Wednesday, September 9, 2009

“It cuts though a tin can then slices a tomato!”

While I’m waiting to make repairs/ improvements to the belts, I thought I might take a moment to talk about slicing stl files. I did some Google searches and found several software packages that could slice my files but they were way out of my price range. I guess if I was going into business as a rapid prototyper I could rationalize the expense, but for my own personal/hobby use the prices were prohibitive. There were some budget (free) options (like slicing with PovRay) but I couldn't get them to work and didn’t understand the scripting involved. Then I found the Project 1 utility at the Yahoo DIY 3D Printing and Fabrication group. Thank you Paulo, for graciously making your slicer available to the groups’ members.

The utility is easy to use and doesn’t require any additional programming skills. Simply open your stl file in the slicer, pick a printer, set the slice thickness, and hit print. You can scale and rotate the model as well as shift the print position to center it on the page. One thing to note is that the measurements are in metric. You need to convert your stl to millimeters if you want it to print at the size you are expecting. My other observation is that the mesh must be clean and watertight. From what I understand, that’s not unusual for 3D printing. It’s probably also the reason the other software was so expensive. Unfortunately, my meshes are typically neither clean nor watertight (I really need to learn better 3D modeling skills).

I am modeling in Silo and using MeshLab to check and repair my meshes. Some are so hopelessly messed up that I’ll have to go back and start over. (There is also a slice feature in MeshLab but it outputs svg outlines and I need silhouettes.) MeshLab is open source and can be found at Sourceforge ( Silo is available from Nevercenter ( for a modest $99 ($159 for the pro version). They have a 30 day trial if you want to check it out and a very friendly and helpful users community. I'm still very much a Noob with Silo but I found it to be much more intuitive than Blender and WAY less expensive than Rhino, Lightwave, or any of the CAD packages (Hell, even Google Sketch Up is like $495 if you want to be able to output anything other than their own format). Again, if this wasn't a hobby (and I wasn't incorrigibly cheap), expese wouldn't be such a big issue.

Anyway, now I need to make my repairs and whip up some test files.

1 comment:

  1. Hi John! I'm new on the DIY 3D printing group, my sn is quazga on there. I'm just going through the files area and stuff and came across your blog. And I just wanted to say that you can very easily convert from Sketchup collada to any of the formats Meshlab exports. It probably wasn't available at the time you wrote this, but Meshlab does import collada DAE files very well at this time. Also, you can use accutrans 3D, free or pay $20 US if want, to verify the water-tightness of STL files. =)