Hi @Elmoataz.Bellah.Salem, Are you working with custom subassemblies? if so, and you are using Civil 3D 2023.2 or newer, you can harness the power of subassembly management. Go to the toolbox, look for the subassembly collection, and right-click on the subassembly you want to select:
![ecfernandez_0-1717934157726.png ecfernandez_0-1717934157726.png](https://forums.autodesk.com/t5/image/serverpage/image-id/1373756i8A1250FB3F662E84/image-size/medium?v=v2&px=400)
This will select all the subassemblies.
Alternatively, you can open the quick select window and create the following selection set. At value place the name of the subassembly you want to select, then hit OK and you'll have selected only that subassembly (see the following images):
![ecfernandez_1-1717934328895.png ecfernandez_1-1717934328895.png](https://forums.autodesk.com/t5/image/serverpage/image-id/1373757i362B95CEB9B6EDEC/image-size/medium?v=v2&px=400)
My subassembly was called, ShoulderDemo
![ecfernandez_3-1717934359040.png ecfernandez_3-1717934359040.png](https://forums.autodesk.com/t5/image/serverpage/image-id/1373759i776ABB8E5CF53E8A/image-size/medium?v=v2&px=400)
Give it a try. I hope this helps.
Best regards!
Camilo Fernández
Civil engineer | Specialist in design, construction, and maintenance of roadways
![EESignature EESignature](http://autodesk.i.lithium.com/t5/image/serverpage/image-id/1272565i464DC3DC646B4F11/image-size/original)