Sketching in Assembly NX6

[dougkeuneke]

Why can't I constrain/dimension a sketch to multiple components on an assembly. I'm only able to pick edges of the component who's surface I used as the sketch plane (and I get a linked feature in the model tree). If I pick a datum plane as the sketch plane then no component edges can be picked. Note....The all edges will hilite with select filter set to "entire assy", but that option goes away for constraining and dimensioning. Any help would be appreciated.

Doug Keuneke
Orion-KSC

 

[jerry1423]

You should be able to do it if you WAVE link then, or PROMOTE the bodies.
Can you explain what you are trying to accomplish ?

 

[kapmnit123]

Hi Doug,
You are right the "ENTIRE ASSEMBLY" option will not work in your case (sketch constraining).
As Jerry told Wave Linking is the one of the way out (in case of a top-down assembly).

Secondly (my apologies if i got it incorrect in case of NX6).... use Project Curve to reference the other component entities (ENTIRE ASSEMBLY option should work here ...at least this is the case in NX8).Also note to keep the CREATE INTERPART LINK option ON (this is just besides the ENTIRE ASSEMBLY option) if you want the constraints to be associative with the reference geometry.

In case it doesn't work (i am 50/50 sure on that as i have a feeling that perhaps the CREATE INTERPART LINK option came into picture after NX6) ...go with what Jerry told.Take a wave link and use it as a reference.


Do share the exact detail with us so we can provide other possible workarounds also.

Best Regards
Kapil Sharma

 

[dougkeuneke]

Thanks guys...the assembly is a large ring weldment, a 12 sided polygon made of 4 x 6 steel tube. Each segment has 3 hinge attach plates welded to the top surface. The original design requires 3 x 3 angles spaced between the plates to provide for welding of downstream floor plates. My problem is that while doing the drawing I noticed that the angles are all over the place, unequal spacing between hinge plates and varying offsets to inside ring surfaces. Using my ProE experience I assumed I could sketch on the top surface and essentially layout where the angles should be...then update the models accordingly. I have always used sketches in assembly for a variety of reasons, they're cheap and capture design intent. I know I can accomplish this in other ways...but am surprised NX does not have this simple but important tool. Still learning and won't give up.

Doug

 

[kapmnit123]

Hi Doug,
I presume you are mentioning the skeleton modeling in PRO-E. In NX we create a top-level sketch which can be referenced out at all the component levels using wave linking.I worked on a heat condenser assembly 2 years back and followed the same procedure.Create the layout sketch at the top-assembly level and then reference out the entities at the component level (you need not take reference of the entire sketch but rather go for a selective selection too.)
Also NX provides you doing the same through interpart expression linking.
Best Regards
Kapil Sharma

 

[jerry1423]

What I have done is create a sketch in the assembly file and constrain the components to that.

 

[dougkeuneke]

Thanks for your input.... but I'm trying to create a simple sketch on the existing components in the assy, not the other way around. I have found a way to do what I want by creating datum points at the component verticies before i enter the sketch. Now I can create sketch geometry that can be referenced.

Doug