Blender
Crazy complicated 3D editor...
import
- file, import, import STL in top right corner
- zoom way out, object might be big
decimate
To reduce resolution and therefor file size:
- select object (orange frame should show)
- object modifiers (wrench on button bar in right panel)
- add modifier, under generate, decimate
- down to ~100 000 says Tony Buser's person scan process