Indigo Renderer Forum

Posted: **Sat Dec 30, 2006 5:57 am**

Hi all,

I am working on a bump map material:

The material number 1 is defined like this:

<material>
		<name>alu_bumped.2</name>
		<phong>
			<nk_data>nkdata/Ag.nk</nk_data>
			<exponent>150.000</exponent>
			<bump_map>
				<uv_set>uv</uv_set>
				<path>noisemi8.jpg</path>
				<gain>0.0010000</gain>
				<exponent>1.000000</exponent>
			</bump_map>
		</phong>
</material>

The material number 2 is defined like this:

Code: Select all

<material>
		<name>Alu_bumped</name>
		<phong>
			<nk_data>nkdata/Al.nk</nk_data>
			<exponent>50.000</exponent>
			<bump_map>
				<uv_set>uv</uv_set>
				<path>noisemi8.jpg</path>
				<gain>0.002000</gain>
				<exponent>1.000000</exponent>
			</bump_map>
		</phong>
</material>

It is really hard to have a good result, and I would like to have your opinion about the different parameters:
exponent of the materrial
gain of the bump
what means the exponent of the bump_map?

Thanks in advance.

Regards, Phil

Posted: **Sat Dec 30, 2006 8:37 am**

Correct me if I'm wrong, but I think the exponent is a gamma correction, and since bump mapping needs a scalar not a colour, its good to let it at 1. As for good settings I can't tell you because my uvs get screwed up between Maya and Indigo

Posted: **Mon Jan 01, 2007 2:59 am**

Hi CTZn,

[img]

http://img264.imageshack.us/img264/8817 ... 665ba1.png [/img]

but I think the exponent is a gamma correction

I do not know

<nk_data>nkdata/Ag.nk</nk_data>
<exponent>150.000</exponent>

this exponent seems to have an influence on the shininess

<gain>0.002000</gain>
<exponent>1.000000</exponent>

I have no idea what this means

Now the material are defined like this:

material 1:

<material>
<name>alu_bumped.2</name>
<phong>
<nk_data>nkdata/Al.nk</nk_data>
<exponent>40.000</exponent>
<bump_map>
<uv_set>uv</uv_set>
<path>noisemi8.jpg</path>
<gain>0.0012</gain>
<exponent>0.9</exponent>
</bump_map>
</phong>
</material>

material 2:

<material>
<name>Alu_bumped</name>
<phong>
<nk_data>nkdata/Al.nk</nk_data>
<exponent>50.000</exponent>
<bump_map>
<uv_set>uv</uv_set>
<path>noisemi8.jpg</path>
<gain>0.0012000</gain>
<exponent>1.000000</exponent>
</bump_map>
</phong>
</material>

This seems to be acceptable now

Regards, Phil

Posted: **Mon Jan 01, 2007 4:26 am**

Phil wrote:
but I think the exponent is a gamma correction
I do not know

I'm pretty sure

Posted: **Wed Jan 03, 2007 7:33 am**

Hi everybody,

I made some new tests and investigations.
I have some new problems.

(I increased The resolution to 1280 x 960, we only see some extract here

)

This is what I get about one hour:

The bumps effect looks good for me.

This is the result after about 2 days

And here is the problem, the bump effect seems to disappear

Another problem is that with this resolution we see a smoothing problem.
I simply forgott to turn autosmooth on in blender.

[edit]
I am not a blender specialist, who can tell me the difference between autosmooth and set Smooth, I did not understand this.
[edit]

The material are defined like this now:

Code: Select all

<material>
		<name>Alu_bumped</name>
		<phong>
			<nk_data>nkdata/Al.nk</nk_data>
			<exponent>6.000</exponent>
			<bump_map>
				<uv_set>uv</uv_set>
				<path>noisemi8.jpg</path>
				<gain>0.0012000</gain>
				<exponent>0.5</exponent>
			</bump_map>
		</phong>
	</material>

	<material>
		<name>alu_bumped.2</name>
		<phong>
			<nk_data>nkdata/Al.nk</nk_data>
			<exponent>5.000</exponent>
			<bump_map>
				<uv_set>uv</uv_set>
				<path>noisemi8.jpg</path>
				<gain>0.0009</gain>
				<exponent>0.0</exponent>
			</bump_map>
		</phong>
	</material>

This is an extract of the bump map the original size is 2000x2000

CTZN wrote:

I'm pretty sure

Well you must really have good informations, nothing to read about this in the reference manual, and nothing in the blender indigo tutorial.

the exponent is a gamma correction

good, it is a gamma corretion but tell me more, and why is it called exponent and not gamma

Does anybody made some good experience with bump mapping (not sand blasting)

Thanks in advance for all remarks, and so on.

Regards, Phil

Posted: **Wed Jan 03, 2007 11:45 am**

set smooth = all selected is smooth
Autosmooth = smooth only faces that are who's normals differ less than the maxangle degree..

Posted: **Thu Jan 04, 2007 7:07 am**

Hi Ricky,

thanks, this helped me, I also discovered that I had a lot of doubles.
I only import obj in blender, so I have to learn more with blender.

This is a new test, I found an interesting post from Filipo in the 3DS max section I think.
I increase the bumpiness factor to 100 now.

that is what comes out after 4 minutes rendering.

I am really shocked, I have no idea what will be the result.
(it is now 15 minutes and the result is still so black)

Perhaps the bumpiness will never be a finished artwork

Regards, Phil

Indigo Renderer Forum

Bump map material

Bump map material