Dropdown List Parameters

Make your calculations interactive with selectable inputs.

You can turn any parameter with a predefined list of options into a dropdown selector using the viewer setting in the right-hand panel (RHS).

This allows users to choose from a set of options directly on the page. The selected value can then be used as an input in other parts of your calculation, making your page more interactive and user-friendly.

1D Dropdowns

• Create a parameter with a list (e.g. ["Option A", "Option B", "Option C"]).

• In the parameter settings in the right-hand side panel set the Viewer, option to list.

• The parameter will now render as a selection dropdown on the page.

• Not that the formula for your parameter will update to ctselect([array]), and cannot be edited when in list view. Switch back to a a parameter to edit the values.

Example parameter definition

Material = ["Concrete", "Steel", "Timber"]

This creates a parameter where users can pick between Concrete, Steel, or Timber, and the selected value can be referenced in your formulas.

2D Dropdowns (Label/ID Pairs)

You can also define dropdown options using a list of lists to separate user-facing labels from internal values.

Example Format:

List: '[[1, "One"], [2, "Two"], [3, "Three"]]',

In this structure:

• The second item in each inner list (e.g. "One", "Two", "Three") is shown in the dropdown as the label.

• The first item (e.g. 1, 2, 3) is the value that gets returned when the user makes a selection — this is referred to as the id.

This setup is especially useful when you want user-friendly labels on the interface but use more technical or numeric values in your calculations.