# Problem with Boolean Difference Overhang

I continue to be challenged with boolean difference. This time I have used the 3D Print add-on. It is telling me that there is an Overhang Face. In edit mode I select "Overhang Face: 1". It shows me the face and I don't understand why it is overhanging.

Note that I have already attempted to clean things up "Remove By Distance" and have done other cleanup.

Here is file

• Thanks. This is not an easy problem to visualize but will give it a try. – Dale Dec 21 '20 at 3:32

I understand it can take awhile to wrap your head around it. I create all my 3D printed models using Blender 2.91. The Boolean operator has been greatly improved using the exact and self options (Although the Fast option will work with this model just as well)

1st) The overhang is just the bottom face. Should print just fine not sure if your printer will require supports for the hole though.

2nd) Animation of doing Boolean - Difference with your object.

3rd) Animation of overhang location and how to find it.

4th) If you want to display the hole during edit mode you have to enable it or apply the modifier)

5th) Exported to slicer note: not sure if your printer will require supports for the hole or not.

• Wow, thank you for the super detailed answer to my question. This is awesome! I will see if I can successfully recreate what you have done:) – Dale Dec 22 '20 at 5:56
• @Dale anytime the users in this group have helped me a lot so I try and pass it along when I can. And if you decide to do more CAD like things using Blender this channel will help out A LOT. youtube.com/c/MakerTales/videos – Rick T Dec 22 '20 at 6:49
• Hi Rick, I was initially stuck when following your steps. The export had the calendar included. After a bit of web research, I went back and clicked "Selection Only" during the export. This worked! Is this the right way to go about it? And thanks for the pointer to the videos. – Dale Dec 22 '20 at 14:28
• @Dale the only right way is what works best for your work flow. For me, I just select the object I want to export as an STL and use the 3D-print tab. i.imgur.com/cVKMoEu.png – Rick T Dec 22 '20 at 22:16