Please excel and speed up the process of bringing a dedicated 2D radius and chamfer tool to SketchUp.
There are a few extensions for that.
Round corner is free and Bevel and Fredo corner are payed ones..
2D? Are you sure?
2D extend, fillet, chamfer
Radius Tool
Simply use the arc tool correctly, why do you need another tool.
A 3 segment arc will create a chamfer.
