Disturbing Phenomenon

[William_Dec_45]

While following along an AutoDesk YouTube tutorial, I run into this problem: I combined the male and female with a combine/cut. When turning off the male, the female has a strange sliver hanging off the joint. I don't want to misquote anyone, but I believe it was suggested to merely delete those edges. That seems too hackish for such a fine bit of software. And besides, I haven't found any way to delete them. What's going on here? Any help will be greatly appreciated.

[TrippyLighting]

Those "slivers" are not the result of some flaw in the software but are a result of a straight extrusion Into a circular structure. It is logical that they are there and if you don't want them then deleting the edge might do that, but would not be my preferred way to deal with that situation. 

 

Can you provide a link to that tutorial ?

[William_Dec_45]

Yes. Here is the link. If you advance to 55:45, you'll get to the meat of it.

With regard to straight-entering curvature, know this-- he did use revolve to make the male feature, he didn't just extrude straight out. I think that's what you were suggesting. Not sure, still a total noob here. In the file I sent up, I used press-pull which also extruded in a curve.

https://www.youtube.com/watch?v=ZBRiefMZTgQ&t=221s&ab_channel=AutodeskFusion360

[TrippyLighting]

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@William_Dec_45 wrote:

Yes. Here is the link. If you advance to 55:45, you'll get to the meat of it.

With regard to straight-entering curvature, know this-- he did use revolve to make the male feature, he didn't just extrude straight out. I think that's what you were suggesting. Not sure, still a total noob here. In the file I sent up, I used press-pull which also extruded in a curve.

https://www.youtube.com/watch?v=ZBRiefMZTgQ&t=221s&ab_channel=AutodeskFusion360

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I know how the design and every single feature in it are created. I provided a screenshot that should have eliminated any doubt what I was referring to! Basic geometry, really 😉

[William_Dec_45]

I didn't mean to suggest that you didn't understand. Clearly, you do. I've
seen your credentials. I just wanted you to know that the tutorial didn't
suggest a straight extrude when a curve was needed.

[TrippyLighting]

I think the technique to eliminate the sliver is an unneeded shortcut and very easy to avoid.

The extrude for the recess is based on this sketch.

If Brad simply had used a little more sketch work and extruded a complete half profile then that sliver would not have been created.

[William_Dec_45]

I'm not sure if this is what you mean, but-- after using Brad's shell
technique, I tried making the male extrusion by using the offset command
and then extruding half of it out. I get the 'artifact' either way. I've
had great success using the combine/cut technique on simple cube-shaped
objects. This revolved object is the first time I've seen it fail. Again--
I'm very new at this.

[rushabhthakkar_910]

I have tried removing those... See if it help...

[William_Dec_45]

Thank you. I see that you have removed the unwanted material, but I'm more interested in how to avoid it in the first place. Another observation that I've made is that the male and female are not exactly the same thickness. It seems to me that the difference could be huge if the ultimate manufactured product needed to be water-tight. 

[William_Dec_45]

Thank you. But I don't understand the solution.

[TheCADWhisperer]

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@William_Dec_45 wrote:

I used press-pull which also extruded in a curve.

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No, actually it didn't.

You can check this in several ways - in image I attempt to create a new sketch.

Can only create new sketches on Planar faces.

[TheCADWhisperer]

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@William_Dec_45 wrote:

 Another observation that I've made is that the male and female are not exactly the same thickness. It seems to me that the difference could be huge if the ultimate manufactured product needed to be water-tight. 

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You did not model correctly, and actually, we can't make perfect parts in the real world.  There is tolerance associated with each and every feature dimension.  Appropriate clearance should be included in the geometry such that the max material condition will still fit together.

[TrippyLighting]

@TheCADWhisperer One could argue for a basic modeling tutorial that would be OK. If you want to analyze this for manufacture then there are a number of other issues associated with this model. No drafts, undercuts etc.

[TheCADWhisperer]

Yep.

For something like this learning exercise it would probably be best for the OP to follow the instructions of the presenter explicitly.  Brad alluded to the issue, but the OP should become familiar with the software before going off on tangents (pun intended).

Although in the classroom I like to go off on tangents and show incorrect techniques.  Little harder to do that in a YouTube video where the explicit instructions cannot be followed.  Imagine the confusion if several alternatives were presented to a raw beginner.

Having said that, person in >>this thread<< has been using Fusion for 4 years and still can't create threads (pun intended) because they haven't learned to fully define sketches and are creating conics rather than cylindrical features.

I've always found it harder to re-train  than to take a raw beginner through the steps.

[TrippyLighting]

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@TheCADWhisperer wrote:

I've always found it harder to re-train  than to take a raw beginner through the steps.

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I think re-training is going to be the prevalent mode of teaching in this YouTube age.

[William_Dec_45]

"For something like this learning exercise it would probably be best for the OP to follow the instructions of the presenter explicitly. Brad alluded to the issue, but the OP should become familiar with the software before going off on tangents..."

I can't imagine anyone thinking they could learn while not following a tutorial explicitly. I did the exercise precisely as Brad taught it. I used his shell method to make the male projections, I used the offset method he alluded to as an alternative, and I used the press/pull only because of his demonstration showing how it would extrude concentrically while the extrude command would pull in a straight line.

The file I posted for your advice was not my declaring it okay to vary from Brad's tutorial (by using press/pull). It just happened to be my most recent attempt at the time and I was looking for answers as to how to avoid the unwanted result which Brad, himself, addressed.

I considered the possibility that you guys knew of something he should or shouldn't have done. He's been criticized before as being somewhat unorthodox (not my words, but those on this forum).

As to the OP becoming familiar with the software... I've done little else over the past three or four months! If asking questions gives me away as someone who wants to be taken by the hand rather than work to learn, I'll refrain from asking.

I remain appreciative for those times in the past where you've been kind enough to show me details that weren't clear to me after watching various tutorials and leaving me in need of retraining.

[William_Dec_45]

"For something like this learning exercise it would probably be best for the OP to follow the instructions of the presenter explicitly. Brad alluded to the issue, but the OP should become familiar with the software before going off on tangents..."

I can't imagine anyone thinking they could learn while not following a tutorial explicitly. I did the exercise precisely as Brad taught it. I used his shell method to make the male projections, I used the offset method he alluded to as an alternative, and I used the press/pull only because of his demonstration showing how it would extrude concentrically while the extrude command would pull in a straight line.

The file I posted for your advice was not my declaring it okay to vary from Brad's tutorial (by using press/pull). It just happened to be my most recent attempt at the time and I was looking for answers as to how to avoid the unwanted result which Brad, himself, addressed.

I considered the possibility that you guys knew of something he should or shouldn't have done. He's been criticized before as being somewhat unorthodox (not my words, but those on this forum).

As to the OP becoming familiar with the software... I've done little else over the past three or four months! If asking questions gives me away as someone who wants to be taken by the hand rather than work to learn, I'll refrain from asking.

I remain appreciative for those times in the past where you've been kind enough to show me details that weren't clear to me after watching various tutorials and leaving me in need of retraining.

[davebYYPCU · Accepted solution]

I don't think anyone is trying to discourage you, and please keep asking until you get the answer, 

bear in mind it is hard to convey meaning with text.

That said, Brad is the first to say, may not be the right or wrong way, just the way I did it.  He ended up after many experiments going this way, knowing about the slivers, we all compromise at times.

The sliver question, who knows why,

(Fusion internal tolerance? doubt it is user error because it happens to all who do it)

should not happen, but it did.  Brad was stumped on that as well. 

Trippy has suggested an alternate workflow, is more work to avoid the sliver, with a large diversion from the tutorial.

There are many ways to get the same result in Fusion.

[TrippyLighting]

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@William_Dec_45 wrote:

I considered the possibility that you guys knew of something he should or shouldn't have done. He's been criticized before as being somewhat unorthodox (not my words, but those on this forum).

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I would not call the technique Brad used "unorthodox". It's sloppy!

Ive made over 800 screencasts on this Forum and a good number of YouTube tutorials and sometimes you need to use a shortcut to get the video completed in a reasonable amount of time.

The danger, is of course that in this day and age these techniques get picked up by many people people and add to a fairly widespread proliferation of bad techniques and ill conceived concepts.

Asking questions if something does not seem quite kosher os perfectly fine, however, my suggestion for your next question would be NOT to assume the the software is at fault. While that does happen, 95% of the people who think the software is at fault simply don'y have the subject matter expertise  to make that assessment.

[TrippyLighting]

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@davebYYPCU wrote:

The sliver question, who knows why,

If you actually look at the file it'll take you 30 seconds to figure out what that sliver is there, it's that simple!