Saturday, February 2, 2013

SketchUp 8 + STL Files for 3D Printing

Galata Tower STL in SU8
EDUtutorial :: I have an older version of SketchUp 8, but I really wanted to try the new .stl plugin announced on SketchUp's official blog.

STL files are what you would use in 3D printing, and so having the ability to import STL files into SketchUp, or convert models you've made in SketchUp into STL files, allows you to add SketchUp into your 3D printing workflow. 

If you have the latest version of SketchUp 8, all you have to do is follow the easy instructions on SketchUp's blog to install the new plugin. You simply go to Window>Preferences>Extensions and then click on Install Extensions... Then you navigate to where you downloaded your .rbz file and go on from there.

Since I have an older version of SketchUp 8, I have no such button called Install Extensions. So what I did instead was what you normally do with all ruby scripts -- drop them right into SketchUp's plugin folder manually.

Here's the steps...
  1. I opened up my Plugins folder by going to Program Files>Google>Google SketchUp8>Plugins.
  2.  Then alongside that folder, I opened up the folder I downloaded the .zip file for the STL plugin into (download here).
  3. You should have a .zip folder titled, sketchup-stl-master. Inside it should be a normal folder also titled sketchup-stl-master. Inside that you will have 2 folders and several other files. The one you want to open is src (images below). 
  4. Take the folder and .rb file you see in there and drag it over into your Plugin in folder you already opened. 
  5. After this, simply start up SketchUp, check under file to see if you have STL options included, and begin enjoying your new STL plugin. 

Here's where your SketchUp plugins should be -- Program Files>Google>Google SketchUp8>Plugins. This is where you drag new ruby scripts (.rb files) and any accompanying folders required.

Inside your downloaded .zip folder, these are the two files you need to select and drag over to your SketchUp Plugin folder. Then, start up SketchUp and check under "File" to see if you now have STL file options.
I've been able to import simple models (such as GalataTower-Istanbul) into SketchUp using this plugin, but it is slow, and there is a process the plugin seems to be doing called "repairing geometry" which leaves the model's surfaces with all sorts of gaps and irregularities.

An imported STL file from Thingiverse -- Galata Tower, Istanbul. Upon closer inspection, there are holes in the geometry, random lines and other irregularities that don't show up in FreeCAD.
Other, more complex models, (like this SpaceX Dragon capsule) don't open at all. 

This doesn't happen in FreeCAD.  Could this be the result of not properly installing the script? I don't know.  SketchUp doesn't do well with any complex, imported geometry, say from ZBrush or 3DS -- at least not on my computer, so maybe that is the issue.

The same SpaceX Dragon capsule that wouldn't open in SketchUp, opened in FreeCAD in seconds, with perfect features. Maybe I need to start learning FreeCAD.

What I can do, however, is export models I make in SketchUp as STL files and open them in FreeCAD. And I think that is the most important feature gained out of this. If I were using SketchUp to make models for printing, this is how I would do it --- by exporting them as STL files. Since this can be done easily and successfully with the new STL export feature made possible by the STL plugin, perhaps for now it doesn't matter that I can't import complex models made in other programs.

While importing STL files didn't work well, exporting them did. If it opens on FreeCAD (top) without incident, I'm hoping that it will be able to print just as easily.

Of course, the next step is actually taking an STL file exported from SketchUp, and seeing if it can be printed, or used in other manufacturing processes such as laser cutting or CNC milling. If you get stuck on any of these steps, feel free to contact us. Also, if we're making obvious mistakes or you think there are better ways to do any of this, also feel free to contact us