modifying sketches

[KT77]

SW user attempting to use IV 2009

I make a flat, square plate (sketch a square and extrude).
I save the part. I use the part in an assembly. But now I want to go back and lightweight the square plate. I edit original sketch, and add big circles inside (something I'm used to doing a LOT). But when I try to update the extrusion, I can't redefine the new closed area. I end up deleting the extrusion, unchecking 'all associated sketches bla bla', then extruding the sketch gain. But then it makes a big mess, and adds another copy of the sketch, and I have to fix all subsequent sketches linked to first one....

How do I redfine the extrusion after adding entities to the sketch? And not get a big mess to fix?

Believe it or not, this is not covered in ANY of the Inventor 2009 handbooks I have (even the advanced ones). Unbelievable.
TIA

 

[mcgyvr]

3 methods
1-hold down ctrl when trying to redefine the profile.
you will have to pick the circles and it will remove them. (however you can't really see where the holes are)

2- add the holes as another sketch (which is the better method anyways IMO).

3- just delete the extrusion (but uncheck the box for "consumed sketches and features") and extrude again after you change the profile with your holes.

 

[KT77]

#1 worked great. I wonder why this isn't in any of the Inventor books I have. It's such a necessary task.
Thanks mcgyvr!

#3 is what I resorted to, but made a lot more work to clean up.

 

[mcgyvr]

I've been using Inventor for over 7 years day in and day out and I have never had to do this exact situation. I always do #2 as its better IMO.