[Reaversword]

Hi, I'd like to unload the maxwell plugin for Maya 2012, in windows 7 64, but when I try to do it, Maya warns to me that a node of type "maxwellPreviewData" is still in the scene and for this reason, I can't unload the Maya Maxwell plugin.

I get delete the sky preview, Maxwell render globals, etc... but this one, appears I am not capable to find & delete.

Where is?. How can I select the node?. It has some generic name?.

[Mihnea Balta]

It's nowhere. This is a long-standing Maya problem: if a plug-in registers a custom data type, Maya refuses to unload it, even if that data type is no longer used in the scene. The only way to unload the Maxwell plug-in is to uncheck autoload in the plug-in manager and restart Maya.

[Reaversword]

Oo-oh, that sounds bad.

Even with Maxwell unloaded, at loading scene, Maya reloads it.

If I save the scene in .ma, for editing, I can find a line at the beginning where says: "Requires Maxwellrender 2.X.X.X". If I delete this line, Maya will load the scene without loading Maxwell, but I check Maxwell plugin, and try to uncheck, error is still there, and appears me another time the supposed node type maxwellPreviewData...

I don't know why, but Vray and Maxwell Render are not good partners inside of Maya. I need to "clean" the scene of render engines, and create two versions, one for each render engine.

Someone knows why change between Vray & Maxwell render engines cause errors in Maya?.

[Reaversword]

Its not hard to realize that the error is caused by previsualization maxwell camera system, for view materials on the viewport.

If you create, with the maxwell plugin unloaded, a cube, and save it as .ma, and then, activate maxwell plugin, open the render settings, choose Maxwell, choose Maya software again, select in Status Line, in the field of "select by name" the next: *maxw*, and delete the resultant node, we leave in the scene only the error. Saving again another .ma with a different name for compare both .ma in a text editor, reveals, at very the end of the text, the maxwell in-visor previsulization system unable to clean from the scene.

[Mihnea Balta]

No, it's not that. You can try without switching to Maxwell and back to Maya software. Just make the cube, save, load Maxwell, save again. You will see that the .ma files are identical (except for the requires line) but you still won't be able to unload the plug-in.

The custom data is indeed used for storing material previews, but it's not something that the plug-in forgets to clean up, it's a problem in the Maya SDK that we've long been aware of. You will see it mentioned in the Maya release notes, for example on page 173 in this PDF. The workaround mentioned there doesn't apply exactly like that to our plug-in, but we will try a different approach in a future build.

Anyway, it would be more useful to debug the problems that make you want to unload. What kind of errors are you getting when you try to use Vray and Maxwell in the same scene?