Within Limits—Discrete vs Ranged Parameters.BIMscript
Lawrence Lam • September 6, 2019
When it comes to working within BIMscript, a topic that gets a lot of attention is parameters. Specifically, how they affect your model and translate into each of the generated file formats. This fundamental building block enables items to flex, change materials and even add or remove geometry depending on configurations. There are two types of parameters—Discrete and Ranged—but they’re both applied differently. Let’s break them down.
Compare the difference.
The role of Ranged Parameters. These numerical values are only used in the Formula Editor part of the Plugin. Here you can call upon Ranged Parameters to create formulas that can be used in transformations. In BIMscript 3.1, there are no comparative functions of the script (e.g. IF and ELSE IF statements).
Discrete Parameters are dramatically different. These string values—which can be compared whether they match with the desired value or not—are only used in Script Editor part of the Plugin. This is where conditional branching is built. Discrete Parameters in Script Editor enables you to create the logic behavior of an object.
Control transformations. Define conditions.
When you want to control any translation for an object between a minimum and maximum value, Ranged Parameters are best. Let’s say you have a table that can be made in any width between 48” and 60”—that would be a Ranged Parameter. Perhaps you can change the shelf height within a bookcase, also a great use of Ranged Parameters. Rule of thumb: use Ranged Parameters when you need to control transformations (scaling, rotating or moving an object).
If you want to control how a model is configured based on defined conditions, Discrete Parameters are the way to go. Here an example would be an office chair that comes with or without armrests. You can set up a Discrete Parameter with the values ON/OFF, whereas each condition would control the visibility of the armrest.
Tackling the file types.
With parametric-friendly BIM systems such as ARCHICAD, SketchUp and Revit, Ranged Parameters are part of model properties and you can change values within that area. Discrete Parameters will also show up here, but for Revit BIMscript will generate a type catalog of each set creating a matrix. So if you have 2 Discrete Parameters with 4 options each, your type catalog will contain sixteen different combinations.
While attempting to download non-parametric files (static geometry) like DWG, 3DS and OBJ from a BIMobject Product Page, a configurator will appear. Here you can set up the product prior to downloading and the file will be configured on the fly. Voila!
Stay grounded in Discrete and Ranged Parameters by visiting the BIMobject Academy and navigate to the BIMscript section.