3d volumetric ice cracks

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  12 December 2012
3d volumetric ice cracks

I'm trying to come up with an ice shader that has all the cracks, bubbles and fuzzies like this picture shows.



I spent the afternoon trying different options with Maya Fluids, parti_volume, and the 3d shaders. So far the Maya Fluids seems the most promising if I enclose it within an mia material. The stumbling block right now is getting sharp enough strands like the picture below shows.



Come to think of it... maybe Paint Effects to generate some of the fracture lines could work...

If someone could point me in the right direction I'd really appreciate it.
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www.mattpaquin.com
 
  12 December 2012
Here's the result so far. I ended up just using some Paint Effects geometry inside a sphere. The mia materials were all pretty straightforward. I took a little artistic liberty with the BRDF and fresnel settings. Supposedly ice has an ior of 1.3 but I didn't really like the look if I left it there.

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  12 December 2012
that looks neat ... can u explain more what settings did u use to get the look? if you dont mind
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LDEA Kon Kuatica
 
  12 December 2012
Here's another one, this time using a 3d cloud shader to drive translucency of the mia with caustics on. I quite like the effect. I haven't touched 3d shaders in years so I'm having some fun with this.

@SePu started with the glass solid preset. Turned off skip reflections on the inside. I could be wrong about that one, but I'm guessing despite the ice being a solid that the edges would still be reflecting objects on the inside. Aesthetically the additional reflection just help break things up. On this last render I had the ior set back to 1.33 so I guess the experts were right on that one. The image below has it at 1.9.


Its a Solid, Refractive Caustic, Use Translucency, Color is white, and the weight is driven by the 3d shader.
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www.mattpaquin.com
 
  12 December 2012
I'd love to see a combined render with that cloud shader and the PFX geometry, too! I'll bet it would get you 95% of the way there, that PFX one already looks really good and realistic, albeit a bit more like cracked glass than water.
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  12 December 2012




Added some bubbles here as well. The only thing I didn't like in the animation was that the cracks stopped looking like cracks and started looking like frozen bits of plastic. So I went back and tweaked their shaders, no diffuse, refractive caustic and we'll see how it animates in the morning. The still took 3:55 with all the settings cranked up at 640x480. My machine is getting a little old, but with all the raytraced transparencies and caustics.... and I forgot to mention theice cube shader group has a parti_volume in its volumetric slot. That was important.

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www.mattpaquin.com
 
  12 December 2012
I think you're doing well here, cool methodology.

Look at the first sample image and then at your last post's render. The ice now looks, well, dirty... As in, the fractal shader you're using (cloud) as the translucency is too dark. I think if you ramped this up with a multiply/divide node, say at 4x or 10x the value, it would make your ice look much more realistic? Brighter and whiter and thus simulating the microfractures you see in your sample photo better, possibly?

Just an idea!
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Commodore 64 @ 1MHz
64KB RAM
1541 Floppy Drive


"Like stone we battle the wind... Beat down and strangle the rains..."
 
  12 December 2012
Looks like I'm the one who need to learn from you instead... lol. I really like the first render you did. Any chance you can share how you did it?
 
  12 December 2012
Quote: Look at the first sample image and then at your last post's render. The ice now looks, well, dirty... As in, the fractal shader you're using (cloud) as the translucency is too dark. I think if you ramped this up with a multiply/divide node, say at 4x or 10x the value, it would make your ice look much more realistic? Brighter and whiter and thus simulating the microfractures you see in your sample photo better, possibly?


Turned out the volumetric shader was making it too dark, which makes sense in that the particulates in the object would be getting darker. It also shot the render times through the roof, so getting rid of it was a big help. It was a cool look, but using translucency seems to be better. Some ice is more opaque than others, so its good to have the option.

Here's the latest update. I started using particles for the bubbles.



There's other steps at my blog.
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www.mattpaquin.com
 
  12 December 2012


Calling it done for now. Moving on to model the scene next.

I'll try and post a tutorial, hopefully sometime next week.
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www.mattpaquin.com
 
  12 December 2012
looks great. Nice work
 
  12 December 2012
Thanks cgbeige.



Found a solution for a different cloudy look. Separate geometry on the side that's driven by a 3d Maya cloud texture. I'd still be interested in doing this with just shaders on the mia material. For now I'll probably stick with what I've got.
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www.mattpaquin.com
 
  12 December 2012
ive been over on renderman university studying rms 4 and i notice they have an article about cracked glass which has a cool effects using dynamic curve creation which reminded me of your paint fx ice

its more complicated than you want to get but an interesting reference maybe

http://renderman.pixar.com/view/impacts-on-glass
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Scott Turner
 
  12 December 2012
That's awesome blade33ru. Thanks for that. It got me thinking about curves which would be pretty useful. For mental ray the best way to get curves to render is just converting them to Paint Effects geometry and then converting that to polys. I'm playing with some twist options and clipping masks to get some interesting effects.

I'm trying to make a patterned tile ice floor at the moment. At first I started in ZBrush using the radial painting options to make some cool designs. Now I'm trying to get that transferred into geometry. Polygroups from polypaint and then extracting into subtools seemed like the way to go, but for the size and detail I'm working at its kind of choking. My next try is going to be with NURBS, and obviously a different design.

Still having fun with this. I haven't touched caustics since I was warned they were too computationally expensive. So far I haven't had a problem on my aging MacBook.
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www.mattpaquin.com
 
  12 December 2012
Try decimation master with zbrush.
 
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