray

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  09 September 2012
Bottle of Liquid with Vray

I've been battling this for a while now and seems i cant get it right..

How do you render a glass of colored liquid in Vray?! (actually a parfume bottle in this case)

the liquid material?: Refraction Fog color? or Volumetric Fog in the Shading Group's Volume tab?

What render settings do you use? secondary Brute Force or Light Cache?

I KEEEEP getting black edges / spots nomatter how high my refraction depth is.. and one time i got it to look "okay" but then when i rendered my sequence I got a ton of artifact pops on multiple frames..

Lighting - im using a Studio HDR map that doesnt actually have any solid blacks in it, so the black spots shouldnt be caused from Refraction catching black scene space?

Lastly - do you make the liquid part as a separate object or just add a separate shader to the inside of the container geometry?

would LOVE some advice on this subject ... maybe even a tutorial cos learly - im missing something lol.

Seems i only have this issue when im trying to Layer refractive objects..


thanks

Adam
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Adam Oestergaard
www.adamoe.com
 
  09 September 2012
there are some good tips here:

http://www.spot3d.com/vray/help/150...ssinterface.htm

If you're rendering a liquid inside a container, there's no easy way to fake it you need to have a thin wall and then have the liquid overlap with the thin wall.

If you're getting black edges, it is probably a trace depth issue. Unless you need caustics, you don't need brute force but jacking up the brute force trace depth up to 8 or so should help you eliminate that as the source of the problem (it's very slow so that's just to test). Don't forget to change both the shader refraction depth and the global render parameter. You can get some speed back with the "affect shadows" parameter in the shader, which is a fake.

I have found that if I use light cache for scenes that contain caustics, it looks splotchy and bad, so that's why brute force is better for those.

http://www.can-con.ca/tumblrpics/iv_and_stand2_two.png

The bag was tricky because I had to extrude the inner wall and then create a liquid from an extraction from that and then offset the faces with transform components so they are inside the bag's very thin "wall":

http://www.can-con.ca/tumblrpics/liquid_vray.jpg

it's hard to see but the blood mesh just edges past the inner wall of the bag but not beyond the outer wall. V-Ray automatically creates the dielectric interface.

But, if you're seeing black, it could also be a reflection of something. The dark areas in my blood above are the IBL's black portions, not a trace depth issue.

Last edited by cgbeige : 09 September 2012 at 12:20 AM.
 
  09 September 2012
Refraction fog is pretty great. Never had long render time problems with this, or refraction issues either.

Nice tutorial Dave!
 
  09 September 2012
thanks for the reply dave, i'll def look into doing it like that.
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Adam Oestergaard
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  09 September 2012
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