Brushed Aluminum

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ozzie
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Brushed Aluminum

Post by ozzie » Mon Jan 12, 2009 11:43 pm

so, this time I've got new problem which (as usually) I don't know how to solve :/
not sure is there a problem with bump map or in other setting :/

I'm trying to make brushed aluminum and I don't know how to make it right. This is what I've done so far.
I was trying to do exactly as it was done in here:

http://www.indigorenderer.com/joomla/fo ... ht=brushed

I just used different map, and what ever I'll do I still have those black lines. I was trying to make it with 0.005 up to 0.01 bump but still nothing :/
HELP! :)

Code: Select all

<material>
		<name>Material</name>
		<phong>
			<exponent>
				<constant>10000</constant>
			</exponent>
			<ior>1.60838</ior>
			<nk_data>nkdata\al.nk</nk_data>
			<texture>
				<path>I:\Documents and Settings\Ozzie\Pulpit\HT_Brush.jpg</path>
				<uv_set>uv</uv_set>
				<exponent>2.200000</exponent>
				<a>0.001</a>
				<b>0.001</b>
				<c>0.001</c>
			</texture>
			<diffuse_albedo>
				<constant><rgb>
					<rgb>0.8 0.8 0.8</rgb>
					<gamma>2.2</gamma>
				</rgb></constant>
			</diffuse_albedo>
			<bump>
				<texture>
					<texture_index>0</texture_index>
				</texture>
			</bump>
		</phong>
	</material>
Attachments
im1231759051.png
render
im1231759051.png (540.95 KiB) Viewed 6392 times
HT_Brush.jpg
material
HT_Brush.jpg (1.28 MiB) Viewed 6399 times

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Zom-B
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Post by Zom-B » Tue Jan 13, 2009 12:15 am

just use the B value for scaling the bump, A & C are more complicated to explain let them on 1, your line problem seems to come from there :)

try not to use a BumpMap, but a exponent Map for your material with a B value of about 100.
polygonmanufaktur.de

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CTZn
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Post by CTZn » Tue Jan 13, 2009 1:03 am

Two things: as Zom-B mentioned the B (gain) value is way too strong, and bump technology is not well suited to work on aliased textures, blur it ! Actually black on white is worse than everything, that's where the issue comes from mostly. Bump needs shades to define a surface normal direction.

For bump and displacement a texture exponent of 1 is generally wanted, since exponent will change the bump slope. 2.2 is good for wavelength- dependent parameters (aka colors).

edit: ah well you beat me at it...
Last edited by CTZn on Tue Jan 13, 2009 1:09 am, edited 2 times in total.

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ozzie
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Post by ozzie » Tue Jan 13, 2009 1:04 am

I've used this same texture, but changed a little bit.
Thirst two objects from left are made just as it shown in blendigo, the last cube is just an PHONG al.nk with exponent map with B 100

I hope it will be fine :/

The Aluminum2 material code:

Code: Select all

	<material>
		<name>aluminum2</name>
		<phong>
			<exponent>
				<constant>10000</constant>
			</exponent>
			<ior>1.60838</ior>
			<nk_data>nkdata\Al.nk</nk_data>
			<texture>
				<path>I:\Documents and Settings\Ozzie\Pulpit\HT_Brush2.jpg</path>
				<uv_set>uv</uv_set>
				<exponent>2.200000</exponent>
				<a>0</a>
				<b>100</b>
				<c>1</c>
			</texture>
			<diffuse_albedo>
				<constant><rgb>
					<rgb>0.8 0.8 0.8</rgb>
					<gamma>2.2</gamma>
				</rgb></constant>
			</diffuse_albedo>
			<exponent>
				<texture>
					<texture_index>0</texture_index>
				</texture>
			</exponent>
		</phong>
	</material>
Attachments
HT_Brush2.jpg
material
HT_Brush2.jpg (840.52 KiB) Viewed 6368 times
im1231763315.png
render
im1231763315.png (867.99 KiB) Viewed 6370 times

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SmartDen
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Post by SmartDen » Tue Jan 13, 2009 1:51 am

i think one can make such brushed metal with shaders. so you don't need any textures
Check normals, dude!

Image
Image

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ozzie
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Post by ozzie » Tue Jan 13, 2009 2:30 am

But.. you must know how to write them :) and I'm "OUT" at shader's topic :)

Schosch
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Post by Schosch » Tue Jan 13, 2009 7:39 am

Code: Select all

def eval() real :
						fbm(dot(getTexCoords(0)*1000.0, vec2(0.0, 0.75)), 4)*0.0003
This shader stretches the fbm noise in a certain direction.

The factor after getTexCoords (1000.0) controls the general noise scale (the higher the smaller), the values of vec2 control the direction and the length of the scratches, the value after vec2 (4) sets the number of noise octaves (and thereby the amount of detail) and the factor at the end (0.0003) controls the depth of the bump effect.

I have added this to the MatDB: Brushed aluminium
Attachments
im1231784611.png
see above
im1231784611.png (391.49 KiB) Viewed 6301 times

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ozzie
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Post by ozzie » Tue Jan 13, 2009 8:31 am

Schosch wrote:

Code: Select all

def eval() real :
						fbm(dot(getTexCoords(0)*1000.0, vec2(0.0, 0.75)), 4)*0.0003
This shader stretches the fbm noise in a certain direction.

The factor after getTexCoords (1000.0) controls the general noise scale (the higher the smaller), the values of vec2 control the direction and the length of the scratches, the value after vec2 (4) sets the number of noise octaves (and thereby the amount of detail) and the factor at the end (0.0003) controls the depth of the bump effect.

I have added this to the MatDB: Brushed aluminium
That's it? just one line? You must be joking!?

Schosch
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Post by Schosch » Tue Jan 13, 2009 8:42 am

Actually there are two lines... :P
No, really, that is everything, you can try it out for yourself if you didn't already.

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ozzie
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Post by ozzie » Tue Jan 13, 2009 8:44 am

Schosch wrote:Actually there are two lines... :P
No, really, that is everything, you can try it out for yourself if you didn't already.
all ready done it :)

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ozzie
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Post by ozzie » Tue Jan 13, 2009 9:03 am

Schosch wrote:Actually there are two lines... :P
No, really, that is everything, you can try it out for yourself if you didn't already.
Why I'm not so clever as you :/ :( buuu ;(

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Post by Juniorsatan » Tue Jan 13, 2009 9:34 am

Whenever i see these Materials who were build by 2 lines code, I got a missin' feeling of a nice & easy tutorial which explaines the conecept and the setup of the functions etc. Damn it, nice to see that we can build those mats without any texture.

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ozzie
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Post by ozzie » Tue Jan 13, 2009 10:20 am

Yes, but if there would be some tutorial for it like "hello word" the live would be much easier:)
"Hello Word" in Indigo :/ Sound nice :)

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Kram1032
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Post by Kram1032 » Wed Jan 14, 2009 9:47 am

Interesting would be, if another bfm-layer (with different seed) somehow controls that stretch, "randomizing the stretch-distance" - if that's at all possible^^

Schosch
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Post by Schosch » Thu Jan 15, 2009 6:32 am

Interesting would be, if another bfm-layer (with different seed) somehow controls that stretch, "randomizing the stretch-distance" - if that's at all possible^^

Code: Select all

def eval() real :
						fbm(dot(getTexCoords(0)*1000.0, vec2(0.0, clamp(noise(getTexCoords(0)), 1.0, 5.0))), 4)*0.0003
I've changed the shader code so that the scratches now have a more or less random length.
Attachments
im1231949024.jpg
im1231949024.jpg (89.57 KiB) Viewed 6164 times

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