I am exporting my selection to a glb using the latest babylon exporter, and the opacity maps I have assigned to the arnold shader work fine the first time…but if I export again later, it breaks. I went through the reference edits and found that babylon is generating nodes after exporting, and I have to delete them to get the transparency to work correctly. I am using babylon version 20200113.2
Ping @Drigax, in the same time @Thunda1986 could you share a quick maya project to repro ? I bet this could help @Drigax
Unfortunately I can’t share the file because it is for work but the steps to repro are:
-Select only joints and meshes of rig with arnold standard shader
-Export selected as a glb with baked animation frames
-First export is fine, but if I save the maya file after and export an edit later, the file contains those nodes in the picture and transparency stops working with the glb.
-I then have to search for mat in the reference edits of the maya outliner and delete those transparency nodes to save the file again.
I am using maya 2019.2, windows 10
My mistake 
I think the forum freaks out if you have edited messages in multiple tabs
For this issue, I think that our export settings are overriding the expected opacity settings?:
For the materials, can you check that the Opacity mode is set to Blend (for normal alpha blending)?
I checked after exporting and maya generated the babylon nodes in the hypershade and they are set to opaque instead of blend. How do I make it so these nodes aren’t generated at all after export? I mentioned in another post copy textures to output has to be checked for my export to glb to work correctly, but ideally I wouldn’t have to do that. Our current workaround is a custom maya script that we click to delete the nodes to make sure they aren’t there before exporting again.
Currently you can’t disable these nodes, but I plan to remove this functionality altogether. So far its proven to be far more trouble than its worth:
EDIT:
However, once configured the nodes should work properly and save their state between exports. We also have some additional documentation regarding them:
https://doc.babylonjs.com/resources/maya_to_gltf#babylon-material-attributes
No I have to enable that checkbox to export them, otherwise it won’t export and I don’t know why. I was wondering if it was related to this issue.
I downloaded the latest update to babylon but it is still generating transparency nodes that we have to clean up from the reference edits with a script.
If you set the node settings to Transparency mode: blend after generation, does the setting persist? I don’t quite understand why you need to remove the export setting nodes at all after they are properly configured.
So the first time I export my model with transparency, it looks correct as a glb. But babylon generates these nodes on export and we didn’t know that it was. So the next person to open the scene to edit and re-export does so, and the transparency is broken in the glb because it generated the nodes in the above picture. So it is changing something, and we found deleting the nodes from the reference list in the picture above is the fastest way to bring it back to the way it was originally. Ideally it shouldn’t be changing or adding any stuff after exporting, because it was hard to find in the first place why it was breaking.
I can understand the confusion, I agree that this was a bad feature. I still plan on removing the node generation behavior, but I can’t prioritize it over my current commitments right now. Similarly to the skinning fixes, I plan on working on this next week.
I’m more than willing to help anyone interested in fixing this check in a PR as well.
I understand, I saw in the latest build it said it fixed some things and wanted to update in case this was supposed to be one of them. Thank you for listening to feedback!