Trying to pattern a simple chamfer results in error

[Anonymous]

Hi, 

Not sure if I'm doing this wrong (probably am), or this is an error on the system. I'm doing a very simple part, made some patterned extrusions to create some fingers, and now I want to chamfer those fingers with a similar pattern (those are going to be driver by parameters, which is why I need them be done with the rect pattern command)

I select Rect Pattern, select the chamfer feature, direction down, spacing with the values on the screenshot (q=2 dist=20) hit ok.... program returns error.???, the preview seems to look ok but I have no idea what I'm doing wrong, attached comes the file for you to play with.

Maybe there is another smarter way to do this I have not figured out, all the help I can get would be greatly appreciated.

Thanks in advance for all the help!

[HughesTooling]

Have you tried pattern faces instead?

Mark

[Anonymous]

just did, and it seems it wont allow me to pick the bottom chamfer face, just the upper one.

[HughesTooling · Accepted solution]

Try holding the Ctrl key down while selecting. Another option is delete the pattern then recreate, set type to Faces then click the chamfer in the timeline. Picking faces from the timeline doesn't seem to work while editing a pattern, only seems to work when the pattern is first created.

Mark

[Anonymous]

well, that does works, ... I guess it's a good workaround, but still a shame it doesn't work the way it is supposed to.

[HughesTooling]

I'm not sure chamfer is a good candidate for a feature pattern as it relies on selecting an edge. @jeff_strater  What do you think?

If you created the tongue as an extrude then chamfer you can both pattern as features as then you are patterning the edge that's chamfered as well.

Mark

[HughesTooling]

Just a bit better explanation.

Here I create the tongue as a separate extrude to the main sheet, chamfered then patterned both features.

Mark

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[jeff_strater]

yes, @HughesTooling is correct - the issue here is that you have chosen "Adjust" as the type of the feature pattern.  Not to expose too much "under the hood", but this type of pattern works by replicating the feature recipe itself, and recomputing each instance independently.  This is also why it is the slowest type of feature pattern.  In the case of just patterning a chamfer all by itself, it needs to find an edge to fillet.  It can't do so, since each edge is different.  As Mark says, though, if you pattern the chamfers with the tabs, that will work, because it's all one unit.

Alternatively, using Optimized or Face pattern will succeed, which I realize is a bit counter-intuitive.

[Anonymous]

Actually being in IT myself  I would love to know those under the hood details of how it works since it makes you better understand why the app is doing or not doing something could you please explain those 3 selections in more detail please?

Thanks in advance to both of you for all your help

[jeff_strater]

ok, here are the basics of the 3 (actually 4, but two are very similar) types of geometry pattern available:

1. Face Pattern and Feature Pattern (Optimized).  These two method use the same underlying kernel API - as its name implies, this method really patterns faces.  The only difference between Features/Optimized and Faces is the selection method.  Feature/Optimize allows you to select a feature in the timeline, and thereby select all the faces produced by that feature, where Face pattern requires you to select faces directly.  What this pattern does is to unstitch the selected faces, copy them, transform those faces, and attempt to stitch them back into the model.  So, you need to select a group of faces where this can be done.  That is, they have to land on existing model geometry, and have a clean intersection with that geometry.  Things like holes in a plane or bosses on a plane work well.
2. Feature/Identical pattern.  This method takes the selected features, and patterns the "tool body" of that set of features to each location, as a solid body.  At the end, one big Combine is done to join those patterned bodies into the target.  So, this method requires a set of features which have an identifiable tool body.  So, an Extrude, plus fillets on that extrude, plus a hole are a good example.  This one is slightly more expensive to compute, but, in theory, more robust
3. Feature/Adjust pattern.  This one, as I explained above, is where Fusion copies the Feature recipe, and re-executes it for each instance.  This allows you to do things like:  Pattern an extrude with To-Object termination to a face that changes over the pattern.  It is the most expensive to compute (since it requires the feature to be re-computed for each instance), but, in theory, should be the most reliable.  In actual fact, though, that is not true.  I've seen lots of cases where Adjust fails and Optimized succeeds.  Only use Adjust in cases where it is really needed.

hope this helps

[Anonymous]

thanks so much for that bit of information, I will analyze and test all those details to get a deeper understanding of what is going on.