Compared to other free 3D-CAD programs, the Creo Direct Express is a well developed alternative thanks to its semi parametric functionality and import functions. Its a direct modeler without tree history, but it still got some means of measurements as the sketching and extrudes all have the current length displayed.
Creo Direct Express supports import of formats such as IGES and STEP, making it a very useful tool for the engineer or hobbyist. Export formats are however limited to the polygon formats STL and WRML, when not saving in the native format pk2.
When prices for a standard commercial CAD tools license such as SolidWorks starts at 6500€, the free or cheap alternatives are needed when basic geometry operations is the goal. Most geometries can be achieved with pull and cut extrudes.
A short intro.