Recently, I ran into a problem where I needed to map the elevation of a polyline onto a DTM. Unfortunately, I couldn’t do this on the “terrain” point cloud because there were holes in places where “non-terrain” areas occurred.
I solved this problem in QGIS, where I imported the DTM generated in Pix4Dmatic, then imported the vector layer whose vertices I wanted to place at the DTM elevation, used the drape function, and re-imported the file into Pix4Dmatic.
But why can’t this be done more easily in a single software program?
Perhaps you could consider introducing a function to rasterize vector layers (polygons and volume outlines as well – not just polylines) not only to point clouds but also to DTM/DSM?