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Assembly Constraints, Align , Align, Infer Centeraxis. Differences

Phenom
Phenom

I have sub assembly, that I have downloaded off of the internet.  I have a part I designed in NX.  I have these two parts in an assembly.

When I use the Align command with the align option, and I align the centerlines.  The sub assembly flips 45 degrees or so.

 

When I use the align with infer center axis,and I align the centerlines, the sub assembly aligns itself as it should and does not rotate. 

 

Please explain some possible reasons for the sub assembly flipping when I use the align with the align option.

 

Thanks

7 REPLIES 7

Re: Assembly Constraints, Align , Align, Infer Centeraxis. Differences

Siemens Phenom Siemens Phenom
Siemens Phenom

Hi sdeters,

 

Difficult to say on vauge information.... However are you consistent when selecting the lines to align - they have directional sense. If selected differently they might cause your flipping issues...

 

Best Regards

Fred

Re: Assembly Constraints, Align , Align, Infer Centeraxis. Differences

Phenom
Phenom

I have attached a simple NX 12 assembly.  Try Aligning The P*868 bore centerline to the shaft component.    If you use the align, with the align set in orientation, you will see the sub assembly rotate a bit.  If you do the same but change align to infer centeraxis, the subassembly does not rotate.  

 

 

 

Re: Assembly Constraints, Align , Align, Infer Centeraxis. Differences

Siemens Phenom Siemens Phenom
Siemens Phenom

Hi sdeters,

 

 

This is due to the directional sense of the entities selected and the solver. However there is a quick fix to your problem by using the "Reverse Last Constraint" on the Assembly Constraints menu during the creation - it will immediately realign to your default position or more the alignment there of. Have a look at the attached movie. you will see that the component is not rotated it is flipped.

 

Best Regards

Fred

 

(view in My Videos)

Re: Assembly Constraints, Align , Align, Infer Centeraxis. Differences

Phenom
Phenom

"directional sense of the entities"  I do not understand directional sense?  Is there a way we can visual see this?  Or display this?

 

But using the Reverse constraint will work.  Thanks for the help.

 

SHane

Re: Assembly Constraints, Align , Align, Infer Centeraxis. Differences

Gears Phenom Gears Phenom
Gears Phenom

@sdeters,

I think he means that some entities have orientations - like a line has a start and end or a plane has positive and negative direction. If you pick near the end of a line, that might cause the directions to be reversed compared to picking at the start end. Same goes for faces, theoretical centerlines/axes, etc.

 

I'm not sure about being able to display it onscreen.  I just get into the habit of looking for the reverse direction (dark blue arrows pointing opposite directions) or alternate solution (3 arrows arranged in a circular pattern pointing at numbers 1, 2, 3) buttons when dealing with constraints and using those icons to see if the results are what I want or not.

Tim
NX 11.0.2.7 MP11 Rev. A
GM TcE v11.2.3.1
GM GPDL v11-A.3.5.1

Re: Assembly Constraints, Align , Align, Infer Centeraxis. Differences

Siemens Phenom Siemens Phenom
Siemens Phenom

Hi sdeters,

 

I'm sorry if I was unclear but @TimF clarifies well.

 

Tank you Tim!

 

Best Regards

Fred

Re: Assembly Constraints, Align , Align, Infer Centeraxis. Differences

Gears Phenom Gears Phenom
Gears Phenom
@Sandman,

Not a problem - thanks for all of your help around here as well.
Tim
NX 11.0.2.7 MP11 Rev. A
GM TcE v11.2.3.1
GM GPDL v11-A.3.5.1