STLViewer is a free cross-platform viewer of STL files.
Icons are partly retrieved from the Font Awesome icon set.
Clone the git repository:
git clone firstname.lastname@example.org:cravesoft/stlviewer.git
For Ubuntu, simply enter the following command that will install all necessary packages:
sudo apt-get install libqt4-dev libqt4-opengl-dev qt4-qmake
qmake && make
This will generate an executable called