Using your Magic Wand: the hidden geometry behind Venn Diagrams
Recently, I created a fancy Venn Diagram to illustrate why you need to listen to a whole bunch of ArchiCAD experts talk about the same subject: IFC Mapping. But you knew that already because you’ve seen the diagram, watched all the videos, and read all the articles. This post in many ways is the polar opposite to all that high order BIM stuff that is IFC and IFC Mapping. But then again, both IFC and what follows are at their core about design, and that’s what we all want ArchiCAD to help us do.
How to Make a Venn Diagram
Have you ever made a Venn Diagram? Of course you have. It’s simple and obvious how to do it. Take two circles and make them overlap. But what about a Venn Diagram that is three overlapping circles? Or four? Or ten…how do you make sure the diagram itself is a beautiful composition and all the circles overlap properly? It turns out the secret is constructing the diagram around hidden geometry—specifically, placing the center of each circle on the vertex of a regular polygon with the same number of vertexes as circles required. So as show below, a three circle diagram is constructed around a triangle, a four circle around a square, a five circle around a pentagon, etc. If you follow this simple rule, your Venn Diagrams will be in perfect alignment. And by paying attention to the ratio between the radius of your circles and the distance between vertexes of the governing hidden shape (perhaps 1:1, 1:1.5, 1:2), you not only change the overlap of the circles, you also do so in a pleasing proportionality that propagates to all the subsequent overlaps between circles. I think it’s what makes the difference between a good Venn Diagram and a great one.
What does Venn Diagram creation have to do with ArchiCAD? ArchiCAD doesn’t have an obvious way to make polygons, like some other programs. For instance, many of us probably first learned a CAD program that could create polygons through the simple process of typing polygon, then the number of sides you want. But ArchiCAD isn’t CAD; it’s BIM. And we don’t need a tool dedicated to polygons because a polygon isn’t a THING that gets built. A polygon isn’t extra data about a thing. It’s either just graphics or a reference for element construction. As such it could be argued that the lack of a polygon tool is purposeful and reinforces how one should approach working within ArchiCAD.
However, if the polygon is a thing that needs to get built, then it should be constructed using the appropriate Tool (Wall, Beam, Slab, etc.) or using the Polygon Prism Object, Prism Object, or another Basic Shapes Object if there isn’t a specific Object that better suits your purpose. (BONUS TIP: For some reason this has me thinking about MAKING objects. For some videos on that, click here and here).
That all said, there are clearly times you need to create polygons for various reasons—such as Venn Diagrams. So what’s the best way to do it?
Hidden Powers of the Magic Wand
We probably all use the Magic Wand all the time. It’s a great way to create Fills or Slabs within a region, place Walls above existing Walls that you can see in a Referenced Story, add contours to a Mesh, etc. There are so many uses. And if you want to quickly draw basic shapes like pentagons, dodecagons, or octacontakaitrigons (yeah that’s a thing, look it up), the Magic Wand is also your tool. The trick though is to know that you can change how the Magic Wand acts when you hold down the Space Bar and click.
(To save us all time, I’ve copied and pasted the Help Center article on the Magic Wand Settings. It is super clear, so there’s no point in me rewriting them. AND you need to read them, so I’ll save you a click by just including them here).
Magic Wand Settings
Use the Options > Magic Wand Settings command to open this dialog box.
When creating curved Walls and polygon-type elements based on Arcs, Circles and Splines, the approximation is based on the state of the Magic Wand Settings dialog box.
With the two radio buttons on the right, you can choose between two tracing methods.
- Best Match: Curved segments (when applicable) will follow as best as possible the natural form of Circles, Arcs and Splines.
- Prefer Linear Segments: Only linear segments are used.
The four radio buttons on the left allow you to choose from a set of options to approximate curves with linear segments.
- Deviation from Curves: Enter a value to define the maximum deviation of the polygon from the original curved element.
- Segments Along Arcs: Define the number of segments along an Arc.
- Segments Along Circles: Define the number of segments along a Circle. In this case, arcs will be transformed into a number of segments corresponding to the part of the circle they represent.
- Segment Length: Enter a value to define the segment length for transformations resulting in segments of uniform length.
Note: If you choose the Best Match method and real curves cannot be created, ArchiCAD will try to approximate curves in the hierarchical order represented in this dialog box.
How to not Draft any Regular Polygon
By changing the Tracing Method to Linear Segments and setting the Segments Along Circles to the number of sides you want, you can turn the Magic Wand into a regular polygon making machine. Once you’ve made this change, all you need to do is Magic Wand a circle using whatever Tool you want to have the shape created with. It’s worth pointing out that you can use almost any 2D or 3D Tool when using the Magic Wand to create polygons in this way (though oddly enough the Morph Tool will still trace the circle rather than create a circumscribed polygon within the circle). Also since you can use 3D Tools, you can also create these shapes directly in the 3D window, if the circle you are using is also a non-Morph 3D element (like a slab). Typically though you’ll be making Polygons for reference purposes and the best Tool to use is the Polyline tool so that the resulting polygon is one unified element.
So the next time you are designing something and need some aspect based on a polygon, use the Magic Wand. Don’t waste your time trying to construct the shape the old fashioned way. Remember, sometimes the secrets of using ArchiCAD aren’t about Social Big BIM, but about doing the old stuff faster.
Other Unintentional Secrets of ArchiCAD Power Users
Very Important Final Note: remember to change the Magic Wand Settings back to “Best Match” after making your polygons, otherwise you’ll be in for a surprise the next time you use the Magic Wand for your typical needs.
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