how to change the default direction of Arc with Polyline ?

[pippobaudo]

Hello guys,
can you help me with this question?

with Autocad 2010, when I draw an arc from Polyline it gives me convex arcs by default (open on the top), how to switch to concave with no need to use the option "Direction".
Lets suppose that I have the radius of the arc, then it is not possible to choose the direction after the radius; so if you know 2 points and the radius, how to switch the arc from convex to concave ?

I hope I am explained.
Thanks

[eldon]

AutoCAD always tries to draw arcs anti-clockwise. So try drawing your arc between your points in the other direction.

[HAWDesigner]

The direction of the arc really seems to depend on the location of the 3rd point relative to the 1st and 2nd points. Though, as Eldon pointed out, everything in AutoCAD rotates counter-clockwise. They are definitely complicated if you don't know what you're doing.

Here are a couple tutorials that may help to explain arcs better:
http://www.cadtutor.net/tutorials/au...ines-and-arcs/
http://www.dailyautocad.com/2008/11/...utocad_06.html

Good Luck!!