I have extracted a 3d satellite image of a city to a .rdc file using renderdoc and imported it into Blender then selected ALL and joined to a single mesh (ctrl J). I have 'cleaned' it up in edit mode using the lasso tool and then delete vertices. There are still many small objects which are 'floating in space' (not attached to the main object (see image below with one such selected with the lasso). Is it possible to select ONLY those small objects for deletion? I have manually removed many but there are still some which I cannot 'isolate' and 'lasso' as they are too close to the main object to be able to select with the lasso without also selecting part of the main objectn object. Maybe this could be done BEFORE joining all meshes?
If you know you have only one big main object and a lot of floating ones, you can separate by loose parts.
- select your main object and go into edit mode
- select all geometry
- right-click and
Separate > By Loose Parts
- go back to object mode
- select your main object, invert selection and delete