I'm not sure what an "attack angle" is, but if it's something like normal to the surface at some point, try created a smart point on a face and then create a Datum Axis selecting the Point and the Surface. Now you have a vector normal to the surface and since the point is actually a feature you can move the point using expressions and the vector will update, as it will if you edited the shape of the surface.
John R. Baker, P.E.
Product 'Evangelist'
NX Product Line
UGS Corp
Cypress, CA
Thanks John. As far a s"attack angle", I am designing a die that has a pierce operation. The "attack angle" is the angle that you would pierce the hole within a standard tolerance. With that being said,, I Have a compound surface and trying to locate that angle is giving me some trouble.
With the surface being a compound angle, there are 2 angles you need to find. The first angle is easy to find, the second one is a little tricky. How I do it is this:
I have a sine plate templete I created since that's wha he machinists use. I tip the part up on the first angle, then tip it to the second angle. This will make the work face normal to the tool/drill. It's harder for me to explain than to show, but this might get you in the right direction.
