How to draw spiral in altium designer?
1- Go to Menu/Place/Arc/Arc(Edge),

2- Place an Arc close(but not necessarily accurate) to the desired dimensions,

3- While the arc is selected, On Properties panel, adjust all sizes including thickness, start angle, End Angle, Radius ,...

4- Go to Menu/Tools/Preferences/PCB Editor/General,

5- Change the Rotation Step to correct value. For example if your spiral has 5 wings, rotation step is 360/5=72,

6- Back in PCB editor environment, select the previously placed arc, then copy (ctrl+c), then paste (ctrl+v), then hit the space bar for one rotation step,

7- Repeat until you get your spiral,

8- You can even select your now complete spiral, then go to Tools menu, and click on Outline Selected Object, then hit the Delete key so the original spiral will be deleted and it's outline remain!