How to Cut a Section Out of a Solid in FreeCAD

If you want to remove a rectangular section from an existing solid in FreeCAD, you can use a Part Box as the cutting object and perform a Boolean Cut. This works similarly to using a cube to make a hole, except the removed section can extend through the entire object.

Steps

1. Create a Part Box

   • Switch to the Part workbench.

   • Create a Box.

   • Position and size it where you want the material removed.

2. Make the Box intersect the solid

   • The Box must physically overlap the original solid.

   • It can extend beyond the solid if you want to cut all the way through.

3. Select the objects in the correct order

   • Select the original solid first.

   • Hold Ctrl and select the Box second.

4. Perform the Boolean Cut

   • Go to Part → Boolean → Cut.

The result is:

Original solid − Box = Cut solid

The Box acts as the cutting tool and is removed from the result.

Important

The selection order matters:

Solid first → Box second → Boolean Cut

This is different from Boolean Union, where selection order does not matter.

This method is useful for creating holes, slots, recesses, and other rectangular cuts without having to modify the original model's sketch.