On Land

Environment Information
At Rill Architects we run ArchiCAD on Mac OS X. If you work at Rill, this is your stuff. If you don't, but you work in ArchiCAD, you may find something interesting. Anybody else, I don't know.

Location: 32 Exterior Improvements /

Update: Japan and Alaska.

I needed a US flag, and I didn't have my own, so I searched in the settings dialog. The US Archicad Library doesn't have one either. There is one on BIMComponents, written by Graphisoft, and maybe that one is in the international version library. It's just as well, because the object (Flag.gsm) doesn't offer the US design.

In fact, it doesn't name any countries. It is charmingly purely parametric: Choose the number of stripes, their direction, and their surfaces. In this way, they can cover lots of the flags of Europe. There is also a cross option to address Scandinavia. UK? Haha no.

This Graphisoft flag looks really good. It is waving, compound waving even, and it droops just a bit. The code is classic morphbarf, though I wouldn't know how to create such a morph in native Archicad. It was likely done in a proper freeform modeler, imported to a morph, and then saved as an object. Their trick is to slice up the waving flag geometry with CUTPLANEs in various proportions and directions, depending on those non-national parameters, and then apply colors to the slices. So Hungary and France and everyone have different stripes with the exact same waving.

But now we can see why there is no US, UK, or Canada version. The stripes and crosses are all simple straight cuts, and sometimes flags need closed and nested polygons, many of them. When I have to weave together a lot of weird geometry, I head for the group operations, the GDL equivalent of SEOs.

I appropriated the morphbarf and abandoned the rest. (The license on Flag.gsm is Attribution-No Derivatives, but the editor offers limited choices - seems like ShareAlike would be better. Graphisoft please get in touch if you have any concerns.) The operations used are subtraction (SUBGROUP) and intersection (ISECTGROUP). The flag parts' geometries are made via PRISM_, and the trick there is to slope them down to match the droop of the morph. (Tip: (-1) * SIN(droopAngle) * horizontalDistance) Some shapes are subtracted from others, such as the stars in the blue fields. Then each finalized PRISM_ is intersected with the morph geometry, which creates chunks of waving stuff with the different colors.


The leaf translation required some thinking, but I developed a general method that should come in handy again.

In exchange for the morphbarf I am happy to offer the finial and the tapered pole.

As of this writing I have the US (needed), Texas (so simple, and someone might need it), Puerto Rico (requested), and Canada (who doesn't like Canada). Next is probably DC (easy, local) and Alaska (I just like that one). Japan? Having done the maple leaf, I can see the UK from here, which would lead to AUS and NZ. Anything with a fancy seal or heraldry (Mexico, half the US states) will require different techniques. Staying away from Maryland for now.

Download here.