Take a detailed model and make it suitable for 3D printing? I have a model I would like to print, specifically it is a free-for-personal-use model of a car, complete with interior.

I would like to print it, but it is unprintable. I have tried to fix it in netfabb, which works OK. But now I realised I have another problem - the inside of the car is hollow, and has a full interior. I just want the shell of the car and a solid block (complete with opaque 'windows').

How would I take a detailed model and somehow extract a solid 3D printable model from it?
I would recommend "The Maker's Muse" youtube video channel.

In particular this video Fixing impossible STL's with Meshmixer 3.1.118 BETA might solve your problem.

Few other videos which might help:


How to make Engineering Assemblies 3D Printable using Meshmixer
Add smoothness to your meshes using remeshing! 3D 101
A Detailed look at Processes and Profiles in Simplify3D
Tidy up your prints with the Modifi3D
How to Print Bigger Things - 3D Printing 101