PDA

View Full Version : Ice Shader ( looking for)



operation
12-04-2005, 05:08 AM
hi guys,

I have Vue d'Esprit but it's very slow.

And I have to do for a client a sequence aka "Last day after tomorow ..." (opening sequence)...

Iceberg (maybe some SSS effect). Do you have some advice ?
I need to make solid iceberg ( huge block) and small ones ( SSS).

I sculted my icebergs in Vue, I want to render under LW.
But don't know if I will use G2 or SKA ... or Chanlum ...

help ! :)


Thanks.

Silkrooster
12-04-2005, 03:20 PM
I beleive there is a thread on spinquad about modeling ice.
Silk

Iaian7
01-04-2006, 11:12 PM
It's funny, I was getting ready to post a few WIP images when I came across your question. First off, I'd suggest a little bit of research (hoorah for Google images!)... I kinda did my stuff freeform and they're not at all realistic.
As for SSS use, ChanLum was practically made for projects like iceburgs... very fast, great effect, and free. These images, are just a starting point... not exactly what I'd call my best texturing work, but here's a quick walkthrough of the different settings:

Colour: white, but with a couple of procedurals to give depth and texture.
Luminosity: sixty percent... this is where you adjust the strength of the ChanLum effect, 0% gives no effects, 100% could be used for complete illumination instead of diffuse (I'll have to use this sometime... finally, better diffuse scattering!)
Diffuse: 80%. I was back lighting, so I wanted to blow out the edge a little. The diffuse and luminosity will, of course, layer a little bit, so be careful with setting both of the high.
Specularity, Glossiness, and Reflection were set to 60%, 60%, and 20%. The numbers are really just arbitrary, since different lighting will often need different settings. Plus the reflection would need to be set to 0% for snowy icebergs, as opposed to icy icebergs.
Transparency, Refraction, and Translucency weren't even used.
Bump was set with a couple turbulence shaders, and then the bump displacement enabled in Layout.

Fast Fresnel was used for the obligatory edge reflections (keeping in mind that LW reflections are always additive, so to prevent unnaturally bright areas, decrease the Diffuse when increasing Reflectivity).
and of course... ChanLum (Mac edition, since I'm on a G5) with 64 samples, a radius of 2', and Type set to Area. Obviously the radius will change depending on your geometry scale, and the effect you're looking for. Download it here: http://members.home.nl/mlon/lw_chanlum/
Some notes about ChanLum: it does not support Multithreading (really killing me...) nor does it support transparency and ray traced shadows, without slowing waaaaaaay down. I'm working on a few tests using transparency and shadow maps, hopefully I can get them posted shortly.

Be sure to check out Ztreem's ice, just beautiful! http://www.newtek.com/forums/showthread.php?t=34307&page=3&pp=15&highlight=chanlum
So in short, yeah... I'd recommend ChanLum. :) I appologize if this is too much detail or anything, I wasn't sure what all your question meant to entail.

Iaian7
01-04-2006, 11:39 PM
Ok, here is the link to the two ChanLum / Coffee! texture tests I ran... obviously the surface settings are different between the two, but the biggest change being the use of Coffee! in Shader 1, and LW's own thickness based gradients in Shader 2. http://www.symboleffects.com/newtek/Shaders.html

Interestingly, Coffee! rendered between 30-50% faster than the thickness gradients in the colour and transparency channels, and while it didn't produce errors when geometry overlapped (i.e. the thumby thing the sticks out goes much lighter when in front of the rest of the object), the refraction effects were... weird. I guess neither render really tickled me.
You can get Coffee! here: http://koti.mbnet.fi/anttij77/Plugins/Coffee.html

While these texture tests will never pass for ice, they incorporate two important pieces: volume based colouration, and transparency while using ChanLum. The later, as stated above, is achieved by using shadow maps, instead of ray tracing.
When looking through my glacier and iceberg reference files... the colouring is a bit more complex than just a strait SSS effect, since the colour becomes exponentially more intense as the ice gets thicker. While this would be an incredible addition to ChanLum, it doesn't support falloff curves either, which would also help (not that I'm complaining, I'm just relieved to have a great, simple SSS plugin for the Mac!!!). Depending on your desired image, and the modeling setup, you may be able to use thickness based gradients, or Coffee! to do this. I haven't tried much with it yet, so can't really say.

Anyway, I hope this helps. Keep us all up to date, I'd love to see what you come up with!
:thumbsup: