2.44 Material Connection Problem after re-exporting OBJ file

[Refracty]

Hi,

I was running into the following issue:
I have added new materials in Rhino 5 and after I updated the obj in Octane there are 2 problems:

1. I lost the connection to some old materials that haven't been changed.
2. Some material nodes are connected with the wrong obj material inputs and I can not remove the connection by 'pulling the connection rope'.

When I update the obj in 2.43 I have no problems.
It seems that the new build might handle material orders in the mtl file differently and that causes problems. But this is just a guess.
Any help?

Cheers
Refracty

[abstrax]

Hi,

I was running into the following issue:
I have added new materials in Rhino 5 and after I updated the obj in Octane there are 2 problems:

1. I lost the connection to some old materials that haven't been changed.
2. Some material nodes are connected with the wrong obj material inputs and I can not remove the connection by 'pulling the connection rope'.

When I update the obj in 2.43 I have no problems.
It seems that the new build might handle material orders in the mtl file differently and that causes problems. But this is just a guess.
Any help?

Cheers
Refracty

As far as I know there haven't been any changes, beside the Unicode changes. To fix issue, could you please send us the scene to support (at) refractivesoftware.com and detailed description to reproduce the problem?

Thanks,
Marcus

[necko77]

i had a similiar problem and it was with blender 2.56
I was doing some updates on a model and when i updated obj in octane everything went white, so i had to assign all materials again.
Its not happaning all the time, but only sometimes. I was adding ivy in my model.
i will try to reproduce problem again and post it here. Here is pic of my model

[Refracty]

Yeah, i tried it again and then it was working.
But maybe it was because I might have saved the scene as Rhino 4 instead of 5.
This might cause changes in the material definitions but I am not 100% sure if I did this because this happened in a long and tough night.
When I experience the same again, I try to track / screenshot / explain it in detail and provide a sample scene.
Thanks
Refracty

[abstrax]

Yeah, i tried it again and then it was working.
But maybe it was because I might have saved the scene as Rhino 4 instead of 5.
This might cause changes in the material definitions but I am not 100% sure if I did this because this happened in a long and tough night.
When I experience the same again, I try to track / screenshot / explain it in detail and provide a sample scene.
Thanks
Refracty

Thanks a lot. Meanwhile I will try to reproduce the problem myself.

Cheers,
Marcus

[Refracty]

There is one problem I have experienced after updating a 3D model in Rhino.
I don't think it is a bug in octane. Maybe it is depending how octane reads and builds up the scene constructions.
So when I update the linked obj-file in the ocs file. Lets say I rename model1.obj to model2.obj (the updated version).
Then octane makes weired connections with the materials. There are new materials in the obj scene and octane doesn't understand the new order.
Reloading the mesh in Octane itself works but takes so long opening the previous scene that you won't need anyway.
So it would be cool to have the possibility to swap the obj with a text editor and still keep the right material connections of updated geometry and materials (obj/mtl).
Is this possible in the future?

[GeoPappas]

There is one problem I have experienced after updating a 3D model in Rhino.
I don't think it is a bug in octane. Maybe it is depending how octane reads and builds up the scene constructions.
So when I update the linked obj-file in the ocs file. Lets say I rename model1.obj to model2.obj (the updated version).
Then octane makes weired connections with the materials. There are new materials in the obj scene and octane doesn't understand the new order.
Reloading the mesh in Octane itself works but takes so long opening the previous scene that you won't need anyway.
So it would be cool to have the possibility to swap the obj with a text editor and still keep the right material connections of updated geometry and materials (obj/mtl).
Is this possible in the future?

If I understand you correctly, a workaround for this is to edit the OCS file (with a simple text editor like Notepad) and replacing the text "model1.obj" with "model2.obj". It should appear in two places in the OCS file.

Note: Make a backup of the OCS file before you start to play with it.

[abstrax]

There is one problem I have experienced after updating a 3D model in Rhino.
I don't think it is a bug in octane. Maybe it is depending how octane reads and builds up the scene constructions.
So when I update the linked obj-file in the ocs file. Lets say I rename model1.obj to model2.obj (the updated version).
Then octane makes weired connections with the materials. There are new materials in the obj scene and octane doesn't understand the new order.
Reloading the mesh in Octane itself works but takes so long opening the previous scene that you won't need anyway.
So it would be cool to have the possibility to swap the obj with a text editor and still keep the right material connections of updated geometry and materials (obj/mtl).
Is this possible in the future?

Yes I found the problem, but we couldn't fix it in time since it's a bit convoluted: When we load an OCS file we load the OBJ/MTL files in a way that assumes, that they have NOT been changed. If they got changed and the materials have been renamed or reordered, everything goes bonkers. That's because we don't do the relinking step then. Only when the exporter specifies the relink option, a relinking is done for the specified mesh. Or when you use the reload button in the mesh node.

In the future we will change it in a way, that it always relinks all meshes using the material names, but as said before it's a quite intrusive change we didn't want to do now to avoid breaking other things.

-> If you plan to change the mesh and add/remove materials, do NOT just change the OBJ/MTL and reopen the OCS file. There are only two ways known to me at the moment:

a) Using the exporter plugins: Just change your scene and click on "Render". This should update the OBJ/MTL file combo and force Octane to correctly relink materials via their names.

b) Without using an exporter plugin: Do it always in that order: Open the OCS file. Then update the OBJ/MTL files. Then click on the "Reload" button of your mesh node and select the new OBJ file. The "Reload" button does also do a relinking step.

Again, never ever just change the OBJ/MTL files of an already existing OCS file and expect the OCS file to load correctly, after you have done the change.

I hope that helps.

Cheers,
Marcus

[colin]

Again, never ever just change the OBJ/MTL files of an already existing OCS file and expect the OCS file to load correctly, after you have done the change.

so, if i read this correctly, until said issue gets fixed, we can only use the "export obj/mtl only" command if we're not introducing new materials and objects?

[abstrax]

Again, never ever just change the OBJ/MTL files of an already existing OCS file and expect the OCS file to load correctly, after you have done the change.

so, if i read this correctly, until said issue gets fixed, we can only use the "export obj/mtl only" command if we're not introducing new materials and objects?

Yes, except you use the second method: Open OCS file, reexport using "Export OBJ/MTL" and then reload via the "Reload" button of the mesh node in Octane. That should work, too.

Cheers,
Marcus