To fix sharp edges in building 3D models, use edge smoothing tools, add bevels, or apply subdivisions to soften hard lines.
Smoothing (e.g., Blender’s Subdivision Surface) adds polygons to round edges, while bevels create small, realistic chamfers—ideal for materials like concrete or wood. For low-poly models, use bevel weights or normal maps to avoid excess polygons.
For real-time use (games/AR), start with subtle bevels—they boost realism without hurting performance. For renders, combine smoothing with material roughness to make edges look natural.