This is a test in making a 3D model from a DTM for a 5km-square area. I downsampled the model to be less bulky. I’ll see about applying a smoothing filter so that the polygons aren’t so jagged, but decimation also took care of some of that.
I used ArcMap to load a DTM for Gatineau Park, focused in on the area of the Mackenzie King Estate, and created a TIN. I then opened this in ArcScene to export it as a .WRL, which could be opened in MeshLab and saved in a variety of formats. I did the downsampling in AutoDesk Recap Photo.