Copy body does not work correctly when unrelated features are suppressed

[Julie_7]

I do not have time right now to create an example model, so I am going to explain it and see if that is enough.

I have a fairly simple design that uses parameters to generate various sizes of bodies and I use composition to create a number of body variations. One component has sketches and primitive bodies that are created from those sketches, some added features and some simple composition.

The component (component_B) that I am working with copies some of the primitive bodies, adds some features and composes them into the final bodies that I want to export for 3D printing. There are other components that depend on the primitives, but are completely independent of component_B.

The design was taking quite a long time (greater than five minutes) to recalculate when the parameters changed, so I tried to suppress all unrelated components hoping that would speed up calculation.

Surprisingly, the bodies that are copied to component_B from primitives are missing features. Specifically they are missing a pattern operation that occurs on the primitive before it is copied. If I make a new copy with the current parameters, it will be correct, but it will also fail to copy correctly when the parameters change again.

The timeline looks something like this.

create component Primitives, sketch, extrude body_1, add fillets, pattern feature,

suppressed (create component_A, do some things)

create component_B, copy body_1 to component_B, shell, add other features, combine with body_2

When I change the parameters, which among other things change the patterning of the feature of body_1 in the primitives, the copy of body_1 in component_B has no patterning applied to it at all. If I look at body_1 in Primitives it is correct and has the patterning applied.

- I don't understand why the patterning is not present on the copy of the body after parameters are changed?

- I don't understand why copying of a body is not editable, like other features in the timeline?

- I don't understand why calculation is so slow after changing parameters?

- I do know that Fusion 360 only uses a single thread which limits its speed.

- However, Fusion 360 does not use 100% of the single CPU during recalc

- The April 2023 update mentioned performance improvements. Is there anything that needs to be done by the user to enable these improvements? Do I need to delete a cache?

If the above is not clear enough, let me know and I will try to reproduce the issue with a simple example.

[TrippyLighting]

This is indeed hard to troubleshoot without having a model.

What did you pattern (bodies, components, features) and with which option ?

[nigel76FS8]

I've got exactly this same behaviour. Copying a feature doesn't pick up the "whole" body - sometimes!

I've found a workaround is to add another copy before the copy in the timeline, then suppress it! This causes the later copy(ies) to work correctly.

It is also 50/50 whether it will stay there when the model is loaded in, or whether it will need that suppressed copy unsuppressed and re-suppressed to make it reappear. Utterly not fit for purpose! CAD, especially parametric CAD, should not be stochastic! And it doesn't appear on Mesh exports if it's not visible in the CAD - that's how I spotted that the fairly concealed features were missing.

[TrippyLighting]

@nigel76FS8 @ Can you provide a model for examination

If there's a bug, there is not much that can be done to fix it without good data.

[Julie_7]

It is part of a significant design and I didn't want to provide it as a very confusing example. I was hoping it might sound familiar to someone. If I have time I will try to extract a working example.

[Julie_7]

I removed as much as possible from my design trying to leave only what illustrates the issue. I am going to list the steps to take to see it. I am going to upload the design in this initial state.

Module bottom with feet selected, and you can see the copy of it in the Bins component.

Now I make the bin bottom visible instead of the module bottom.

It looks the same. Now in the timeline I am going to suppress the steps that create the grid, shoe, shoe cutter. None of these have any interaction with the bins.

And after suppressing the group, which is named grid, and then forcing a re-compute with <ctrl>b the bin bottom has changed.

But the module bottom that it is a copy of has remained the same.

Unsuppressing the grid group will return the bin bottom to normal.

[TrippyLighting · Accepted solution]

While it looks like a bug (tagging @Phil.E), here is a workaround:

Create the new component before the Group that needs to be suppressed.

Instead of using the copy body feature you should get into the habit of using the boundary fill feature and then shell.

The boundary fill feature can be edited and allows re-selecting the body to be copied. The body copy-paste feature cannot be edited. 

[Julie_7]

Thanks TrippyLighting!

I am still a novice. I didn't know that the boundary fill existed. The reason I copied the body is that the documentation says that copying a component is an instance and changes affect the original. In contrast, copying a body allow the copy to be modified independently.

I have been looking at your design, and it illustrates one of the deficiencies of F360. If you edit a feature, which I often do, just so that I can see the parameters, you have no clue what the selections refer to. I wish it would add the name if it was a body, or do something to indicate what is selected. Even just clicking on the selection field to highlight the selection. Edit feature brings up a dialog that doesn't even tell me that the feature is a boundary fill.

I did read about and experiment with boundary fill. I can see how it would be a big help in capturing closed bodies from intersecting surfaces. I cannot understand why I would use it instead of just copy and paste the body that I want. It takes more steps, and it seems like it would involve more computation during recompute. I am more than happy to hear your reasoning and lean something new.

Another reason that I have been copying bodies is that in my full design, I create bodies that have some of the complexity in the main body, then I copy the body multiple times and make different changes to each copy. I am a software engineer, so I try to remove duplication as much as possible, using duplication, composition, etc.

The reason that the grid related features that I suppressed are before the bins component is that they are used in my complete design by a body in bins that I deleted for the example.

I can work around the bug, so it isn't stopping me from completing my design. I mostly posted to report it and to learn more about Fusion 360.

[Phil.E]

I'm not clear about the problem.

If features are suppressed, they aren't computed, and they aren't part of the model. Is the expectation that suppressed features would be copied as if they aren't suppressed? 

[nigel76FS8]

Phil, the issue is that sometimes the copy doesn't work properly, unless you toggle the suppression of an earlier copy you put in place to squash the bug.

[Julie_7]

I do expect suppressed features to not be computed. The suppressed features are not related, but their suppression causes a compute error in another part of the design.