Surface Gages

Have you heard of surface gages, but just don't know what they do or are for? Well, for one thing, they're used during the animation process. I personally have never used one(yet), and I had the same question a while ago. After some research, I found a nice article by Anthony Scott about them that explains what they are for and how they are used. You can buy a more professional one or make one yourself, I'd stick to making one yourself until you think you'll need it. Anyways, the link to the article is below as well as a link to a search on Ebay for them. You can find some good deals from time to time on there, just keep checking back with it.

The Importance of Using Gages by Anthony Scott
Ebay Surface Gauge Search
Ebay Surface Gage Search (different spelling variation may give different results)