Masking part of a 3D-object


I have a slightly curved bar, that represents the current speed of a vehicle. What I need to do is to cut off the bar so that it is only filled to the current speed indication, while keeping the same curved shape, so resizing vertically is not an option.
Can I mask that off somehow or use another object and hide the intersecting parts or use a completely different approach?



Ok, I think I searched for the wrong things.
The set_scissor() function of a NodePath seems to do what I need.
So I’m just posting this since someone who wants to do the same thing might find this helpful.