In the above image, I have three separate bodies. One is a surface body, which is the body with the ocean decal applied to it. The other two are solid bodies (the red cylinder and the translucent solid surrounding it). Let’s pretend, if you will, that this ocean wave is roaring to rip the top of this cylinder off with the topological geometry seen at the top of the surface. As you can see in the above screenshot of the part, the surface is pretty bumpy. Imagine forming the eventual top face of the cylinder with Cut Extrude features. It’d be pretty difficult to do that, right?
The reason I chose an ocean wave for this example is because it’s easy for all of us to visualize an ocean wave. Picture the very top ‘surface’ of an ocean wave. It’s very bumpy and curvy, isn’t it? What if we wanted that same bumpiness and curvature to top off something like a solid cylinder?
As you can see, ‘Cut With Surface‘ is a command that makes a cut to the solid model by removing material from that model with a surface body. If we use this feature, all we have to do is select: a) our surface body to cut with, and b) our solid to cut.
You’ll see that ‘Body-Move/Copy1′ inhabits the ‘Surface Cut Parameters’ box. This is the name of my surface body selection because the body automatically took the name of the last feature used to modify it. The same applies for the cylindrical body I selected under ‘Feature Scope’. You’ll also notice that my mouse is hovering over an arrow in the viewport. Clicking this arrow allows you to flip the direction of the cut, if needed. Right now, it’s pointing in the intended direction. Therefore, I will leave it alone. I am now ready to execute the command, so I’ll click the green checkmark.
As you can see, the top surface, displayed in grey, has changed. Its shape is now dictated by the topological geometry of the surface we used to cut it. Post-cut, I simply hid the surface body (as well as the solid body formerly surrounding the cylinder). I’m hovering over the feature which built the surface to display its outline, which might give you an even clearer idea of what the command actually did.