I want to add an Extrude of 10 mm at the bottom of the model without affecting the openings created with shell command present below. In Creo, there is no multi body function so I am unable to do so. Please guide me how to do it in Creo 4.0
Can you elaborate on what you are trying to do? I assume that the bottom is the 3 rectangular openings. Assuming they are coplanar, you can extrude on that plane and lengthen those openings pretty easily. But it seems like you are trying to do something else. Please clarify.
I managed to create it. First I extruded the rectangle then created the cavity along the previous shell using the Blend tool.
Ah, this makes more sense now.
Regarding your original approach, the extrude could have been made as a capped surface, the internal surfaces of the 3 outlets copied and extended, the copied surfaces merged with the extruded surface and then solidified.