Referencing external pattern table

[Bob_W]

Pulling my hair out on this one. I am using WF4 and Skeletons to try a top level design.

To start with I created a skeleton in an assembly that has 6 datum points patterned using a table. As a test, while still in the skeleton part; if I extrude a cylindrical feature using the first point I have the option to use a reference pattern for the new feature and it works as expected.

Now if I use copy geometry and bring the skeleton references into a new part I can no longer reference pattern a feature using the point from the skeleton. This is using the same method of creating the pattern while the skeleton is active but it won't work in the new component. I do have the option "default_ext_ref_scope" set to yes. I can use all the points individually as a reference but I just can't reference pattern a feature to the skeleton.

Like most things, this should not that difficult, but I am just not getting it today. Any suggestions would be appreciated. It doesn't work with a dimension pattern either.

Bob

 

[kdem]

Don't know if this is the problem since you don't specify how the copy geometry is created but to reference pattern copy geometry or publish geometry features you need to have this in reference patterns as well. Most people make the pattern and copy all the instances in a single copy geometry or publish geometry feature. When you do this it breaks what I call the reference chain. Example, creating a pattern of holes, add a washer and reference pattern it, add a fastener and reference pattern it. Copy geometry and publish geometry need to follow the same logic. Create you pattern in your skeleton, when you use the copy geometry or publish geometry featureselect the pattern leader only as the reference feature, pattern the copy geometry or publish geometry feature and reference should be selected, add your geometry and you should be able to reference pattern as long as there nothing else that interfers with doing so.

 

[Bob_W]

I had a reply typed and entered the wrong code and lost it. I will try again later and hopefully upload some simplified files.

Bob

 

[Bob_W]

OK, I finally got back to this problem again and made up some simplified
models. I did find that when working with an activated part in the
assembly model I could get the pattern to work. This appeared to be a
result of being able to pick the lead reference point that is from the
skeleton. When I try to create features in the part model, the lead
skeleton point is not available only the copy geometry points are
available and those will not reference pattern. Is there something else
I should be doing that will allow me to work with the part model
without being in the activate mode in the assembly?

I also noticed that PNT1 in the skeleton shows up as PNT1_1 in the ext copy geometry. All other points are the same.

Bob



2012-03-02_103902_Test.zip

 

[dgs]

Read kdem's reply again, it will work. Here's the steps
I take:

<ul>
[*]Create pattern in the skeleton
[*]Create a publish geom in the skeleton containing only
the pattern leader, nothing else.
[*]Pattern the publish geom by reference
[*]Create a copy geom in the part and reference only the
lead publish geom.
[*]Reference pattern the gopy geom
[*]Create your geometry referencing the copy geom
leader
[*]Reference pattern the geometry feature
[/list]

The key is patterning at every step in the chain and
having only the pattered geometry in the publish / copy
pair.

 

[Bob_W]

Doug:



I finally got it to work by using your step by step method but I had to
buy another mouse since I wore out the buttons on the first one

This must probably rank up at the top of the list of PTC's most
convoluted features. I had gone through the help center which turned up
nothing and there was no chance I could have gone though this without
your help. Do you actually need a copy geometry for each patterned
reference that is going to be used? If I have a dozen or so point sets
then I am guessing that I would need all these copy geometry features to
get this to work. Is that correct?



What is different when I activate the part model in the assembly and
then create a feature using the lead skeleton point? That will pattern
the feature as expected, but does it lose references or create other
problems?

Got the code wrong again, but at least I am learning to copy and paste a little better.



Thanks

Bob

 

[dgs]

Yep, you need one for each. If you are copying non-
patterned geometry, it can all go into one.

You can remove the publish geom (steps 2 & 3) from the
process and directly reverence the lead member in the
skeleton pattern within the copy geom. That will save you
some mouse workout.

The publish geom has value when gathering sets of data, but
in this case we aren't gathering a set so it's really not
worth the extra clicks.

 

[Bob_W]

Thanks again Doug. I just missed a step with Kdem's reply and it didn't work as a result.

I suspect this hasn't changed any in WF5 so we will just have to wait to see if this ever gets simplified. I just hope I can remember this next time I need to try it. Sometimes I think I am getting too old for this stuff

Bob

 

[kdem]

As Doug said yes you need a copy geometry for each one. If you go back to the hole, washer, and fastener you can see why. In this example you:


1.Add a hole and pattern it.


2. Add a washer using the hole as a reference which allows you to reference pattern the washer.


3. Add the fastener which uses the washer as a reference which allows you to reference pattern the fastener.


You can think of your test assembly in the same frame work.


1. You have your point sets which is a point that is patterned. This feature is in the same position as the hole in the previous example.


2. Your copy geometry feature is in the same position as the washer. To be able to reference pattern later features this has to be a pattern or reference pattern.


When you add all the points to a copy geometry feature it references them individually there is no pattern information in the copy geometry feature. Think of this as being similar to a datum point feature with multiple points in it. You can use the individual points as references for geometry but you can't create geometry at the first point in the feature and reference pattern.


3. Your extrude geometry is in the same position as the fastener. Since it references the copy geometry the copy geometry has to be a pattern or a reference patternso you can reference patternthe extrude geometry.


This is why you select the pattern leader for the copy geometry and reference pattern it.

 

[Bob_W]

kdem:

The sequence does work but in this day and age of computers I just don't see why this still has to have as many steps as it does. If I have a part that has a patterned series of holes and then assemble this part into an upper level assembly. The pattern is still useable. In the assembly model I can now assemble one bolt to the lead hole in the component and the bolt will reference pattern. I do not have to pattern the holes again after I brought the part into the upper assembly.

Bob

 

[kdem]

I'm not making any statements about how things could or should be easier just how I see things workinging in ProE and how they relate and compare.


What you're describing wouldskip the creation of the copy geometry (relating it to what you are doing in your test assembly) and directly reference the pattern in the skeleton which you can do and get the extrude to reference pattern. I think you're still not seeing what I'm saying about how things relate and compare between your test assemly and the example I gave.


Here is another example that might be easier to see and how it would relate and compare to what you are doing in your test assembly:


1. Create two parts and create a pattern of holes in the first one. This would becomparable tothe pattern of holes in your skeleton.


2. Create a hole in the second part that references the pattern leader in the first part. This would be comparable to the copy geometry in your OM part.


3. When you add a fastener to the assembly or create geometry in the second part you reference the hole in the second part. This would be comparable to your extrude feature referencing the copy geometry feature.


When you pattern step 3 reference won't be selectable because of how you defined your constraints or references (depending on whether you add a fastener to the assembly or add a feature to part 2) and because the hole in the second part is not patterned. This is different than what you described in:





The sequence does work but in this day and age of computers I just don't see why this still has to have as many steps as it does. If I have a part that has a patterned series of holes and then assemble this part into an upper level assembly. The pattern is still useable. In the assembly model I can now assemble one bolt to the lead hole in the component and the bolt will reference pattern. I do not have to pattern the holes again after I brought the part into the upper assembly.


End Quote


If you changed step 3 so when you add a fastener or create geometry in part 2 you reference the pattern leader in the first part your fastener or geometry should be able to reference pattern and this would be comparable to what you described in your quote above. This is different from what you are doing in your test assembly as it removes step 2 and changes step 3.


I would post files but I'm not using WF4. I'll try and post snap shots if you would like to see what I'm doing.

 

[Bob_W]

kdem:

thanks for taking the time to go through this. I think I will try making an assembly like you described so that I can see the differences a little more clearly. Once I actually do that it will help me understand it a little better. I have already set up the publish geometry per the previous instructions and should be able to use it to work on the actual parts next week. Seems like every time I tried to play with this today I got side tracked on stuff I am actually supposed to be doing

Currently I am looking at this method to see if it would be useable in our parts and assembly to reduce time to create or revise some of the models we use.

Thanks again and have a good weekend;

Bob

 

[dgs]

I see the logic in how it does work, but I can certainly
see room for improvement.

If you select individual points inside the copy geom, Pro/E
copies the points. It doesn't care if they are patterned
or not, it just sees points and copies them in. If you
want to capture the pattern info, you need to go through
some more work to do so.

Now, if we could select a pattern inside the copy geom and
have the 'smarts' of the pattern come along, that would
make things much nicer.