About Planar Walls
Use the Planar Wall tool to create a planar first wall or one or more unattached planar walls. While you can use the tool to create the side walls of a design before creating the First wall, you must connect or merge the walls to complete the project. Create a closed loop for your planar wall sketch. Use the tool to set the sheet metal thickness for the first planar wall. Any other walls that you create automatically use the same thickness.
Click Sheetmetal > Planar to access the Planar Wall tool.