Some years ago I put together a collection of Matlab files for plotting
direction fields and numerically generated solutions of systems of ODEs
in 1, 2, and 3 dimensions. I have used it for teaching both
undergraduate and graduate courses. Along with the *.m and *.mat files
you will find Instructions.pdf which explains features and use of the
commands. Note that it has been some years since I last updated
these. It is possible that some features of Matlab have changed,
which would require modification.