Multiscale should defintely be disabled on road projects, in my experience. My opinion is that if the points can’t be built with confidence, they shouldn’t be built at all. I would much rather see the gaps in areas with low visual content and be able to identify them, as opposed to having to manually clean up noise around points that are low confidence anyways. The best luck I’ve had with curbs are using the flight settings I listed above (“low & slow”), and also high overlap for the sole reason that I want to increase my number of matches to 4 or 5, as Beata said. Also, don’t even bother with all of this if you’re doing an as-built on a brand new road. Fresh asphalt is a no-go.
There’s a lot of areas where drones, photogrammetry & pix4d really come in handy and provide a benefit to us and our clients. Design surveys in dense urban areas are one of those if you’re talking 2D, but the 3D data can be very hit and miss. I’d guess that ~75% of the time, we only use the drone to produce an orthophoto in those situations and just have the point cloud ready to extract features that may have been missed in by the field crew, like fire hydrants or powerpoles. They also serve as a great check/red flag for bad field shots, and the orthos are very low-effort to produce, as you know. We tend to save the digitizing & surface building drone uses for projects where we know it’s effective and efficient, like rural topos, landfill calcs and grading analysis.