Category Archives: Shell

The Shell Tool for Objects

Building the Pendant Globe

The shell tool is one of the most underused tools in ARCHICAD. I use it for almost any shape revolved around an axis, but it can also be used in place of morph and mesh type elements. In the following example, I will show how Grace used the shell to build a light fixture, but it can also be used to model decorative columns, newels, pickets and other trim elements.

Screen Shot 2016-04-19 at 9.21.16 AM

In the above image, the globe for the pendant light is a shell, the “whishbone” hanger is a morph and the pendant is a scripted cylinder. To start, draft the shape of the fixture and split it in 1/2 since the shell is revolved around a center point.

Screen Shot 2016-04-19 at 9.22.23 AM

Next set up the shell tool to trace out & revolve around the drafted shape. Set the structure to basic and the geometry method to revolved. Set the building material, surface and all pens for saving to GDL.

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The shell will be “horizontal”, so it will need to be rotated. Click on the end/center node and use the slant axis option from the pet palette (second icon/top row). Normally rotation needs to be started in a 3d view and completed in floor plan view.

Screen Shot 2016-04-19 at 10.02.41 AM

Scripting the Pendant Hanger

After the globe and bracket are modeled and placed in the correct location relative to project 0,0,0 all that needs to be done is save to an object, then script in the pendant portion of the fixture. This was covered at the last AC East Bay usergroup, and you can find more info from that presentation here.

The scripting portion is actually very simple. Start by adding parameters to adjust the length & radius of the hanging cylinder and mounting base; the four parameters at the bottom of the image below.

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Next, you only need to script two cylinders that reference the parameter variables above. CYLIND is the script for a cylinder shape and it references the cylinder height then radius seperate by a comma. The mounting plate needs to be adjusted to the top of the first cylinder, so an ADDz command that references the first cylinder length is needed.

Screen Shot 2016-04-19 at 9.45.07 AM

I also added a hotspot so the to the 3d script to allow the object to be placed on the ceiling in 3d view.