3D printing from Sketchup
I have been using Sketchup for a few years now, and I have always found it to be the fastest and most efficient tool for producing simple 3D models. What it lacks in complex features found in other modeling platforms such as Rhinoceros 3D and SolidWorks, it makes up for in speed and ease of use. Furthermore, the program has access to a massive free 3D warehouse where users can download a plethora of fully realized models. For a while now, I have been thinking about teaching a workshop here at the VFL on basic Sketchup techniques and the process of tuning the model into a 3D print. I had never actually attempted to Print form a Sketchup model myself, so I decided it might be a good idea to try it here at the VFL. The Model I decided I would use a model of the Guggenheim here in New York for my first attempt. There are a number of fully realized models for download in the Sketchup Warehouse, and I figured that the cantilevered balconies would provide an interesting challenge for the 3D printers. Once the model had been loaded into Sketchup, I went through a simple process of removing some of the finer details that wold not show up in the final print. Here is the model that I ended up with:
Converting to STL In order to push the model to the 3D printers, you first have to convert the native Sketchup .skp Format to a .stl file format. There are a number of ways to do this, but I decided to start out by using a free plugin called CADspan. one of the nice things about CADspan is that it comes with a built in tool that quickly lets you see if all of the faces of your model are oriented the right way. This is a critical step in making a watertight solid model for the 3D printers to use.
The red colored face is oriented in the wrong direction
Here is the model with all faces oriented correctly
Once all of the faces have been correctly oriented, the next step is to upload the model to be resurfaced. After resurfacing has been completed, the CADspan produces a link where you can download the .stl file. This all happens within the plugin and when working properly, there is no need to leave sketchup. Unfortunately, I had quite a bit of trouble with CADspan and was unable to get a .stl file for this model (subsequent attempts have proven to be more successful and after emailing the CADspan team about the issue I was eventually able to download the model). I was finally able to get a good file after opening the Sketchup model in Rhinoceros 3D and simply exporting it to the .stl format.
Printing I decided to attempt my first print with the MakerBot Replicator 2. I imported the .stl file into the MakerWare software and began printing using the default medium quality settings. I decided to cancel the build halfway through, as the printer had some trouble with the overhangs. I reloaded the model and tried again, this time enabling the supports option. I let this print run all the way through. Here is the result:
As you can see, there are some serious issues with this model. Firstly, the entire building is shifting off to one side. I am pretty sure that this has something to do with the speed of the default settings. The MakerBot was moving from side to side so fast during the print that the entire unit and table that it was siting on was shaking. Secondly, the support material is nearly impossible to remove. I tried a number of different methods to do this, but I just could not get all of it out.
For the final print, I decided to use the highest quality settings, reduced both the extrusion and travel speed down to 70, and enable the acceleration settings on the printer itself. Although not perfect, this print came out rather well. There are still a few issues with the overhang, but all in all I am happy with the result.
While the Replicator 2 was working away on its final build, I decided to try the model in the uPrint SE plus printer. This machine was a real pleasure to work with after the Replicator 2, as I simply uploaded the model into the CatalystEX software and hit print. The build went off without a hitch, and after a few hours in the chemical bath, I had a perfect model.
Final Thoughts All in all, It is no surprise that i had a better result with the build from the uPrint. After all, it is a much more expensive machine, and the cost of materials is $5 per cubic inch as apposed to $1 with the MakerBot (Although the VFL is offering free prints with the MakerBot until February 22!!!). However, the MakerBot required 5 or 6 attempts as well as hours of calibration to finally get an acceptable build. In the coming weeks I will be teaching a workshop here at the VFL on Sketchup modeling techniques and will cover in finer detail the process of turning the models into 3D Prints. so stay tuned for more information on that.