How do you create a circular or curved trace?
Two ways to do it, allow rounded corners during layout, or (usually easier IMO) laying out 90 degree corners and coming back with the 'Mitre' tool to apply the rounding.
Of course, these are all for single-radii curves; for complex curves you'll have to get creative...
Rounded corners in 'Route Manual':
The options here aren't documented [are they?] but you want 'Trace Bend': the selected option creates a rounded corner on a 45° bend, and the one to it's right creates a rounded corner on a 90° bend. The 'Corner Radius' field specifies the maximum allowed radius of the bend (it will use less if it can).
Mitre tool:
Mitre works in the same way but is applied to a trace that's already laid out. Setting the radius to '0' sometimes lets you go back to a 90° corner (but seemingly only when it's not critical!)
