You can perform takeoff on a 3D model from the Takeoff Types panel in the Takeoff viewer.
While viewing a model, click the Takeoff Types
icon in the left navigation to open the Takeoff Types panel.
From the Takeoff Types list, select the takeoff type to use for your takeoff.
Select one or more objects directly on the model in the viewer.
Add selected objects to the takeoff by clicking the blue box beside the takeoff type they belong to in the Takeoff Type list.

Takeoff items appear in detailed takeoff view for the takeoff type and in the inventory for the takeoff package.