Trouble subtracting

I am trying to subtract the green semi circle from the red design, for some reason it doesn’t work, it simply subtracts the extension of green leaving the original line I created the curvature with.

Any ideas why this happening

IMG_1754

What happens if you just extrude it then use the subtract tool?

I finally got it working last night, it took me about two and half hours. I had to subtract 2mm peice by peice, and that was when the project didn’t freeze and crash every three attempts…

Got to say it was a nightmare.

I tried extrusion subtraction from the top which failed every time , I then thought about it and for the last picture which I drew the extruded design and extruded it length wise and subtracted. It failed each time till I used a 2mm and extruded it peice by peice.

With the next release this will be fixed.