Press/Pull bug

[etfrench]

Using Press/Pull to change the diameter of this worm gear results in Fusion 360 to grind to a halt for what seems like hours.  The root cause is the arbitrary number entered in the distance field.  This particular worm gear has an initial diameter of  25.796875 mm and the desired diameter is 27 mm.  Setting the Distance to more than double the current size causes a lot of unnecessary calculating.  Once Fusion 360 returns from its holiday, calculating the 27 mm distance takes seconds.

[Phil.E]

Please post the gear model.

[etfrench]

Here's the file.  It was originally created in Inventor.

[chrisplyler]

If you push/pull that face, Fusion has to try to keep the "diameter" of the torus (of the max thread and the min thread) the same, right? And the area of the pulled face has to decrease as it comes up around the torus, right? I'm guessing it gets stumped as you try to pass the midpoint of the torus and it has to try figuring out how the face starts getting larger again. A complete guess, but it makes sense in my mind, as I assume the algorithms responsible for figuring that all out aren't complex enough to handle it well.

Or heck, it might start getting confused before that "halfway" point, if the max diameter of the threads exceeds the width of the gear, it's going to hang up as those max diameter faces cease to exist as the gear face is pulled outwards.

[etfrench]

It takes around 20 minutes for Fusion 360 to decide that it can't Press Pull the arbitrarily large distance it populates the dialog distance setting.  Once it fails, setting the distance to the desired value takes a few seconds for it to complete.

The same task on a 144 tooth gear fails quickly for any value entered.  Splitting the gear into one tooth, then Press Pull works.

[TrippyLighting]

I am not sure I would classify this as a bug.

It isn't a recent occurrence but many years old and appears in a number of forms.

[etfrench]

I disagree.  Taking 20 minutes for a totally unnecessary calculation is a class 1 bug.

[chrisplyler]

Yup.

The field should not auto-populate, and the attempt to solve/preview should be based on a user input/trigger instead of constantly attempting to solve/preview DURING input. Or at least there should be a ten second time-out built into the function or something. Anything that takes longer then ten seconds to solve is likely to be an invalid unworkable input.

[Phil.E]

This is pretty strange.

First some definitions:

Press/Pull: this is a multi-tool for Fusion. Based on context it will fire another command, such as extrude, offset faces, or fillet.

If it fires offset faces, in direct mode, it will show you the current radius value. This is because in history free models, values like the current radius mean a lot more than in parametric models where values like that are stored in the parametric table.

Strangely enough:

I just tested the original model and got some strange results.

1. Press/Pull only hung twice. After that it worked perfectly over and over again.

2. Press/Pull only tries to show the current radius value each time it does not hang. 

3. I had no problem changing the value by a couple mm. 

Bottom line, it all seems to be working as design. I cannot repeat the hang, therefore I have nothing to report to development for fixing. Strange case, but elusive bug.

[etfrench]

It seems the pre-populated value can be somewhat close at times and then not.  The bug is that it appears to be trying to calculate the results instead of waiting for the OK button to be pressed.  The other possibility is it is failing to correctly calculate the pre-populated value.  When it hangs, the pre-populated value as about double the actual value.

[Phil.E]

It should be precisely the radius. There is no "close" in the code. That means something is influencing the field to have a different value, i.e. dragging the arrow (accidentally or by some unknown bug).

If you can reproduce it please share. I'm happy to track this down. I was hoping to do so when I tested this morning. 😞

[laughingcreek]

@Phil.E -I have noticed similar issues with offset faces many times, both with the time line on and in DM.  Here is a stripped down repeatable example in DM.  It seems to manifest in other ways also.  Once I could of sworn it was pre-populating with a value I had entered when doing an offset face on a different object.  haven't repeated that one yet. 

[TrippyLighting]

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@laughingcreek wrote:

@Phil.E -I have noticed similar issues with offset faces many times, ...

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Yep, same here! Many, many times!

[etfrench]

While this file doesn't have the excessive hang time, it does show the distance field is being populated with the wrong value for Press/Pulling a cylinder.  It is using the diameter of the cylinder instead of the radius.  The attached file was created in Inventor, then imported into Fusion 360.  Chamfers were deleted prior to the Press/Pull command.

[laughingcreek]

slightly different results using the file @etfrench  just uploaded.  In this case offset faces pre-populates with the correct offset the first time (30.559).  but When I cancel that and go do a push pull unrelated to that object (using a value of 7 in this case), and then go back and try to do the original offset faces, it pre-populates with the radius plus the value used in the previous command (30.559 + 7 = 37.559)

see screen cast.

and now insert screen cast is messed up on the forum, so here is a link-

edit: wrong link.  here's the correct one-

https://knowledge.autodesk.com/community/screencast/a8f03dbc-894a-42d9-afe0-d33b7cc82fc0

[Phil.E]

@laughingcreek Thanks for the clue.

Here is the bug:

• In DM models, such as the gear, Fusion defaults Press Pull to the existing value of the radius. This gives you the "known" starting place from which to make an offset.
• In DM models, the final value is remembered and for some reason added to the next selection.

What it should do: Just give you the "starting size" each time you use press/pull (offset) in non-parametric modeling.

Workaround: Restart Fusion after keying in any offset value to avoid it being applied to the next DM offset.

[TrippyLighting]

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@laughingcreek wrote:

... and now insert screen cast is messed up on the forum, so here is a link ..

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Use the embed method. Amongst all the screwups with the webs site this has not failed me a single time and I've embedded hundreds of screencast this way.

[Anonymous]

Hopefully that means its likely to be fixed someday soon? (Because restarting Fusion isnt really a workaround)

When you have a pre-populated value from the last press-pull the dialog just opens up and starts calculating it without any input from user. Even if it is the "last value" which is sometimes helpful, that should still require some confirmation or [enter] action - otherwise if your previous extrusion was 25mm and you're trying extrude 0.1mm on something completely different, then you're in hell waiting for Fusion to calculate something that you know will end in an error.

Also - please note similar issue occurs in Scaling function - calculation begins literally as one is entering the value - e.g. if you want to scale up to 2/3, the function begins re-scaling to 2 while a user is still entering the "/3"

[Phil.E]

Hi,

These are two different issues. Scaling is just calculating as soon as you enter a number. It doesn't remember anything. Workaround: in parametric models create a named parameter called Scale and use the parameter name. It won't compute anything until you press OK. If you have a model that will hang for a long time when using scale with a value like 2/3 please share it with me, I'm happy to log a bug report showing how this impacts you based on your model and workflow.

Regarding press-pull (offset), to this day I cannot reproduce this reliably. (it is reproducible but requires a specific set of steps and that depends on your workflow). Do you have a model and some steps I can take to log another bug for it? Real customer data is valuable for explaining the impact of this behavior.

Workaround: Try the "offset faces", "extrude", and "fillet" commands. These are the commands that Press-Pull is actually doing, depending on what you selected. Let me know if that works for you.

[laughingcreek]

could you not reproduce it with the file already supplied?