Hey @Mike_K,
The problem with a TIN is the resolution isn’t the same. A DSM uses the GSD (usually around 3.2cm for me) whereas a TIN uses the Grid of Points (which I can only get down to .7m grid spacing) resulting in a lower resolution surface.
Here’s a rough screenshot of the difference I can see.
For anyone facing the same issue, here is the workflow I have come up with for the time being.
- Calibrate, Densify, Generate DSM and Ortho in Pix4D Matic
- Terrain Filter in Pix4D Survey
- Export Filtered Point Cloud from Pix4D Survey
- Convert las 1.4 file to 1.2 with las2las.exe
- Import Photos into Pix4D Mapper and run step 1
- Open las 1.2 file in Pix4D Mapper
- Generate DSM from imported file
- Create XYZ tiles in QGIS from Orthomosaic
- Draw Polygons in Pix4D Survey
- Export Polygons as .shp file
- Use Split Vector Layer (QGIS) for Polygons: Vector > Data Management Tools > Split Vector Layer…
- Import DSM and .shp files into QGIS
- Extract Rasters from mask layer