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Noise distortion / bulge map
Posted: Mon Jun 07, 2010 9:49 pm
by dcm
Hi all. During the week i tried to simulate some effect as in real world, mainly on glass and metallic materials. Because im dissapointed now, i hope some smart brain could help me with it.
Here is what i want to achieve :
1. metal
I tried to generate several noise maps but without sucess, maybe i was doing something wrong. I tried it in Fryrender with built-in noise generator and it was working like a charm.
2. glass
I tried to use radial gradient map to simulate the deformation undergone by the window panes because of pressure differences but without succes. Any ideas?
Full image : (c) Tora 2097 from Maxwell Forum, rendered in Maxwell 2.0

Re: Noise distortion / bulge map
Posted: Mon Jun 07, 2010 9:56 pm
by Soup
Aren't those distortions caused by actual distortions in the surface? Try using the 'noise map' as a bump map with low values.
Re: Noise distortion / bulge map
Posted: Mon Jun 07, 2010 10:07 pm
by dcm
I dont know ISL, i generated map in PS but as i said, i was without success, i post some test asap.
Re: Noise distortion / bulge map
Posted: Mon Jun 07, 2010 10:31 pm
by dcm
So, here are some tests. As you can see, map is doing artifacts.
Noise map :
Re: Noise distortion / bulge map
Posted: Mon Jun 07, 2010 11:50 pm
by FakeShamus
those artifacts are from the 8-bit color space of your "bulge map". ISL would probably be the best solution, if you can figure it out. but if you can generate a similar image as an .exr, in 32-bit color, it should smooth things out. even 16-bit color would improve the stair-stepping you're getting, but I heard a while back that indigo automatically converts 16-bit tiffs or png's to 8-bit internally anyway. it would be nice if we had that option though.
Re: Noise distortion / bulge map
Posted: Tue Jun 08, 2010 12:11 am
by dcm
32bit EXR solved the problem but why indigo needs 32 for bump?As i know and as i was using, 8bit was enough in other renderers. Im wondered
32bit EXR generated in PS
http://dl.dropbox.com/u/3936104/32bit%2 ... 2015mm.png
Re: Noise distortion / bulge map
Posted: Tue Jun 08, 2010 12:42 am
by CTZn
8bit was enough in other renderers
Perhaps was it because of additional texture filtering, at the cost of data loss (filters alterate texture data). What you are showing in your tests is really expected to happen with 8 bits channels.
Re: Noise distortion / bulge map
Posted: Tue Jun 08, 2010 12:54 am
by fused
This may be a bug, I reported it to nick and thomas.
Re: Noise distortion / bulge map
Posted: Tue Jun 08, 2010 1:12 am
by dcm
CTZn wrote: 8bit was enough in other renderers
Perhaps was it because of additional texture filtering, at the cost of data loss (filters alterate texture data). What you are showing in your tests is really expected to happen with 8 bits channels.
At first, i tried to use same 8bit noise map in Vray and Indigo. In vray, all was smooth, indigo makes artifacts. I was little bit dissapointed but i was using bulge maps in fry too and everything was ok. I hope its bug because its little bit annoying to make 32bit textures. Sometimes i need to use jpegs from internet which are 8bit.
Technically, if that noise map in 8bits want enough, every 8bit bump map is wrong?Probably, on wooden materials its not visible but there could be some artifacts too?
Re: Noise distortion / bulge map
Posted: Tue Jun 08, 2010 1:46 am
by StompinTom
dcm wrote:CTZn wrote: 8bit was enough in other renderers
Perhaps was it because of additional texture filtering, at the cost of data loss (filters alterate texture data). What you are showing in your tests is really expected to happen with 8 bits channels.
At first, i tried to use same 8bit noise map in Vray and Indigo. In vray, all was smooth, indigo makes artifacts. I was little bit dissapointed but i was using bulge maps in fry too and everything was ok. I hope its bug because its little bit annoying to make 32bit textures. Sometimes i need to use jpegs from internet which are 8bit.
Technically, if that noise map in 8bits want enough, every 8bit bump map is wrong?Probably, on wooden materials its not visible but there could be some artifacts too?
I ran into this exact same problem with my GH House entry, specifically the interior. The stepping was brutally obvious in a glass railing I had, even though I had a bump map that used the whole range (from black to white). I thought Indigo may do some interpolation between pixels to smooth things out since I believe that is how other programs treat their textures.
Re: Noise distortion / bulge map
Posted: Tue Jun 08, 2010 2:00 am
by OnoSendai
Indigo does indeed filter the bump map reads, so this should work. I'll look into it when I get back from holiday.
Re: Noise distortion / bulge map
Posted: Fri Aug 13, 2010 12:15 am
by dcm
any news ono ?
Re: Noise distortion / bulge map
Posted: Fri Aug 13, 2010 12:28 am
by OnoSendai
Sorry, haven't looked at the problem yet. I'll look at it tomorrow!
Cheers!
Re: Noise distortion / bulge map
Posted: Fri Aug 13, 2010 12:57 am
by dcm
Thank you master

Re: Noise distortion / bulge map
Posted: Sat Aug 14, 2010 12:15 am
by zeitmeister
Keep going for this, guys!