I have a question about materials that come from the paint bucket.
When you try to select glass or metal what you get is something that is very unconvincing.
It’s a gray pebble or a gradient or an otherwise non-metal looking fill pattern.
When I go to the Sketchup Warehouse, however, I can down load sinks & faucets that look like the real deal.
How do you create the realistic metal finishes that I see on those warehouse gizmos?
Is there a plugin that does this or is it done in a different software?
Yes as @MikeWayzovski said you need to check to see if they have used materials or textures that have photo or rendered textures applied.
Either they have used a photograph from a real sink or they have rendered the model elsewhere before going back to re-apply those textures in SketchUp.
There are many ways to texture a model, from UV mapping plugins, using the native tools, or a bunch of other plugins (that I don’t know about but I am sure exist).
The method you use depends on your source material. Certain methods require you to have a 3rd party image editor (GIMP is free if you don’t have access to Photoshop) in order to prepare the image files, crop them etc.