Achieving that geometry/shading of a bubble bath

[Art48]

Hi,

I'm currently struggling to achieve a certain look of a bubble bath.
If you look at this reference image, I don't really have a starting point on how to achieve that modeling and shading of the bubbles, or rather what features of VRay I can use here or what way I would go to get that result.

Do I model the main geometry by hand, displace it (with what map?), or use MultiScatter to distribute little bubbles? PFlow for the bubbles? How do I get this whitish SSS look with very refractive and sharply reflective materials? Does anyone have some starting points for me? Or does anyone know a good tutorial for this kind of work? I also would have Houdini available if that helps. I try to keep it simple since it is an important but relatively small element in the scene.

[vlado]

People have done this with PhoenixFD, but it might be a bit of an overkill

http://vimeo.com/89962290
https://www.youtube.com/watch?v=UUtDPWDQPvU

Best regards,
Vlado

[Art48]

Okay, I see. I feared something like that. It's not possible for us at the moment to buy a new plugin for this :-/. I'm currently experimenting with a base geometry and scattered bubbles on top of it, all with SSS but its killing my rendertimes...

[super gnu]

i know we all want vray to do everything, but it would be good if vray had all of the shading/rendering techniques that phoenix uses.

to be honest im not sure wether it does or not, but i doubt that phoenix is doing sss on its bubbles, but it still looks good! that shader should be in vray too, imho

we now have the volume grid thing, which is a good start

[Art48]

Yeah...would be nice, but I'm not really bothered by it since the chaosgroup guys are the only software developer I know that produce service pack changelogs where I "WOW!" after every line. ^^

[vlado]

i know we all want vray to do everything, but it would be good if vray had all of the shading/rendering techniques that phoenix uses.

It already has some of those for the 3.20 service pack:
http://docs.chaosgroup.com/display/V...RayVolumeGrid#

Unfortunately the particle/foam shader is not in there right now.

Best regards,
Vlado

[Art48]

If I get a freelancer to do the bubbles in PhoenxFD would there be any way to get them renderable without a PhoenixFD licence?

[vlado]

If I get a freelancer to do the bubbles in PhoenxFD would there be any way to get them renderable without a PhoenixFD licence?

It should be possible. The demo version of Phoenix FD has no limitations with respect to rendering (only for simulating).

Best regards,
Vlado

[Art48]

Okay, that may be an option then.
Anyways - how does the foam in PhoenixFD get so nice white? It has to be SSS, doesn't it? Otherwise the light would be totally absorbed and it would get darker.

[vlado]

Anyways - how does the foam in PhoenixFD get so nice white?

The foam uses a special shader that is specifically designed to produce that effect.

Best regards,
Vlado

[Art48]

Alright. I see what I can do about it - many thanks for the information you all provided!

[Art48]

For everyone interested: I am on the right track with a base geometry of the rough form of the bubble distribution which I assigned a VRayScatterVolumeMtl and tweaked the settings so the overall reaction to light mimics the foam. Then I distribute the bubbles over that surface with MultiScatter, the bubbles having a BlendMtl of another ScatterVolumeMtl with a Glass material. The bubble geometry is a shelled sphere.

So far it seems to work although it takes a while to render...

[vlado]

I'd be interested to see the result

Best regards,
Vlado

[Art48]

I will post it when the render is done - still tweaking it

[Art48]

Well...this is the result of an 800px rendering after 12,5 hours on two machines with 3.4Ghz.
I am severely disappointed in the rendertimes.

I will now try to get the time down by limiting refraction depth even more with a ligh grey exit color.
Anything else I might wanna do?



EDIT:
For comparison - this is without the bubbles, it took 5 minutes to render.


Now I wil propably make a second rendering with a glass-like surface ontop and a heavy bump so I can get the sparkling effect - except anyone else knows a solution to get that nice sparkling