Octane Save material to MatLib error

[luisfos]

errors on adding octane material to library.
adding karma material builder works fine

steps:
new scenefile, H21.0.440 + octane
create new octane material builder in /mat
right click -> save material to matlib

doesn't complete, adds the thumbnail scene and gives this error:

Traceback (most recent call last):
  File "<stdin>", line 15, in <module>
  File "C:\Users/luisf/Documents/houCustom/egMatLib/scripts/python\matlib\utils\rc_calls.py", line 16, in save_material
    panel.save_asset()
  File "C:\Users/luisf/Documents/houCustom/egMatLib/scripts/python\matlib\panel\panel.py", line 663, in save_asset
    self.get_material_info_user(sel)
  File "C:\Users/luisf/Documents/houCustom/egMatLib/scripts/python\matlib\panel\panel.py", line 695, in get_material_info_user
    self.material_model.add_asset(
  File "C:\Users/luisf/Documents/houCustom/egMatLib/scripts/python\matlib\core\library.py", line 378, in add_asset
    if handler.save_node(node, new_mat.mat_id, False):
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users/luisf/Documents/houCustom/egMatLib/scripts/python\matlib\render\nodes.py", line 334, in save_node
    val = self.save_node_octane(node, asset_id, update)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users/luisf/Documents/houCustom/egMatLib/scripts/python\matlib\render\nodes.py", line 544, in save_node_octane
    return thumber.create_thumb_octane(node, asset_id)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users/luisf/Documents/houCustom/egMatLib/scripts/python\matlib\render\thumbs.py", line 276, in create_thumb_octane
    sc = thumbnail_scene.ThumbNailScene("Octane", self._preferences.ballmode)
         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users/luisf/Documents/houCustom/egMatLib/scripts/python\matlib\render\thumbnail_scene.py", line 67, in __init__
    self.build_scene()
  File "C:\Users/luisf/Documents/houCustom/egMatLib/scripts/python\matlib\render\thumbnail_scene.py", line 134, in build_scene
    self.build_lights()
  File "C:\Users/luisf/Documents/houCustom/egMatLib/scripts/python\matlib\render\thumbnail_scene.py", line 335, in build_lights
    target.parm("parmKernel").set(1)
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'NoneType' object has no attribute 'set'

[eglaubauf]

Hey Luis,

Thanks for flagging this.
Octane changed a lot of parameters/parameter names in the latest releases. Octane 2026 should be supported now on Main branch. Please let me know if works, then I'll push a proper new release.

Best,
E

[luisfos]

Hey, seems the same error on latest

Traceback (most recent call last):
  File "<stdin>", line 15, in <module>
  File "C:\Users/luisf/Documents/houCustom/egMatLib/scripts/python\matlib\utils\rc_calls.py", line 16, in save_material
    panel.save_asset()
  File "C:\Users/luisf/Documents/houCustom/egMatLib/scripts/python\matlib\panel\panel.py", line 663, in save_asset
    self.get_material_info_user(sel)
  File "C:\Users/luisf/Documents/houCustom/egMatLib/scripts/python\matlib\panel\panel.py", line 695, in get_material_info_user
    self.material_model.add_asset(
  File "C:\Users/luisf/Documents/houCustom/egMatLib/scripts/python\matlib\core\library.py", line 378, in add_asset
    if handler.save_node(node, new_mat.mat_id, False):
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users/luisf/Documents/houCustom/egMatLib/scripts/python\matlib\render\nodes.py", line 338, in save_node
    val = self.save_node_octane(node, asset_id, update)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users/luisf/Documents/houCustom/egMatLib/scripts/python\matlib\render\nodes.py", line 548, in save_node_octane
    return thumber.create_thumb_octane(node, asset_id)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users/luisf/Documents/houCustom/egMatLib/scripts/python\matlib\render\thumbs.py", line 277, in create_thumb_octane
    sc = thumbnail_scene.ThumbNailScene("Octane", self._preferences.ballmode)
         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users/luisf/Documents/houCustom/egMatLib/scripts/python\matlib\render\thumbnail_scene.py", line 67, in __init__
    self.build_scene()
  File "C:\Users/luisf/Documents/houCustom/egMatLib/scripts/python\matlib\render\thumbnail_scene.py", line 134, in build_scene
    self.build_lights()
  File "C:\Users/luisf/Documents/houCustom/egMatLib/scripts/python\matlib\render\thumbnail_scene.py", line 346, in build_lights
    target.parm("parmKernel").set(1)
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'NoneType' object has no attribute 'set'

[eglaubauf]

Could you tell me the exact version numbers of Houdini (still 440? )and and also Octane you are using? That would help a great deal. Thank you.

[luisfos]

Houdini 21.0.440 Py3.11
Octane_2025.4.0.0_Houdini_21.0.440_Studio+_Win64 (Non-solaris version)

[eglaubauf]

I just added support for Octane 2025 too, had only added 2026 before. They really like renaming their parms ;)
Could you please check from the current dev branch?

[luisfos]

on dev branch no more octane error, correctly generates the icon and mat file.
However now it does not add materials to the library. No update on reload lib. Does it work on your end?

[eglaubauf]

Hey Luis,

this seems to be working on my side. The material does get added correctly. You can also try latest commits on "dev", i just pushed a few commits today.

Could also you check if there is the Octane Renderer selected?

Also any error messages would be helpful.

[eglaubauf]

Hey Luis.

Just following up on this. I seem to not be able to recreate this issue. Could you let me know if the file is written on disk, but not loaded back in or not created at all? How does the issue surface exactly?
Thank you!

[luisfos]

Hey,
Still seems to not add the Octane materials. The files are written to disk in both img and mat. No errors or logs. Does not show the Renderer radio button Octane option either.

Here is the library.json:
library.json

[eglaubauf]

Ah yeah. So, there is a new setting in the MatLib-Preferences to enable the display of renderers. I just pushed a commit to "dev" which will enable the option automatically, if you add a specific material for it. Also the Reload issue you mentioned earlier should be taken care of now.

[luisfos]

Hey having a go with a later octane version 2026.1.0.1, unfortunately think it has some new name changes.
https://render.otoy.com/forum/viewtopic.php?t=85443

The materials thumbnails are saving incorrectly.

Also can I suggest for the Renderer radio buttons to have a default setting of "All". It is a bit confusing to not see any materials because the renderer filter is default to mtlx

[eglaubauf]

That took a bit due to IRL things. I added an "All" Section and Thumbnails should be bright again. Let me know your findings pushed to the "dev" branch. Still cannot test Octane Fully due to no license. Thank you!