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PTC_CONSTRAINT_SET and distance calculation

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Re: PTC_CONSTRAINT_SET and distance calculation

I'm not really sure how PTC handles these technical support cases, have you heard anything from them yet?

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Re: PTC_CONSTRAINT_SET and distance calculation

Yes and no.  They asked a couple of follow up questions after I opened the case, but I haven't heard back on why the behavior is happening yet.  I'll let you know when I do.

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Re: PTC_CONSTRAINT_SET and distance calculation

As you suggest, string type parameters should work great for those multiple-choice scenarios.

You could also use parameter of integer type (though the coding would have to be documented - which is a good thing).

In general, I think that parameters are more appropriate for storing and manipulating the "meta" information about the model, while dimensions should just describe feature locations and sizes.

So, frankly, I think that your implementation of using the dimension values to encode "state information" is an inventive hack which will be hard to maintain and to explain to new users.  Nevertheless, I don't see why it would cause the demonstrated weird behaviour - therefore I am curious about PTC response.

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Re: PTC_CONSTRAINT_SET and distance calculation

Where does L1_DIST and L2_DIST come from in your model? I can't seem to find parameters with those names on any level?

 

The main difference between my model and yours seem to be that you have attached the components to a number of level planes (I don't think I could use this method as I might want to place the components on any side of the component named ground) rather than it being constrained to a distance from the assembly coordinate system origin, which made me wonder - If I want Creo to do more than one distance calculation (one for each constraint set) the correct way to do this is

 

IF CUBE==1&SPHERE==1&PYRAMID==0

D31=500

D26=500

 

Right? I have also tried

 

IF CUBE==1&SPHERE==1&PYRAMID==0

D31=500&D26=500

 

But that gives an error.

 

I have now also tried using integer, yes/no and string parameters instead of real number, but the same behavior as before occurs in my model.

 

PARAMETER is real number, as used on the first page of this thread. PARAMETER_1 is integer type, PARAMETER_2 is yes/no and PARAMETER_3 is string type parameter. It doesn't seem to matter (to Creo) which one I use.

 

 1_1.PNG1_2.PNG2_1.PNG2_2.PNG3_1.PNG3_2.PNG

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Re: PTC_CONSTRAINT_SET and distance calculation

 


@avero wrote:

Where does L1_DIST and L2_DIST come from in your model? I can't seem to find parameters with those names on any level?

 

L1_DIST and L2_DIST are just named dimensions - they control the distances between the level planes.

 

The main difference between my model and yours seem to be that you have attached the components to a number of level planes (I don't think I could use this method as I might want to place the components on any side of the component named ground) rather than it being constrained to a distance from the assembly coordinate system origin, which made me wonder - If I want Creo to do more than one distance calculation (one for each constraint set) the correct way to do this is

 

IF CUBE==1&SPHERE==1&PYRAMID==0

D31=500

D26=500

 

That should work... (see below)

 

Right? I have also tried

 

IF CUBE==1&SPHERE==1&PYRAMID==0

D31=500&D26=500

 

The above syntax is not correct.

 

 

But that gives an error.

 

I have now also tried using integer, yes/no and string parameters instead of real number, but the same behavior as before occurs in my model.

 

PARAMETER is real number, as used on the first page of this thread. PARAMETER_1 is integer type, PARAMETER_2 is yes/no and PARAMETER_3 is string type parameter. It doesn't seem to matter (to Creo) which one I use.

 

 1_1.PNG1_2.PNG2_1.PNG2_2.PNG3_1.PNG3_2.PNG


So just as you were saying all along, it seems that there is a bug in the software because changing value of dimensions that belong to inactive constraint set does not update the placement (the value changes, but system does not regenerate the component in the new location).

 

This is very hard to explain well, so I attach the model for your review.

ptc_constraint_set_demo-2.png

if link3's constraint set "Upright" is active because link3_rotated parameter is set to NO, then changing the above relations to offset_upright = 0 and regenerating will lower link3.

However, if instead you change the above to offset_side = 0, then set the value of parameter link3_rotated to YES, and then regenerate - this will leave the link3 in its old location (44 units above).  Then doing the "edit definition" will snap it back to the new setting of 0.

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Re: PTC_CONSTRAINT_SET and distance calculation

I don't think you attached the model as you intended, but I understood the explanation. It seems we agree this must be a software bug then; you should be able to change values of currently inactive constraint sets and the components should then be placed correctly when the active constraint set changes upon regenerating the model. This doesn't seem to happen when you manually edit values of inactive constraint sets though, only when using relations.

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Re: PTC_CONSTRAINT_SET and distance calculation

Just to follow up on this, an SPR has been filed and R&D is supposed to be taking a look at this.  I'm not expecting to hear anything back until some time in January.

 

https://www.ptc.com/en/support/article?n=CS318195

 

https://support.ptc.com/appserver/cs/view/spr.jsp?n=9618855

 
 
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Re: PTC_CONSTRAINT_SET and distance calculation

Latest update from tech support:

 

"A fix to this SPR has been submitted to Creo 6.0.4.0 which is scheduled for release mid-late February.  After retrieving the assembly, edit the definition of the cylinder part and complete and the process outlined in the case and post will behave as expected – the cylinder will use the correct placement location and orientation."

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