Loading...
> >

MTL - Surface parameters

Florian6CFlorian6C Posts: 1
edited March 2023 in Technical Help (nuts n bolts)

Hello everybody.

I spent a lot of time looking for information on this subject and I'm getting nowhere. I try to import small 3D object in .obj format. I found many information about texture images and map but nothing clear about coefficient. My GPU is cheap so it hard to see the impact of each parameter in Iray view.

Is there a correspondence table between the coefficients of the MTL files and those of the Surface tab ?

OBJ: Ka_Kd_Ks_Ns_d_Tf_Ni_illum...

DAZ: Base color_glossy color_Translucency weight_Glossy reflectivity_...

Thank you for your help. I know there is a lot to learn by myself but I am a bit lost and my english is a bit poor; so all these parameters are a nightmare for me.

Post edited by Florian6C on

Comments

  • markusmaternmarkusmatern Posts: 559
    edited March 2023

    Forum glitches, double post, please see below...

    Post edited by markusmatern on
  • markusmaternmarkusmatern Posts: 559
    edited March 2023

    Florian6C said:

    Hello everybody.

    I spent a lot of time looking for information on this subject and I'm getting nowhere. I try to import small 3D object in .obj format. I found many information about texture images and map but nothing clear about coefficient. My GPU is cheap so it hard to see the impact of each parameter in Iray view.

    Is there a correspondence table between the coefficients of the MTL files and those of the Surface tab ?

    OBJ: Ka_Kd_Ks_Ns_d_Tf_Ni_illum...

    DAZ: Base color_glossy color_Translucency weight_Glossy reflectivity_...

    Thank you for your help. I know there is a lot to learn by myself but I am a bit lost and my english is a bit poor; so all these parameters are a nightmare for me.

    Never thought about the actual parameters. IMHO the most important stuff are the maps, that are in the MTL file.

    However I found some descriptions here: http://paulbourke.net/dataformats/mtl/

    As an example I dowloaded the 1K Blender version of this free screwdriver asset.

    I used Blender to convert it to the OBJ format.

    This is the resulting MTL file:

    # Blender 3.3.1 MTL File: 'flathead_screwdriver_1k.blend'
    # www.blender.org

    newmtl flathead_screwdriver
    Ka 1.000000 1.000000 1.000000
    Ks 0.500000 0.500000 0.500000
    Ke 0.000000 0.000000 0.000000
    Ni 1.450000
    d 1.000000
    illum 2
    map_Kd textures/flathead_screwdriver_diff_1k.jpg
    map_Ns textures/flathead_screwdriver_rough_1k.exr
    map_refl textures/flathead_screwdriver_metal_1k.exr
    map_Bump -bm 1.000000 textures/flathead_screwdriver_nor_gl_1k.exr

    I imported the OBJ into Daz Studio and two of the maps were already loaded:

    map_Kd was set to IRAY►Base►Diffuse►Reflection►Base Color

    map_Bump was set to IRAY►Base►Bump►Base Bump , but with the parameter set to 0

    The other two were missing.

    I changed the following:

    I removed the map from IRAY►Base►Bump►Base Bump and instead put it into IRAY►Base►Bump►Normal Map

    I put the map from map_refl into the following property: IRAY►Base►Diffuse►Reflection►Metallicity and set the value to 1

    I put the map from map_Ns into the following property: IRAY►Base►Glossy►Reflection►Glossy Roughness and set the value to 1

    This example also shows the most important maps for materials that are not transparent.

    I hope this helps!

     

    Screwdriver.png
    934 x 1246 - 1M
    Post edited by markusmatern on
  • Florian6CFlorian6C Posts: 1

    I just saw your reply. Thanks you !

    It's practical so it's going to help me a lot smiley

  • markusmaternmarkusmatern Posts: 559
    edited March 2023

    Florian6C said:

    I just saw your reply. Thanks you !

    It's practical so it's going to help me a lot smiley

    Glad I was able to help you out! Please do not hesitate if you have further questions!

    Post edited by markusmatern on
  • pjwhoopie@yandex.compjwhoopie@yandex.com Posts: 793

    Funny this should be an ongoing thread... I am dealing with this exact issue now.  I will dive in, and chime in with some questions too, if its ok?

     

Sign In or Register to comment.