To see a texture in viewport from a object with Arnold shader I need to create a standard C4D material and assign it temporarly... Maybe exists a better method to avoid this process, someone know a better solution?
There is an Arnold Viewport slot in the shader network editor. Connecting an image shader or a standard_surface shader should appear in the viewport.
It's a bit slower than the C4D material though, unfortunately the SDK is limited and I could not find a better way so far.
follow up question: how do I make transparent textures (textures with transmission) appear in the viewport?
Unfortunately viewport display of the Arnold shaders are currently very limited and transparency or transmission is not supported.
Do you see red textures in the viewport, when it does not work? Or just nothing appears?
Yes! Red in the viewport. Plus I don't know how to make them high-res in the viewport. They are always quite low.
I may have a fix for that coming in the next release. I also hope that I can improve the implementation a bit for simple cases.
You can change the resolution via the Texture preview size parameter of the Arnold Material.
I see - its in the material tab. Works perfectly. That's bugged me for age I must ask more questions on here!