How do you make those custom signs like the one that says 'Shadow' on the rocks? Do you have to use Sketch Up?

This is the best wingrider i've ever seen.

How do you make those custom signs like the one that says 'Shadow' on the rocks? Do you have to use Sketch Up?

Yeah I used sketchup with the rct3 plugins, then imported it.
Here are some great tutorials (and the sketchup plugins) if you're interested in making your own:
http://pbjstudio.weebly.com/tutorials.html

I made one a couple of hours ago. Turned out great!