Are you working in a specific , or is 123448 a specific part number you need a technical drawing for?
This is the most common method. You draw a 2D profile (sketch) and "pull" it into a 3D shape. 123448
Joining separate mesh sections into one watertight volume using tools like or Blender . Are you working in a specific , or
If you have a collection of surface sheets that form a closed "box," you can use a Knit or Stitch tool to turn them into a single solid body. Are you working in a specific