Keepout layer and board outline layer

[zd2020]

Hello,
Up to now, i was drawing the board layout with keepout layer. Then i select these lines and i give a command Design + Board Shape + Define from selected objects.
I watched "Altium Tutorial for Beginners - Starting with Altium Designer" video. And i saw that you are using a mechanical layer as a board outline layer. How the PCB manufacturer undestand that layer is board outline layer?
Would you please check the photo. Green line is Board Outline layer (Mechanical layer). If i don't put the pink keepout layer, polygon plane is covering that slot. How should i use the board outline layer and keepout layer?
Would you please explain me what is the difference between setting the keepout layer and board outline mechanical layer.
Thanks in advance.

[qdrives]

You use both. The mechanical layer is only for the board outline. The keepout layer may have more items on it that have nothing to do with the board outline.
The line width on the mechanical layer is generally thought of as the tolerance. The keep out is for how far you want the copper from the edge.

[robertferanec]

Also, to add to qdrives post, this may help (set Board Outline Clearance rule): https://designhelp.fedevel.com/forum...-to-board-edge