heya, I am new to this forum, not especially new to Zbrush but still very much in the learning stage. I have a few questions about a project I am currently working on and having a little trouble with. I know I am missing something critical, just can’t work out what.
I have been tasked to create some character models using Quidam and Zbrush and whatever else I have in my toolkit. Since I am fairly new to 3D, though not new to art, I am trying to pick up some good working habits.
I have created the character in Quidam, nude, and exported it as an .obj file, which I have imported into Zbrush. I have then used the model to extract mesh for the shirt and pants, which I have sculpted and textured. My plan then is to import the mesh back into quidam and use the texture that I have painted in Zbrush on the imported mesh.
I am coming unstuck on the texturing of the extracted mesh and I’ve spent the last few hours searching for information on it.
My question is… what am I missing? I have the mesh extracted, saved as a subtool, painted on the texture - I think that the UV map is what is missing because I can’t save the texture. I would really appreciate a step by step guide to getting a working texture onto an extracted mesh for export and use in another program.
When I use any of the UVP, UVC buttons and try to convert my colour to texture, my model disappears - I think because the texture assigned is transparent. And using UV tiles produces a mess of a texture. I will admit I don’t fully understand UV mapping so go ahead and make it as simple as possible 
