Under Global Switches->Materials there is a checkbox titled Glossy Effects. What are they?
Re: “Glossy Effects”? - What is it?
glossy effects are blurry reflections. basically if your reflection glossiness is less than 1, then its a glossy effect.
because glossy effects are slow, the option is there to let you turn them off for test renders.
Re: “Glossy Effects”? - What is it?
Ah. Thanks.
…hm… but that checkbox is unticked by default… so if I use materials with less glossiness I should tick that then, right?
Re: “Glossy Effects”? - What is it?
well, i only have access to vray for 3dsmax from this machine, but assuming the settings work the same on sketchup, then yes.
really it should be on by default 
maybe it depends what preset you load.