I have a model city created from the top faces of buildings extruded downwards through a plane. enter image description here

However, I would like to cut these extruded buildings and have them terminate at either the top or bottom face of the "base". Is there some was I can either delete the object past the face or split the mesh at a face to make it easy to delete all the extra material underneath the base? Thanks!

  • $\begingroup$ Is the city one object or several objects? And do you need the bottom of a building to be closed by a face or doesn't matter if it's open? $\endgroup$ Commented Jul 30, 2021 at 6:27
  • $\begingroup$ the buildings are all a single object, and the plane is another. I need it closed, I figured I could join the city to the base into one object that would allow it to be closed. $\endgroup$ Commented Jul 31, 2021 at 2:35

1 Answer 1


I think you can easily join all buildings together into one object with Alt+J, then use Bisect that is next to knife and cut it along the plane very easily... After that select your city, go to edit, press A to select all vertices, right click it and select Separate by Loose parts... All your buildings will be cut and as individual objects

You can do this or either use boolean to use plane as cutter to divide objects into two and delete bottom part

  • $\begingroup$ Just use 'Clear Inner' or 'Clear Outer' on the bottom-left Bisect setting dialog. No need to separate and delete the mesh afterwards. $\endgroup$
    – John Eason
    Commented Jul 30, 2021 at 9:03
  • $\begingroup$ Is there a way to bisect along a selected plane? Id like it to be exact and not draw. Can you please explain how to select a face to use for boolean in order to cut? I seem to only be able to select the whole object. Thanks! $\endgroup$ Commented Jul 31, 2021 at 2:44
  • $\begingroup$ As far as I know you can enter values in the bisect tool options... but I'm not at a computer with Blender this weekend to test it. $\endgroup$ Commented Jul 31, 2021 at 13:57

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