This tip from the Augi Forums:
Here is one way to pull your Revit model into Sketchup:
1. While in a 3D view turn the “Section Box” on found in view properties and compress the section box to just the area you want to study in Sketchup. This may be the whole model or just a piece an entry alcove, one exterior elevation, etc. Depending on the speed of your computer and the size of your Revit model, you may want to narrow the scope of the exported model in order to decrease file size.
2. File – Export – CAD formats. In the “Export Options”, under “Solids” choose “Export as ACIS solids”. This will export Revit objects/elements as components so that they don't get too sticky when working in Sketchup.
3. Once your export is saved, open Sketchup and “import” the dwg. The file will import with DWG layers as Sketchup layers, separating your glazing from your doors, etc.
4. Change your layer setting in Sketchup to “color by layer”. This gives you universal control over the color/material of all of your glazing, doors, etc. Change the color/transparency of each layer to your liking.
This isn’t a perfect process but I find it works well to take advantage of the more design-friendly interface of Sketchup and to produce quick color images for clients.