This section applies only if you do not have access to SpaceClaim. In that case, you can also use DesignModeler (the older geometry engine) to specify your parameters. In order to do so, open DesignModeler by double-clicking on from the Project Schematic window. Then expand XYPlane. Next, highlight Sketch1.
Now, check the box to the left of "R3," which will be in the "Dimensions: 3" part of the "Details View" table. When you check the box, an uppercase "D" will appear within the box and you will be asked what to call the parameter. Call the parameter "DS_R."
DesignModeler can now be closed.