Reduce file size and choose ideal file type I have several stl files that are rather big (70 MB and more) and messy(surface scans that have been converted to stls, holes and uneven surfaces) and would like to understand better the process of reducing the filetypes and choosing the ideal file type for the best size/quality ratio because I would like to make them available online/download (Blend4web). 

I know about the decimate modifier but don't have a complete understanding of the workflow (so I can tweak and optimize each step) to choose the right filetypes, reduce the polygons, smooth the surfaces (keep the overall shape but remove holes) and export to the ideal format. If there are scripts that automate this I would like to know about them.  

If anybody would be aware of a good tutorial or script that does this please let me know.

Thanks for your help.
Decimation will reduce amount of geometry but also can severly affect its quality. Process of retopology would provide decent results but it is for the most part manual, time consuming and can get boring. (On the bright side - at least it is not extremely difficult)

Retopology would give you full control of how the model will end up looking, something automatic solutions wont be able to deliver.