CUBIT is a software tool for solid modeling and mesh generation for finite element analysis developed by Sandia National Lab. You can read all about its features here: https://cubit.sandia.gov .
If you are working on a mac, download the following disk image and install it. If you don't have a mac, run the version on the server.
cubit-14.0-mac32.dmg CUBIT was originally developed as a command line program without its current graphical user interface (GUI). Commands can still be entered manually in the command window, and many times it's faster to do this rather than click on the GUI. If you will using CUBIT a lot, it is worth it to learn a few basic commands here. The CUBIT manual is a very good resource. CUBIT commands can be written and saved in a text .jou journal file and used to generate the geometry/mesh using the playback command. To get started, use the GUI to create your geometry and mesh, then look in the history window to see the commands associated with each step. Copy the commands to a journal file and modify them as needed. Do this enough times, you will learn the basic commands and won't need to use the GUI. You can also type help [command] in the command window to get the syntax structure of the command.
The advantage of the journal file is that you can “playback” the file to automatically generate the geometry and mesh again. Moreover, you can define variables in the journal file (e.g. for the radius of the cylinder) and use them to create your geometry and mesh. This powerful feature allows you to parametrically alter your mesh. When developing a mesh, strive to parametrize as much as you can the dimensions and meshing intervals/size so that these can be modified rapidly for a mesh convergence and parametric study. Also, name your volumes, surfaces, curves, and points (see bovine_cornea.jou for example). That way you don't have remember the number ID of a geometry when referencing it in subsequent steps. The number ID which will change if you change the steps prior to creating the geometry.
Remember to merge your geometries before meshing.
Finally after you create your mesh, use the utilities in CUBIT to interrogate the quality of your mesh. Remove distorted elements (small angles and elongated aspect ratios).
Here are a few examples of journal files that can be played back using CUBIT 14. You can open them with any text editor
Cube
Bar
Symmetric model of ring
Circular Plate
This tube
Quarter model of the corneal-scleral shell
Bovine cornea. The script imports holder.sat and this file must be in the run directory
Mouse sclera
Spherical indenter
Edge crack in a strip
Edge crack