I have an assembly made via skeletal modeling technique (one hidden part controls criteria for other parts).  In one of the parts I have a hole feature.  I pattern the hole feature in one direction across the part.  All is well.  Then when I rebuild, sometimes that pattern spontaneously switches to the opposite direction, and the assembly loses its mind.  I have to go back to that part, edit the feature to change the direction, and then rebuild everything again.  All is well until the same thing happens again later.

 

Does anyone have an explanation or solution for this?
I'm using SW 2013, but I'm not sure it's relevant in this case.

 

I've attached the model, detached from the skeleton that normally drives its parameters.


Categories: Modeling and Assemblies

Comments
Last comment By: Glenn Schroeder   Wed, 16 May 2018 20:05:15 GMT
Re: Why does my linear pattern feature switch directions, and can I make it stop?

I've tried to use a plane or a planar model face, but it won't accept it as valid input for the direction.  So I use an edge, which I could see as not having a +/- characteristic, so therefore would be less stable.  But I don't know what my alternative would be if it won't take a plane.

By: Dan Morick  Wed, 16 May 2018 19:11:34 GMT
Re: Why does my linear pattern feature switch directions, and can I make it stop?

Dan Morick wrote:

 

I've tried to use a plane or a planar model face, but it won't accept it as valid input for the direction. So I use an edge, which I could see as not having a +/- characteristic, so therefore would be less stable. But I don't know what my alternative would be if it won't take a plane.

 

You should be able to use a plane, assuming you have one that's perpendicular to the direction you want to pattern.  For example, if you want to pattern up or down you can use your Top Plane.

By: Glenn Schroeder  Wed, 16 May 2018 19:21:38 GMT
Why does my linear pattern feature switch directions, and can I make it stop?

I have an assembly made via skeletal modeling technique (one hidden part controls criteria for other parts).  In one of the parts I have a hole feature.  I pattern the hole feature in one direction across the part.  All is well.  Then when I rebuild, sometimes that pattern spontaneously switches to the opposite direction, and the assembly loses its mind.  I have to go back to that part, edit the feature to change the direction, and then rebuild everything again.  All is well until the same thing happens again later.

 

Does anyone have an explanation or solution for this?
I'm using SW 2013, but I'm not sure it's relevant in this case.

 

I've attached the model, detached from the skeleton that normally drives its parameters.

By: Dan Morick  Wed, 16 May 2018 18:53:16 GMT
Re: Why does my linear pattern feature switch directions, and can I make it stop?

That's what I thought - I'd always done that in Inventor with no trouble.  But clicking on the planes has no effect, and clicking on a planar face selects the associated feature to include in "Features to Pattern". Maybe that's the real issue here.  <shrug>

By: Dan Morick  Wed, 16 May 2018 19:33:47 GMT
Re: Why does my linear pattern feature switch directions, and can I make it stop?

I prefer to use an axis instead a plane, but always try to avoid defining it by an edge. Edges can disappear with a cut, or a change in a extruded profile, splitting a line in a sketch, or just about anything. Faces are similar in their dynamic instability. If the pattern is not in the direction of a primary axis, then I can create one where it's needed.

 

Even though I've now described two ways that weldments can fail subsequent patterns, I think you may do well to create this as a L1.25x1.25x0.1875 ANSI angle weldment profile. What you have is stable, but weldments appear to be applicable to this part and likely other parts. Just saying, it's worth looking into and learning.

By: Tom Gagnon  Wed, 16 May 2018 19:39:55 GMT
Re: Why does my linear pattern feature switch directions, and can I make it stop?

As I said before you posted the Part, you can use a Plane for the direction.

 

 

If that still gives you trouble you can try this way instead.  Edit Sketch2, adding construction lines, fully defined with relations.

 

 

Then edit the Hole Wizard feature, adding points.

 

 

By: Glenn Schroeder  Wed, 16 May 2018 19:39:55 GMT
Re: Why does my linear pattern feature switch directions, and can I make it stop?

Make sure you have selected the direction box in the Property Manager before selecting the plane:

 

The pattern should then have the plane as a parent as expected:

By: Jim Sculley  Wed, 16 May 2018 19:43:05 GMT
Re: Why does my linear pattern feature switch directions, and can I make it stop?

Tom,

 

For a number of years I had axes saved in my templates to use for pattern directions, but since the enhancement allowing the use of planes I've removed the axes.  I've never had an issue with using them.

 

Excellent point about creating the Part as a weldment.

By: Glenn Schroeder  Wed, 16 May 2018 19:43:14 GMT
Re: Why does my linear pattern feature switch directions, and can I make it stop?

Thanks.  Apparently this is a 2013 issue: from the help file (image attached), planes are not valid input there.

 

 

I did it the way I did because in the skeletal model context the number of holes could change via an equation, and Hole Wizard would miss added holes when the part gets longer.  But maybe the suggestion of construction lines has some value.  I'll give it a shot.

By: Dan Morick  Wed, 16 May 2018 19:49:08 GMT
Re: Why does my linear pattern feature switch directions, and can I make it stop?

Good points.  I'll try using an axis.

By: Dan Morick  Wed, 16 May 2018 19:51:54 GMT
Re: Why does my linear pattern feature switch directions, and can I make it stop?

Dan Morick wrote:

 

Thanks. Apparently this is a 2013 issue: from the help file (image attached), planes are not valid input there.

 

 

I did it the way I did because in the skeletal model context the number of holes could change via an equation, and Hole Wizard would miss added holes when the part gets longer. But maybe the suggestion of construction lines has some value. I'll give it a shot.

 

I didn't realize you're using SW2013.  Sorry about that. 

By: Glenn Schroeder  Wed, 16 May 2018 20:05:15 GMT
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