Thursday, March 7, 2013

Frustration...and Progress

The goal this week was for students to print objects they designed, or at least found online and wanted to see in 3 dimensions. One thing we have learned is that translating a 3-dimensional model in the computer into 2-dimensional cross sections that can be used to print an object is extraordinarily hard.

The students have been getting really good with SketchUp. Meanwhile, I have found a plugin that translates .skp files from SketchUp into .stl files that can be manipulated in FreeSteel to create .png cross sections. Unfortunately our only viable FreeSteel installation is on an Windows XP machine, and we have to run the the cross section program, slice, in DOS. Slice works wonderfully sometimes; that is how we created the skull. Other times it gives a variety of errors. With Fedor's object, it ran out of virtual memory, with Yifu's it had an internal error due to cross points too close, and for other students it tells us the triangles are too big.

When slicer works, we get .png files that we have to create negatives for and sometimes re-size in xnconvert. Then we have a program what we run from command line on the Mac (using Mono as it is compiled for use in the Microsoft .Net framework) that turns the .png files into a slide show. Harry and I worked together to try to print a small sword. There will be a picture up tomorrow but it was less than fully successful.

With the likelihood of printing our own objects dwindling, we have refocused on creating some objects from the online library of the folds at NANO-CEMMS who designed our printer. Fedor and Nikita created a lego block from one of these files, and the other students will be printing from this library tomorrow.

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