OpenSCAD is a software for creating solid 3D CAD objects. It is free software and available for Linux/UNIX, MS Windows and Mac OS X.
OpenSCAD is a free software which concentrates on the CAD aspects of any solid design rather the artistic aspect of the design like being done by Blender. This is the go-to application for you 3D modelling needs such as machine parts, automobile parts etc.
By not being an interactive modeller, OpenSCAD gives you freedom to control the modelling process as a designer. It uses a script file describing the object and renders 3D design based on the script file. You can easily change any step of the design process.
OpenSCAD is also able to read Autocad DXF files along with popular STL and OFF file formats.
OpenSCAD depends on number of free softwares such as Qt for interface, CGAL, OpenCSG, boost, eigen and glew. OpenSCAD is a regular accepted project in Google Summer of Code.
How to Install OpenSCAD in Ubuntu/Linux
To install OpenSCAD using PPA including Ubuntu 16.04 LTS Xenial Xerus, run below commands from terminal:
sudo add-apt-repository ppa:openscad/releases sudo apt-get update sudo apt-get install openscad
After installation, you can find it under Application menu Or, search in Dash.
Here is a screenshot of OpenSCAD running. Pic credit: OpenSCAD
You can also take a look at the entire gallery of examples here.