For materials that vray freeze trying loading them, you must change them. For those that load slow, you can reduct the resolution and dpi of textures (both of diffuse, bump and displacement). In the progress you will see which materials load fast, which slow, other don't load. Materials - Look your vray progress window. Check your geometry with solid ispector, solid solver or manually.
Improper geometry - Sometimes vray can't triangulate the surface. The problem can be by some things: improper geometry in one or more of your components, improper materials or the resolution and your configuration. Im starting to think there is something really wrong with vray and/or sketchup. Yes a lot of translucent material but with minumum quality settings and my computer is not really that bad (i5 3570 3.4). I even removed the lights from the model and still it didnt make a difference. Yes i have 2 vray sphere lights inside the model, but thats not the problem. No bumps, not reflection, no anything at all. Simply red, orange and yellow materials with the translucent value to 50. My whole model is translucent and it doesnt matter what i do, vray dont have the "strenght" to render em. The problem in my case seem to be translucent materials. Im talking about an entire day and the render process not even in half way. But then the irradiance maps takes forever. (ridiculous i know) then the light cache this time loaded fast. At first the light cache in my model took ages, then i gave up and i directly lowered the light cache subs to 300 or something like that. Not only with the light cache but with the whole rendering process. James, how it was? i post here because i have a similar problem and i cant figure it out. If you would like to see my settings, just let me know which ones you would like to see and i will provide it. This is a very confusing issue for me, and any help would be GREATLY appreciated. When I turn materials back on, again, it struggles though building the light cache. When I activate the override material mode, with ceiling on, the render whips right through it, and no issue (please view attachment). I even removed ALL furnishings and polygon-heavy elements until my model was only 7mb, but still, with the ceiling on, V-ray could NOT get past building the light cache. My model is only 115mb, not that big considering I have rendered much bigger models in much less time. But, obviously not my intention to show a ceiling-less room! So I had the idea to remove the ceiling (upper floor) to let the sun in, and this sped up the rendering process to almost no time at all. With all of my V-ray settings at sub-default quality, the rendering process takes hours and hours to even build the light cache. I created a model of a townhome complex, and have furnished one single floor of one unit with components and materials I have never had issues with before. I have been struggling with a render and cannot for the life of me figure out why.