Sun — it only lights the Surface display.
SketchUp Free: import the STL (choose Meters). SketchUp Pro/Go: the KMZ keeps the terrain photo; DAE works too. Points: PLY or LAS for Scan Essentials / CloudCompare. Ground is the terrain surface; Structures are the scanned mesh above it (house, walls, trees, furniture). STL, DAE, KMZ and LAS are Z-up with north +Y; OBJ, GLB and PLY are Y-up like the viewer. Only PLY, OBJ and GLB keep vertex colours; the terrain photo travels with DAE, KMZ and the zip. Phone LiDAR resolves roughly 1–2 cm locally, so cells or photos finer than that only interpolate; the finest settings load the full-resolution data (tens of MB). Files are built in your browser, nothing is uploaded, and they contain no real-world coordinates.
Drop a .ply file on the page to view it locally — nothing is uploaded.
The Nav buttons act like dragging in that direction; hold to repeat. The URL holds the current view, so you can share it.