How to Add Rotation Parameters to a GDL Object in Archicad?

In Archicad, you can add custom rotation parameters to a GDL object, allowing you to control its orientation on the X, Y and Z axes directly from the parameters panel. This technique is especially useful for objects such as light fittings, technical elements or components with variable orientation.

Step 1 - Open the object in the GDL Editor

1. Select the object in the project or from the Library Manager.
2. Open it in the GDL Object Editor.
3. Go to the object's Parameters section.

Step 2 - Create the rotation parameters

In the Parameters section, create three new parameters to control the object's rotation on each axis.

1. Add a parameter named rotatex and set its type to Angle.
2. Add a parameter named rotatey with type Angle.
3. Add a parameter named rotatez with type Angle.

By default, you can assign them an initial value of 0°.

Note: It is important that the parameter type is Angle and not numeric, to ensure correct behaviour in 3D transformations.

Step 3 - Apply the rotation in the 3D Script

For the parameters to work, they need to be applied in the object's 3D Script.

1. Go to the 3D Script section of the GDL editor.

2. Add the rotation commands, referencing the previously created parameters directly:
   rotx rotatex
   roty rotatey
   rotz rotatez

   

The recommended order is to apply the rotation on X first, then Y, and finally Z, to achieve predictable object behaviour.

Step 4 - Check that the object works correctly

1. Save the changes to the object.
2. Place the object in the model.
3. Open its Parameters and change the rotation values.
4. Check that the object rotates correctly in the 3D environment.

For example, assigning 180° to the rotatex parameter will completely flip the object over the X axis.