Why when I edit Arnold materials do the material previews go black in 3dsMax?

[nano_langenheim]

I find this happens quite often - and had assumed I am either doing something wrong with my lighting or I am upsetting the 'energy balance' of the materials (I also don't know how to correct this if that is the case)). In a fresh max scene - I make my Arnold materials - they preview fine, I add them to a multisub, they look fine - but as soon as I turn the Specular down they start turning into patters and then go black. This is also true of new Arnold materials that I make in the scene - I don't seem to be able to get the previews back. It still renders fine - but I like to have the previews.....

Any clues?

[madsd · Accepted solution]

The thumbnails are not working correctly in all cases, also - if you render then thumbnails will go black, because the license is used to the render, since the thumbnails are rendering, it takes over.
You cant have both on same time.

What you should do instead, is use the active shade render which is a realtime window, and have that open when you work with the materials, that will always output the combined effort to your probe mesh in the scene.

If you stop rendering, and rightclick the black material and pick "update" while no render is going, it will come back, if it's still black, it means that the shader construct is not able to print the output the thumbnail, which means that the active shade workflow is the most attractive in almoste all cases.

Small warning, using thumbnail rendering will slow down your experience significantly in all aspects, as the entire node tree will spend time updating thumbnails, if you use large bitmaps it can take a very long time, you could have spend on actual work. You can disable the thumbnails in the lower left corner of the slate editor - I always have it off, unless I am writing an OSL shader and just have that single shader in the scene ( not even connected to items in scene )

[pproestos]

Thanks for the reminder Mads... yes I also thought that enabling thumbnail rendering slows down everything actually with no reason... as we evolve: you the programmers, we the users, I think we all understand that everything will be done in active shade for previewing. It's a professional and "the" tool for a designer...

[nano_langenheim]

Thanks Mads,

that is making a huge difference to the rendering speed -