Who fancy a challenge?

michał_1

Recreate this in Onshape, prove that Onshape is better than Solidworks or Fusion.


And here is an dwg: https://cad.onshape.com/documents/4b5c7480fa796f96d9c9f542/w/47d8242ba97f69df693a4558/e/7f1d1fefce208d9facb937f4

NeilCooke

Ask me again tomorrow.

konstantin_shiriazdanov

here is a simplified part with cam geometry
https://cad.onshape.com/documents/39369c7fe89d343a835363dc/w/4c259cbc4e31028ea24d5754/e/b0228ac5cf7949b4a73c17a8

michał_1

Nice job. I must admit you git me surprised.

philip_thomas

@NeilCooke - you are such a cheat!!!!!!
Lets see who has it ready to go when we push

michael_bromley

Sounds like we have some nifty new features coming down the pipe 

philip_thomas

Ok, my bravado aside, this is really hard (even with some new functionality ) 
I have a feeling it won't be me solving this!
This is why we have servo driven mechanisms and not cams!

michał_1

Ok, so I have my way, link to model is the same as for dwg in posts above.

There is no single FS just Sheet Metal for "wrap". But That wasn't the point of the challenge.
I was working on this model for F360 forum (https://forums.autodesk.com/t5/fusion-360-design-validate/solid-model-from-wrapped-geometry/td-p/8969749) and this was a nice case to show how SM can help to bend if you know what K factor means actually. 
I was hoping that sweep will do the slot... but even with rails and guide surfaces, it was not enough. Eventually, I've ended with loft approximating the right shape (which wasn't right at all, and I knew that just after posting on F360 forum and before posting here).
This approximation with loft is something I do quite often when I have complex "rule" driven surface.
I was sure that this model is such case and I was wondering what Onshape can offer (some FS)?
It turns out that I was too hooked on a sweep and didn't investigate enough the geometry itself.
When @konstantin_shiriazdanov posted his response, I immediately went to model and edited Cylinder sweep custom feature, and saw this:

I swear I could hear a CLICK in my head and a voice: thicken and fillet you DUMBASS.

So ok, this model couldn't challenge anyone... but still I do sometimes lacking more control over sweep/loft in certain cases.
When I find one I will try to poke the sleeping bear again.

konstantin_shiriazdanov

I should say that Cylinder sweep is a bit smarter than just filleting the ends of the thickened surface,  if it was so the thing like this would be pretty hard to model. Instead it subtracts cylinders along sharp linear edges,

michał_1

I was rather referring to the nature of that specific geometry, not to your FS.
I don't doubt it's well thought out, you've proved yourself many times here Konstantin.

konstantin_shiriazdanov

Thanks, anyway hope to see here in OS a natural Solid body sweep sooner or later

owen_sparks

Hi.

The geometry challenge is interesting, but what does the actual part do?

Cheers, Owen S.

michał_1

Who knows, some sort of locking? Don't ask me, I'm not an engineer.

owen_sparks

michał_1 said:

Who knows, some sort of locking? Don't ask me, I'm not an engineer.

Ah, sorry, I presumed that was your desk in the photo!  I was hoping it was a bit of a tank that we could follow along with and build one bit each month...

michał_1

True, whatever is the purpose of that part, it can take the load.

NeilCooke

@michał_1- I like your idea of using sheet metal.

Here is my take using the new "Wrap" feature. I still had to use Thicken to get the parallel side walls, so some of the fillets are a bit wonky and there's a small matter of non-manifold geometry at the bottom of the slot requiring a minor dimension tweak (within tolerance of course). 28 features - BOOM!

We like a good modeling challenge, so if you find any more please post!

https://cad.onshape.com/documents/6e98b5b5515c5c31ee98896f/w/cd7a7f83561fcde67b09c827/e/c73b1f5a5837953dcd0b1b0b

michał_1

A nice tool, very handy. The model is also nice, except it is not 67deg. I blame the drawing for that. That "developed" view looks like hand-drawn, not derived from a part.

NeilCooke

Huh, you're right - didn't even think of checking. Fixing the angle caused the Thicken to crease so I had to do a little remedial surfacing work on the highlighted face. At least the fillets look good now.

michał_1

I don't think it's still right, the issue is that flat drawing of a slot has a distance of 2.5in, between straight sections (between centre lines to be specific). If the angle is 67 deg with an arc length of 2.5 in, then this must be developed from a cylinder of a diameter = ((360*2.5)/(67*PI)) ≈ 4.276 in
That's why I think that whole view is "faked" because it doesn't refer to any finite value for radius/diameter (of course maybe this value is close to some common imperial units value? Don't know that system at all).

NeilCooke

It does now measure 67˚ - I had to use a calculator, but the offset between centerlines is now 2.667627 inches (wrapped around a 4 9/16 inch cylinder). Inches are horrible!

michał_1

In the drawing, distance is 1.249 (scale 1:2), but if you redraw it you'll have exact 2.5 (scale 1:1). If you go with different radius it will distort "fillets" and the angle of a slope.

NeilCooke

Correct, keeping the radii on the slot and making it wrap 67˚ (outside radius is detailed on Partial Section B-B) will distort the angle of the slot which I'm guessing is the least important dimension. Anyway, I think we can agree it's a bad drawing.

ChuckKey

@konstantin_shiriazdanov

Thanks for pointing this discussion out

The Trial Wrap folder here:

https://cad.onshape.com/documents/b14e8bd3a07bc75e67dcf6a9/w/f93a924ad45231ffcd3acb05/e/5bf07ed42da6b25483620c20

shows my own little experiment using this method of wrapping, lofting a radial surface, and thickening it. A bit clumsy, but it does the job.

A couple of points:

I am not sure how I would have found your cylinder sweep feature script, even if It had occured to me to look. Is the average idiot in a hurry missing out on what is available?

I tried to wrap a line and a composite curve, for the centreline of the slot, but it seems only a sketch surface can be wrapped, so a bogus sketch surface is required.

There seems to be some slight imperfection in the calculations as I was left with a couple of little artefacts that had to be deleted. Sure, I could have got round that, but I thought them better left for inspection.

@NeilCooke - this tidies up a discussion about face-cams we had in December 2015!