Specularity/Hardness reference for Blender

Get feedback from others on your works in progress
Post Reply
14 posts • Page 1 of 1
User avatar
kououken
Posts: 11
Joined: Tue Oct 31, 2006 2:24 pm
Location: Kyushu, Japan

Specularity/Hardness reference for Blender

Post by kououken » Mon Nov 06, 2006 10:38 pm

I made this test image to get a feel for the range of specularity and hardness selectable from blender. Makes it easier to pick settings for say, dry silk, or slimy frogskin, etc. You can also see how specularity settings above 1.0 don't make the reflection any sharper, but the consecutive reflections get out of control quickly.

Hope this helps someone. I'm just not patient enough to do the materials in the xml by hand! :shock: Are there any other renders to reference? Like changing IOR, or transparency for example?

Image
-KouOuKen

User avatar
tungee
Posts: 482
Joined: Mon Jul 03, 2006 8:17 pm
Location: Gießen Germany

Post by tungee » Mon Nov 06, 2006 10:39 pm

tampopo , hanna bi ,ran ...
that looks great, but what means hardness? what parameter is meant?
Music has the right to children!

lego
Posts: 99
Joined: Sat Oct 14, 2006 7:29 am

Post by lego » Mon Nov 06, 2006 10:55 pm

hardness = exponent

User avatar
skypa
Posts: 103
Joined: Tue Oct 24, 2006 11:38 pm
Location: Germany / Berlin

Post by skypa » Mon Nov 06, 2006 10:58 pm

Great reference, thank you for that. Getting the spec and hardness right has always been a little try&error-ish. :)

User avatar
OnoSendai
Developer
Posts: 6241
Joined: Sat May 20, 2006 6:16 pm
Location: Wellington, NZ
Contact:

Post by OnoSendai » Mon Nov 06, 2006 11:17 pm

And what is specularity in the blender exporter?
I have a funny feeling it's fresnel_fraction, in which case, it shouldn't go above 1 :)

lego
Posts: 99
Joined: Sat Oct 14, 2006 7:29 am

Post by lego » Mon Nov 06, 2006 11:46 pm

OnoSendai wrote:And what is specularity in the blender exporter?
I have a funny feeling it's fresnel_fraction, in which case, it shouldn't go above 1 :)
mmm that's strange!
I always thought that indigo specularity was taken from blender specular color!
but I did a test and I saw that it takes in consideration the specularity slider too...
so if I set spec color to 0.8 0.8 0.8 and specularity to 0.5, I get an indigo specularity of 0.203 0.203 0.203.
If I set spec color 0.8 0.8 0.8 and specularity to 2, I get an indigo specularity of 4.x 4.x 4.x :shock:
maybe an exporter bug? I'm using the last version

User avatar
kououken
Posts: 11
Joined: Tue Oct 31, 2006 2:24 pm
Location: Kyushu, Japan

Post by kououken » Tue Nov 07, 2006 12:51 am

Well shoot.. here I thought I had finally figured out how things worked.

What would the settings in blender be, for example, for a perfect mirror? :(
-KouOuKen

User avatar
OnoSendai
Developer
Posts: 6241
Joined: Sat May 20, 2006 6:16 pm
Location: Wellington, NZ
Contact:

Post by OnoSendai » Tue Nov 07, 2006 12:55 am

kououken wrote:Well shoot.. here I thought I had finally figured out how things worked.

What would the settings in blender be, for example, for a perfect mirror? :(
<specular>1 1 1</specular>
<diffuse>0 0 0</diffuse>

lego
Posts: 99
Joined: Sat Oct 14, 2006 7:29 am

Post by lego » Tue Nov 07, 2006 1:01 am

in the exporter the specularity is set as this

colGamma(mat.specB*specfac)*SpecularGain.val

for each color

I think specfac is the specular slider
I don't know what speculargain.val is...

I'll try to use just

colGamma(mat.specB)

zuegs
Posts: 380
Joined: Tue Jun 27, 2006 5:46 pm
Location: switzerland

Post by zuegs » Tue Nov 07, 2006 1:26 am

SpecularGain.val is not used currently and is constantly set to 1.0

so specularity is defined as following:

Red = colGamma(mat.specR*specfac)
Green = colGamma(mat.specG*specfac)
Blue = colGamma(mat.specB*specfac)
:wink:

User avatar
OnoSendai
Developer
Posts: 6241
Joined: Sat May 20, 2006 6:16 pm
Location: Wellington, NZ
Contact:

Post by OnoSendai » Tue Nov 07, 2006 1:30 am

Well... whoevers on blender duty.. they need to clamp each component of the specular colour to the range [0, 1]. :)

lego
Posts: 99
Joined: Sat Oct 14, 2006 7:29 am

Post by lego » Tue Nov 07, 2006 1:41 am

zuegs wrote:SpecularGain.val is not used currently and is constantly set to 1.0

so specularity is defined as following:

Red = colGamma(mat.specR*specfac)
Green = colGamma(mat.specG*specfac)
Blue = colGamma(mat.specB*specfac)
:wink:

Are you sure?
I modified the script leaving

colGamma(mat.specR)*SpecularGain.val
I set a spec color of 0.4xx and hit export
in the xml I had a specularity that was roughly 0.25 times the one set in blender!
And I don't get the need to use the specfac value in that expression! it would be much more intuitive to have spec col slider --> indigo specularity

User avatar
DaveC
Posts: 596
Joined: Mon Sep 11, 2006 12:20 am
Location: The Tottenham, London, UK
Contact:

Post by DaveC » Tue Nov 07, 2006 2:49 am

How very odd!! Last night I posted a final render inspired by exactly the same idea as this image. You can see it at this link: http://www.indigorenderer.com/joomla/in ... temId=3406
I would have done one the same as this one, but I didn't have the patience! lol
The hardest part of BEING yourself is FINDING yourself in the first place...
http://thebigdavec.googlepages.com

zuegs
Posts: 380
Joined: Tue Jun 27, 2006 5:46 pm
Location: switzerland

Post by zuegs » Tue Nov 07, 2006 2:56 am

@lego:
as long you have the "colGamma()" function in the formula you do a inverse gamma correction dependent of the col-exp slider in the exporter... you can set col-exp slider to 1.0 or remove "colGamma()" to match values between Blender and Indigo.

@OnoSendai:
you are right, will try to remember this for next release :oops: exporter is still very experimental :wink:

Post Reply
14 posts • Page 1 of 1

Who is online

Users browsing this forum: No registered users and 29 guests