You will then see the surface dialog
or by right-clicking on the Surfaces object in the Objects window and choosing New Surface...
or from the tool bar
A Surface object can be made from the menu
This is done by making a surface object, which references solid objects and then selecting the surface from the machining operation.
Any machining operation can be applied to a 3D surface.For example, here is a standard pocket operation, with its toolpath being applied to a sphere.
By default, all the solids in the drawing will be selected. If you only want some of your solids selected, then click the "Pick" button and select the solids you want.
If you don't want to see the solids any more, you can select them, then untick the "visible" property in the Properties window.
Click "OK" to confirm your choices and create the surface operation.
Now, edit the operation that you want to be attached to the surface and choose the new surface from the "surface" drop-down.
When you do "Post Process", you will see the pocket toolpath has been attached to the sphere.
It uses the tool shape to correctly drop the tool down on to the surface; a ball nose tool will give different toolpath compared to a flat end slot cutter.
For operations with thousands of moves or complicated surfaces, it is worth opening the Print window ( from the Window menu ).