Ooze test piece

This is a test object for extrusion based systems that is quick to print and will exhibit a lot of ooze unless countermeasures are taken.

I\'ve been working on anti-ooze for my Bowden based extrusion system (which has a lot of oozing if you don\'t do anything against it). Together with Nophead we\'ve had particularly good results:
http://hydraraptor.blogspot.com/2009/11/hacking-with-erik.html

The latest version of my 3D-to-5D.php software solution checks whether a pull back is necessary. Segments that are very close to each other will not result in a pull back. If it\'s further apart, it has time to ooze more. Also, I don\'t want it to add too much to the build times.

Other references:
- Adrian\'s response when also trying pullback (again):
http://blog.reprap.org/2009/11/end-to-ooze-ii.html
- Nophead\'s RepRap blog post:
http://blog.reprap.org/2009/11/end-to-ooze-and-support-material-found.html
- Extruder valve
http://blog.reprap.org/2008/08/extruder-valve.html