Firstly I must say I’m very disappointed with Vray 3. Here is a direct comparison between the two versions. The first one is made with sketchup 2016 and vray 2, and the second one is made with sketchup 2017 and vray 3. Dont look at the quality of the render itself . It is just a test.
What I did:
Created my model and rendering with su2016-Vray2, saved the model and opened it with su2017 that has vray3. Had only to add transparency manually to transparent materials (glass). All the rest of the settings I did not touch. The resulting render is far worse than the one made with vray2. Look at the detail of the keyboard!!
Can somebody explain to me what happened and how can I get at least the same looking render I did with vray 2?
Eventually I did experiment with the settings and lighting a bit with the vray 3 and still was not able to get the result I did with vray 2.