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Tim Olson  
#1 Posted : Thursday, November 4, 2021 3:07:15 PM(UTC)
Tim Olson

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Spatial released an update to ACIS and added some new features that we are exploring...

One new feature is a Sheet Unfold.

But I'm not sure of the design context of unfolding a sheet(thin body) vs a solid sheet metal body.

So I thought I would check with the community on how useful this would be as design tool...

Attached link to video showing unfold...

https://youtu.be/9R234eIEf9I


Tim

Edited by user Thursday, November 4, 2021 3:11:34 PM(UTC)  | Reason: Not specified

Tim Olson
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murray  
#2 Posted : Thursday, November 4, 2021 10:18:07 PM(UTC)
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Isn't sheet/thin body unfold almost duplication of PowerPack's unroll? It's more formal, and PP's unroll still chokes on trimmed cylindrical sections, like fillets/blends with cutout features, if "sheet metal" is being pitched as a headline capability that wouldn't happen. Sheet metal also implies the same limits that TurboCAD's unbend enforces: only cylindrical sections with edges parallel to the bend axis. The formal definition of a sheet metal layout is that the bend material is the arc length at the neutral depth. Isn't that close to being doable with unroll now, if the enclosure is shelled to the neutral depth? TC users are perhaps a little blase because we've had unbend in Platinum since 2008, V15, although it was pretty rudimentary back then, which meant that we had to be imaginative to make it useful. This looks more immediately mature, but it comes down to cost: are you thinking about core capability, as a plug-in or as a specialised version? What's the cost impost going to be for each of those scenarios, and what sort of promotional effort is going to be needed to make it worthwhile to you to implement that feature?
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Tim Olson  
#3 Posted : Thursday, November 4, 2021 11:18:04 PM(UTC)
Tim Olson

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The Unroll Surface tool in PowerPack is quite different. That tool accepts ruled surfaces or meshes and internally creates triangular facets. It then rotates each connecting facet around the shared edge to a flattened state.

The ACIS version works with the actual definition of the sheet which would be an analytic or NURB definition. So the ACIS version is much more accurate especially if you are trying to preserve a circular cutout in a flattened state.

Nor does the facet based version unroll multiple, connected faces like tabs, bends, etc.

Since the ACIS version does not work with facets, I would likely combine the two together and change the name of Unroll to Unfold.

Attached is an example of an NURB object unfolded.

Unfold and Unbend are treated differently in ACIS tech documentation. As you mention, unbend is based upon a part with thickness and the netural depth. Unfold we would be using in the context of a sheet.


TurboCAD uses two methods for unbend. One a method that was developed internally some time ago. And a newer version using the ACIS UnBend tool. The updated version of the ACIS Unbend has some improvements which the TC dev team will be looking at.

At this point we are not sure how it will be exposed in PunchCAD. ACIS R2022 was just released Wed and we're checking out the new features and figuring out how they may apply to PunchCAD and TurboCAD Win. The first thing we actually looked at was replacing PHL-V5 in model to sheet with the newer CGM-HLR (hidden line remove) technology from CATIA.


Tim

Edited by user Thursday, November 4, 2021 11:33:03 PM(UTC)  | Reason: Not specified

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MPSchmied  
#4 Posted : Friday, November 5, 2021 3:00:59 AM(UTC)
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This will be extremely useful. Do not forget the K-Factor. Keep the good work. unfolding with other programs is for me a very big problem. The TurboCAD Unbend do not make a line where the bending should be.
With the right K-Factor and the lines for the bendings will it be a very good argument for a upgrade.

But please make the in stream zoom commands like in v.9 1162 first.
OS: Windows 10 | CPU: AMD Ryzen 7 2700 | RAM: 32 GB | Graphic: AMD Radeon RX Vega 56 | Shark FX 9 Build 1162 | Unit: mm
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murray  
#5 Posted : Friday, November 5, 2021 6:24:14 AM(UTC)
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@MPS a zero-thickness sheet tool won't do k-factor by definition. You'll have to work out neutral depth band offset the faces by that depth, which to my mind makes it very techy and accurate and it does look great as a single-action layout, but it isn't an eyes-closed tool. Recent TurboCAD does give bend area edges and centre, BTW, and it's always been possible to find them using TC's unfold face on adjacent planar areas.
@Tim, so even though PowerPack's triangle-based, and the Spatial stuff's NURBS-based, isn't the bend area width still fundamentally the arc length at neutral depth? The tricky stuff amounts to unwrapping trim curves for cutout features or corner punchouts, which I used to do by walking facets with TC's generic transform tool (align by 3 points), until TC development got it working within the unbend tool.

Edited by user Friday, November 5, 2021 6:25:12 AM(UTC)  | Reason: Not specified
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MPSchmied on 11/5/2021(UTC)
Tim Olson  
#6 Posted : Friday, November 5, 2021 8:53:50 AM(UTC)
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>>But please make the in stream zoom commands like in v.9 1162 first.

I saw some other posts regarding that issue.

Do you have some more detail/steps to repeat to help isolate further?

Tim


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Tim Olson  
#7 Posted : Friday, November 5, 2021 9:02:33 AM(UTC)
Tim Olson

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>>so even though PowerPack's triangle-based, and the Spatial stuff's NURBS-based, isn't the bend area width still fundamentally the arc length at neutral depth?

Yes, but only in the UnBend tool.

>> TC's generic transform tool (align by 3 points), until TC development got it working within the unbend tool.


Yes! That is what PowerPack is doing internally for UnFold/UnRoll. It creates facets, then does a 3-point rotation around the facet edge. So with V14 we will update UnRoll to Unfold, use the new ACIS procedure for Unfold on everything but mesh data.

I grabbed a snapshot of the ACIS docs to further clarify how it is calculated for UnBend. The K-Factor is then the ratio of the neutral axis to the material thickness

Tim

Edited by user Friday, November 5, 2021 9:09:44 AM(UTC)  | Reason: Not specified

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thanks 2 users thanked Tim Olson for this useful post.
MPSchmied on 11/5/2021(UTC), memphisjed on 11/9/2021(UTC)
UGMENTALCASE  
#8 Posted : Saturday, November 6, 2021 6:46:27 AM(UTC)
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I normally offset the surface to make the neutral plane, its near enough. I've used it and proved it out on a few projects.
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