Rhino 8 | Material names issue when exporting OBJ

Hi there,

I wanted to bring up an issue I’ve been having with Rhino version 8.12.24261.130001. When I export OBJ mesh files, the .mtl files that are generated don’t have the correct material names. This has been a bit of a hassle when I try to import these files into other software for further processing or rendering.

I’ve attached an example file to show what’s happening. If anyone has any insights or suggestions on how to fix this, I’d really appreciate it.

Export-OBJ-materials-bug.3dm (126.3 KB)

This is the exported .mtl file:
8.12.24261.130001.zip (1.3 KB)

# Rhino
newmtl Default
Ka 0.0000 0.0000 0.0000
Kd 0.0000 0.0000 1.0000
Ks 0.8000 0.8000 0.8000
Tf 1.0000 1.0000 1.0000
d 1.0000
Ns 204.0000
Ni 1.5200

This is the expected result (exported with version 8.8.24149.15001):
8.8.24149.15001.zip (1.3 KB)

# Rhino
newmtl Blue
Ka 0.0000 0.0000 0.0000
Kd 0.0000 0.0000 1.0000
Ks 0.8000 0.8000 0.8000
Tf 0.0000 0.0000 0.0000
d 1.0000
Ns 204.0000
newmtl Green
Ka 0.0000 0.0000 0.0000
Kd 0.0000 1.0000 0.0000
Ks 0.8000 0.8000 0.8000
Tf 0.0000 0.0000 0.0000
d 1.0000
Ns 204.0000
newmtl Red
Ka 0.0000 0.0000 0.0000
Kd 1.0000 0.0000 0.0000
Ks 0.8000 0.8000 0.8000
Tf 0.0000 0.0000 0.0000
d 1.0000
Ns 204.0000

Thanks for your help!

Bump

Hi Julio -

I see that here with Physically Based materials
RH-84157 File IO: Physically Based Material to OBJ
-wim

1 Like

Hi, has there been found a solution to this? @Julio
It has been happening to me ever since I updated to the latest version for Mac.

Hi, not yet. You can follow the issue progress from here RH-84157
As a workaround you can change the material type from Physically Based to Plaster, or downgrade to a previous version.

RH-84477 is fixed in Rhino 8 Service Release 14

RH-84157 is fixed in Rhino 8 Service Release 14

I’m sorry to reopen this but I’m still having the same issue in the 8.16.25014.10001, 2025-01-14 version
@brian @wim

Hi Julio -

When I now download your file…

… select all objects, and export to OBJ, the resulting .mtl file contains the blue, green and red materials.


Materials Test.mtl (450 Bytes)

What are you doing differently?
-wim

Hello Wim,
Thank you for your response.

I’m having trouble identifying what I’m doing wrong. When I try to export the OBJ from the following file:

I can see the different materials correctly.

However, when I tried a different file with various geometries and applied the same Physical Based materials (red, green, and blue), the export result was as follows:
test-mtl.mtl (157 Bytes)

# Rhino
newmtl Default
Ka 0.0000 0.0000 0.0000
Kd 0.9804 0.9804 0.9804
Ks 1.0000 1.0000 1.0000
Tf 1.0000 1.0000 1.0000
d 1.0000
Ns 0.0000
Ni 1.0000

You can find the file here: Export-OBJ-materials-bug-2.3dm (10.8 MB)

Thanks for the support!

Hi Julio -

Thanks. I’ve added that file to RH-84157 File IO: Physically Based Material to OBJ
-wim

1 Like