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help with orange material

Posted: Wed Mar 11, 2009 7:10 am
by carbon
does have anyone idea about these dark spots?
thanks i advance..
c.

material:

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	<material>
		<name>previewmaterial</name>
		<phong>
			<exponent>
				<constant>5000</constant>
			</exponent>
			<ior>1.37</ior>
			<texture>
				<path>tex-orange/orange1_diff.png</path>
				<uv_set>default</uv_set>
				<exponent>2.200000</exponent>
				<a>0</a>
				<b>1</b>
				<c>0</c>
			</texture>
			<texture>
				<path>tex-orange/orange1_spec.png</path>
				<uv_set>default</uv_set>
				<exponent>2.200000</exponent>
				<a>0</a>
				<b>5000</b>
				<c>500</c>
			</texture>
			<texture>
				<path>tex-orange/orange1_disp.png</path>
				<exponent>2.200000</exponent>
				<uv_set>default</uv_set>
				<b>0.0010</b>
			</texture>
			<texture>
				<path>tex-orange/orange1_bump.png</path>
				<exponent>2.200000</exponent>
				<uv_set>default</uv_set>
				<b>0.0005</b>
			</texture>
			<diffuse_albedo>
				<texture>
					<texture_index>0</texture_index>
				</texture>
			</diffuse_albedo>
			<exponent>
				<texture>
					<texture_index>1</texture_index>
				</texture>
			</exponent>
			<displacement>
				<texture>
					<texture_index>2</texture_index>
				</texture>
			</displacement>
			<bump>
				<texture>
					<texture_index>3</texture_index>
				</texture>
			</bump>
		</phong>
	</material>
mesh:

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	<mesh>
		<name>preview_sphere</name>
		
		<max_num_subdivisions>2</max_num_subdivisions>
		<subdivide_pixel_threshold>0.0</subdivide_pixel_threshold>
		<subdivide_curvature_threshold>0.0</subdivide_curvature_threshold>
		<subdivision_smoothing>true</subdivision_smoothing>
...

Posted: Wed Mar 11, 2009 4:42 pm
by CTZn
Not sure...

First think could be to reverse the texture <b> parameter for displacement, and maybe for bump too (oranges feature small holes rather than small bumps). Also you may prefer to use a linear exponent (1) rather than a gamma corrected one for scalar textures (bump, displacement, phong exponent). They are not colour information but pure parameters data, usually one doesn't want to distort them, but that's still an option.

When you are happy with the <b> value for the displacement texture, can you test setting a <c> value ? In the range [-b;-b/2]... this should at least have an impact on the folds around the logo. I don't know what a good "default" value could be for the <c> parameter of a displacement texture in Indigo, you are free to test :)

I think the bottom right black spot is from the albedo texture, the ones around the silhouette are caused by shading normals, you can try setting <subdivision_smoothing> to 'false'.

Posted: Fri Mar 13, 2009 2:54 am
by carbon
thanks for comments CTZn, i knew that you will reply
now i see it too, displacement map is inverted, i inverted it and i though i was doing fine, but it was late at night, so..
i am testing new approch with phong/transmitter blend.. if it will be fine i'll post it in material library, which is sadly pretty abandoned these days :(

Posted: Sun Mar 15, 2009 9:32 pm
by Stur
Even with these small black areas it's still awesome !

Where does your map come from ? Is it a painting or a photo ? Can we see it ?