Material Translations

Transmutr Transmutr Alpha
1

I am not 100% sure how .mtl work or are translated but the sample OBJ I am using from CG Axis seems to be translating the materials with very low reflection settings. I just wanted to confirm that this is the .MTL file and not Transmutr.

On the leaf material it is making the reflection 0.0630.06300000101327896
(First off, can Transmutr just set this 3 decimal places?)
It seems that it is grabbing this info from the Ks values which is
Ks 0.063000 0.063000 0.063000
These numbers from what I understand are RGB values and not direction values for the reflection as a percentage.
Can Transmutr - convert those decimal values into something more closely to the RGB color it is calling for?

Here is the line from the MTL file

newmtl cgaxis_models_66_05_01
Ns 10.000000
Ni 1.500000
d 1.000000
Tr 0.000000
Tf 1.000000 1.000000 1.000000
illum 2
Ka 0.588000 0.588000 0.588000
Kd 0.500000 0.500000 0.500000
Ks 0.063000 0.063000 0.063000
Ke 0.000000 0.000000 0.000000
map_Ka maps\cgaxis_models_66_05_01.jpg
map_Kd maps\cgaxis_models_66_05_01.jpg
map_d maps\cgaxis_models_66_05_01_opacity.jpg
map_bump maps\cgaxis_models_66_05_01_bump.jpg
bump maps\cgaxis_models_66_05_01_bump.jpg

2

I’m not sure I understand. What would like to see instead of 0.063 ? What would you expect?

3

Not sure honestly. How are those decimal numbers supposed to be converted into a value for a material? Not sure I know.

When I import the OBJ into Max it creates a material with a specular value of RGB Value of Red 16, Green 16, Blue 16

When I import into Thea Studio is makes a reflectance layer with a value of Red 6, Green 6, Blue 6.

Is there no standard for converting MTL values?

4

If I plug .063 into the XYZ values for a color in the material editor in Thea, it does return a value of R16, G16, B16 - which is what Max did.

Either way, it seems way to low for a leaf reflection value.

Thea
Thea.JPG790×608 51.3 KB

5

0.063 * 255 = 16.065
So this is correct.

I’m not sure why Thea interprets it to 6. Maybe some gamma compensation?

There is not much Transmutr can do, this is what’s in the *.mtl file.

6

Yes. then that makes sense. Transmutr is doing its job correctly. The MTL file is just crappy.

Understandably, these are just meant as starter value and you tweak as needed. I was just trying to wrap my head around it all. I have a good understanding now.

7

Yeah, not surprised. CGaxis is pretty loosey-goosey with their materials. It’s amusing for example that they have one wood bitmap that they use for all their models (tinted sometimes depending on the model, but if you look, it’s the same texture in each case.)

8

It’s probably why they sell full sets for $39. Not great quality but cheap.