Design draftsman Joel Sanders sent in a trick for getting radial AutoCAD dimensions to point to the inside of smaller arcs, circles, or fillets.
"As far back as I can remember, AutoCAD radial dimensions have had a penchant to always follow the outside geometry. When asked by a colleague the other day about this problem, I came up with an obvious solution. In the newer versions of AutoCAD (2007 and up), whenever a radial dimension is placed and the dimension arrow swung around so that it is on the opposite side of the geometry, a pesky extension line appears and any radial movement of the dimension swings along that outside arc. By highlighting the dimension after it has been placed, you can use the Properties dialog box and turn the extension line off. Don’t worry if the dimension moves back to the arc contour — just grip it and swing it around, and you will see the arrow point to the inside of the arc when you get to the open end of the geometry."
Notes from Cadalyst Tip Reviewer Brian Benton: There are a tremendous number of settings for AutoCAD dimensions. Finding the right combination for your use can be difficult. Add to that the complicating factor of unusual situations, and your standard styles can be thrown out of whack. Individual dimension objects can always be overridden by using the Properties palette to make changes. Don’t be afraid to make more styles for these situations, either.