3D

3D Warehouse contains millions of models created in SketchUp, the world's most popular 3D modeling and design application.
The Autodesk 123D community is a place to design, create and share anything. No matter your technical skills and experience, you will always have a place to get the latest tools and information to support your adventures in 3D printing.
Curated kid-friendly 3D design resources on the web.
A web app from MakerBot that allows you a little freedom to customize different objects. Customizer is the easiest way to take great 3D printable designs and make them your own. Make your OpenSCAD designs infinitely more valuable by empowering the community to customize them. Also good for beginners!
OpenSCAD is a software for creating solid 3D CAD models. It is free software and available for Linux/UNIX, Windows and Mac OS X. Unlike most free software for creating 3D models (such as Blender) it does not focus on the artistic aspects of 3D modelling but instead on the CAD aspects. Thus it might be the application you are looking for when you are planning to create 3D models of machine parts but pretty sure is not what you are looking for when you are more interested in creating computer-animated movies.
Project Shapeshifter is a free technology preview by Autodesk. It provides an easy way to create complex 3D Printable models in your web browser. With a simple tweak of sliders, you can control the object's shape and select a 3D pattern that wraps around it.
There’s a reason SketchUp is synonymous with friendly and forgiving 3D modeling software: they don’t sacrifice usability for the sake of functionality. Start by drawing lines and shapes. Push and pull surfaces to turn them into 3D forms. Stretch, copy, rotate and paint to make anything you like.
Tinkercad is an easy, browser-based 3D design and modeling tool for all. Tinkercad is also your perfect 3d printing companion – it allows you to imagine anything, and then design it in minutes! Tinkercad is part of the 123D family of free apps.