May 3, 2012
Objet guest blogger Piet Meijs is Senior 3D Expert at Rietveld Architects, New York. The most asked question I get from architects is: “What software do you use?”. The answer is always long since we don’t like to limit ourselves to just one solution, but we of course have a preferred workflow, which I’ve done my best to describe in full below.
3D Computer Modeling
Like most architectural firms, we do all of our drafting on the computer. (We also do our hand-sketching on computers, but that’s a whole different blog post…). At Rietveld, our main software package is Graphisoft’s ArchiCAD. ArchiCAD is what’s called a “Building Information Model” (BIM) software. This means that the model becomes a database containing geometrical as well as non-geometrical information of the design. The non-geometrical information consists of data such as cost, quantity, type, etc. We will come back to this later, but let’s first talk about the geometrical information.
It seems obvious these days that a design is drawn in three dimensions (3D). However, not too long ago, most architectural firms only drew in two dimensions (2D) and some still do. Advances in software however have made it a lot easier to draw in 3D. This became a huge advantage for when you needed to make a 3D presentation (or rendering) for a client. No longer did you have to create a separate file for rendering a 3D image in a software that did not have the capability to represent that design in 2D.
So, now that we have our design drawn in a software package that can handle 2D and 3D representation, wouldn’t it be great if we could hit “3D print” and have our design 3D printed to scale? That would be great, but unfortunately the technology isn’t there yet. We will come back to that later as well.
Just as with the beginnings of 3D rendering where you had to make a separate file for every different usage, the same also holds true here. Since the technology of 3D printing is still quite new, the software that architects use hasn’t caught up yet. Once you accept this, it opens up a whole new array of possibilities, since you are no longer tied to your main software package.
Our Workflow
Our workflow was created mostly by looking at what we knew at that time, and what we already had available to us in our office. But it is by no means the best, or only, workflow.
When we start a project, the basic geometry is drawn up in 2D lines in ArchiCAD. This project geometry serves as the basis for all the 3D computer models that will be made, whether it’s for 2D drawings, 3D renderings, or a 3D print model. For the 3D print model, we like to use SketchUp. This seemingly basic program is actually very suitable for 3D printing. The geometry it creates is very simple, and therefore very clean. Bad prints are almost always caused by bad geometry. Once the model is complete, it gets exported to Rhino where we apply a few grasshopper tricks to texture certain surfaces and to check if our geometry is watertight. Sometimes certain surfaces don’t get exported or were accidentally deleted in SketchUp. Rhino has plugins to detect these “naked edges”. Once the model is done in Rhino we export the model as an “stl” file. This file gets imported into the Objet 3D printer’s software which handles the actual 3D printing of the model.
As said before, this is just one solution. Any program that can built watertight meshes can be used. Even NURBS modelers can be used, as long as you keep in mind that the model becomes a polygon model when exported to an “stl” file.
The Future
I started this post with talking about the changes architecture software went through to accommodate the need for 3D representations of the design. Software manufactures worked hard to integrate 2D and 3D into one software package, and they have succeeded. So the next step should be the integration of 3D printing.
I like to use the example of ArchiCAD. ArchiCAD has a library filled with pre-built library parts. These library parts range from furniture to columns, and everything in between. The best thing about these library parts is that they have multiple appearances. They have a plan view, elevation view, section view, and even a 3D view. Also, you can make the library parts appear different in different scaled drawings. A door frame in a 1:100 plan can be a simple box, but can show up very complex in a 1:5 detail drawing. I would like to see this same logic used to create 3D printable library parts.
Since this technology is already available for 2D, it’s only a matter of time until this will be available for 3D. All you’ll have to do then is press “3D print”.
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