I am learning to use SketchUp Pro to define a scene and then import into Manga Studio EX4, that way I can use a single scene in multiple drawing, saving me a lot of time. (Actually, the real reason is that I am suck at drawing perspective.) So when I found that Manga Studio EX4 kept crashing whenever I use my stylus to draw something on another layer with a 3D object in it, I was desperate.
After wasted half an hour keep trying and trying, I eventually rebooted the machine, and found that the problem went away. And then I looked back and remembered that I have Sketchup Pro 7 running WHILE using Manga Studio EX4. Maybe both programs fighter for OpenGL access. Anyway, at least the problem seemed to go away after the reboot.
I also found that after I render the 3D object as a raster (and exist as "3DLT Rendering Folder") I can manipulate indivdual layer. This is important because I want to touch up the rendered 3D object so that they don't look so stiff.