A 3d model file is loaded for any chosen text element in the 2d layout window. Z-level and rotation is set according to the text element. An additional rotation can be set in the parameter. The model search path is set in the setup dialog (setup/3d/modelpath).
For example, a text element with the text 'my-model.off' will load the 3d file 'my-model.off' from the folder set in the model path. The folder will be placed in the the same location with the same rotation as the text element in the 2d design. The 3d design is hierachical. If a model is used more than one time, the model will only be loaded once and a reference to this model is placed in the 3d design.