A negative extrusion is created in exactly the same way that the user would position Panel Vertex elements to define the shape of a 2D Panel Loop and then extrude this by the required thickness to create a 3D Panel. Refer to for more information.

On the WALLS AND FLOORS tab, in the Create group, click Floors, select Screed from the drop-down list to display the Create Negative Extrusion window.

The functionality available for selection from Create Negative Extrusion window is identical to the functionality available from the Create Negative Extrusions. Refer to Create Negative Extrusions, for more information, on the functionality of this window.