If I draw a circle , what are the dimensions of inside , outside and path 50mm
That would depend on the cutter diameter you use and whether you are on the toolpath or inside or outside the toolpath. It’s math. When you select your bit in easel, the circle will correspond to that bit diameter on the graph. Draw your 50 mm circle and then change bits. Close the detail bit box if it is open to see the changes as you select different bits.
Inside = 50mm - 2 * bit_diameter
Path = 50mm - bit_diameter