Sketch - what to constain to??

[sijcooke]

Hi,

Please can someone give some advise on this!!

I have attached a part. On this part, sometimes there will need to be 4 flanges, sometimes 3, sometimes 2, 1 and sometimes none. The flanges will be turned on and off with ilogic.

Currently if you turn off a flange the small cutout sketch causes an error due to the geometry missing. What is the best way to constrain this cutout, so that regardless of what flanges are suppressed or not, it doesnt cause errors!

The only way i can think of is to constrain to the center plane or center point origin?

Thanks,

Sijcooke

[WHolzwarth]

Constrain it relative to origin. Oh, I've seen you noticing that already.

[Curtis_Waguespack]

Hi sijcooke,

It depends on the intent of the design, but if the part Length and Width are going to change configuration, then it is likely best to constrain to the outer edges rather than the center origin planes.

Try this:

• Edit your Cut feature sketch
• Delete the projected edges leaving the sketch under constrained
• Then exit the sketch.
• Then drag the Cut feature above the first flange in the browser
• Then edit the sketch again
• Project the out side edges of the face and constrain the square cut out profile
• Exit the sketch

Now you can suppress the flanges and configure the length and width with ilogic and the Cut feature will hold to the out sides of the part (assuming that is the intent of the design).

I hope this helps.
Best of luck to you in all of your Inventor pursuits,
Curtis
http://inventortrenches.blogspot.com

[sijcooke]

Hi All,

Thanks for the replys. This all makes good sense.

The part i attached to my post is a very simple part, but the actual part i am working with is quite a bit more complicated, with contour flange, lots of flanges, different cuts, holes etc.

The more complicated part was all drawn before the problem becomes apparent, so the problem with moving the cut to above the flanges on my more complicated part is that moving it will cause other features to throw errors... 

I guess in this case it may be best to re dim everything from the center origin, and the dimension will have a value like... (PlateLength/2)-10... to put the cut 10mm from the edge?

Thanks,

Sijcooke