The DSM is generated from the filtered point cloud. The filtered point cloud is generated from the densified point cloud that is generated based on the Automatic Tie points. Areas where the DSM has big triangles or is badly reconstructed are areas where the densified and filtered point cloud have bad, few or no information at all.
In order to improve the DSM:
- Add some Manual Tie Points and Reoptimize: How to import and mark Manual Tie Points (MTPs)
- Process again the project using Process > Options... > Point Cloud Densification > Point density: High(slow).
- Fly again with a higher overlap.