I just installed an arch trim for a half round living room window. Wood is 3/4" oak. Overall dimensions are 21" tall x 42" wide. I had to machine the arch in two halves as my Shop table is 24 x 32. The extrude along centerline was the perfect modeling tool for this job. I did a rough cut with a 1/2" end mill and finishing cut with a 1/4" tapered round end mill.