Removing artefacts from photogrammetry model

Hello

Im very new to blender. I’m trying to create a base for photogrammetry model for 3d printing. It is part of a building facade. I cant get the desired result due to unwanted artefacts on the edges. Is there a way to eliminate these artefacts?

Bad geometry issue at beveled parts.

Firstly, make sure you turned on “Auto Smooth” if shade smooth is applied.
Select the object (Object data properties at right menu / normals / auto smooth)

Besides. mostly Blender will do a good job at recalculating the normals. Go to edit mode, select all by pressing “A” and hit “shift+n”. So, this will have Blender recalculate normals.

If it does not work, then you have to check if correct bevel methods are applied.

To bevel specific edges;

  1. In 3D viewport ; Select object, hit “CTRL + A”, choose “All Transforms”.

  2. Go to edit menu, hit “2” (to get edge select tool) and choose the edge that you want to add bevel; then hit "CTRL+B’ and move mouse cursor down to see edge is being applied, at the same time use mouse middle wheel to add edges (few pcs will be fine).

Try above and see if one of these work…