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Bent section cuts

Grrr. another problem with archicad - the more you find out the more you find out how much more there is to learn...

I've been trying to get the section cuts in AC10 to bend. I'm working on a large site with buildings at different orientations and need to be able to cut a site section to display the front elevations of each of the buildings. The difference between orientations is only 10 degrees.

Whilst I have managed now to get sections to bend by fiddling around a bit, I cannot find a way to get the bend to the correct angle. Also the method in which I’ve been using the section line does not yield consistent results.

Can anyone help??
Mark Reid Rowland
Archicad 7.5 - 21 UKI
Sloth-like iMac i5
64Gb RAM
13 REPLIES 13

22 views and still no response... hmmm... not looking good. HELP!!
Mark Reid Rowland
Archicad 7.5 - 21 UKI
Sloth-like iMac i5
64Gb RAM

TomWaltz
Newcomer
I'm not aware of any way to bend a section marker. You can offset it, but not bend it.

I suspect you would need to make different markers for each angle.
Tom Waltz

Djordje
Contributor
TomWaltz wrote:
I'm not aware of any way to bend a section marker. You can offset it, but not bend it.

I suspect you would need to make different markers for each angle.
... and join them in the layouts if needed.

Elevation is a planar projection by definition; therefore it should not bend ...
Djordje

ArchiCAD since 4.55 ... 1995

Philip Caine
Newcomer
Forgive me if I am missing your point but surely it is illogical to try to introduce a bend in a section/elevation. It's like trying to look at a different point with each eye! Something like trying to introduce a fold in the middle of the view if it were imagined to be on a sheet of paper?
Philip Caine
Architectural Technologist
England
MacBook Pro 17”
ArchiCAD 19

owen
Newcomer
Djordje wrote:
Elevation is a planar projection by definition; therefore it should not bend ...
This is true but there are times when it would be very, very useful to be able to create a curved/bent elevation.

Such as drawing flattened/unrolled elevations of a curved curtain wall. Do this on just about every project I have worked on in the last few years and the fact these need to be drawn in 2D despite having a detailed 3D facade model frustrates me no end.
cheers,

Owen Sharp

Design Technology Manager
fjmt | francis-jones morehen thorp

iMac 27" i7 2.93Ghz | 32GB RAM | OS 10.10 | Since AC5

Link
Enthusiast
There is definitely no way to curve or even bend an SE. They can be segmented, but every segment must face the same way.

Hopefully bent sections won't be too far away.

Cheers,
Link.
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Philip Caine
Newcomer
owen wrote:
... it would be very, very useful to be able to create a curved/bent elevation.

Such as drawing flattened/unrolled elevations of a curved curtain wall....


Yes it would be a nice feature in theory BUT I cannot see it being practical for two reasons.

1. I get enough stupid questions from contractors without giving them "false" elevations to try and work with!

2. Unless the SE has a zero horizontal extent or at least a very very small one, then mathematically, it would be impossible because parts of the model would have to converge or diverge in some way.

It's fine to draw a schematic type elevation in 2D like this but it cannot work in true 3D
Philip Caine
Architectural Technologist
England
MacBook Pro 17”
ArchiCAD 19

owen
Newcomer
Philip wrote:
owen wrote:
... it would be very, very useful to be able to create a curved/bent elevation.

Such as drawing flattened/unrolled elevations of a curved curtain wall....


Yes it would be a nice feature in theory BUT I cannot see it being practical for two reasons.

1. I get enough stupid questions from contractors without giving them "false" elevations to try and work with!
The facade contractors I have worked with generate shop drawings of exactly what I am talking about - a single, flat (i.e fake) elevation of a curtain wall which curves in several places. It is the only way to clearly lay out all the panel types along a facade. We provide the same type of elevations in our tender sets (together with the traditional 'true' ones) as we have found it easier for everyone to understand just how it all fits together.
Philip wrote:
2. Unless the SE has a zero horizontal extent or at least a very very small one, then mathematically, it would be impossible because parts of the model would have to converge or diverge in some way.

It's fine to draw a schematic type elevation in 2D like this but it cannot work in true 3D
Whilst it is difficult to achieve I disagree that it can't work - its just a matter of programming. Yes there would need to be a line along which everything flattened is a true dimension. Things infront/behind that would be stretched/compressed to take account of the horizontal extent.

I'm sure there must be applications out there that can do this for manufacturing but i don't know what for sure. Perhaps CATIA? A machine has to know at some point what 'flat' shape a curved metal sheet actually is in order to cut it?
cheers,

Owen Sharp

Design Technology Manager
fjmt | francis-jones morehen thorp

iMac 27" i7 2.93Ghz | 32GB RAM | OS 10.10 | Since AC5

mikem oz
Newcomer
I'm sure there must be applications out there that can do this for manufacturing but i don't know what for sure. Perhaps CATIA? A machine has to know at some point what 'flat' shape a curved metal sheet actually is in order to cut it?
TouchCAD is one such program: http://www.touchcad.com/tc3features.html

Provides nurbs modeling of complex shapes with unfolding and reverse engineering capabilities. Very good for modeling boats, sails and the like. A very neat program.

Thanks for the comments - the bent section cut was for a presentation and was requested by someone more senior than me in the company and as I'm not much more than a CAD monkey I had to find out...

cheers!
Mark Reid Rowland
Archicad 7.5 - 21 UKI
Sloth-like iMac i5
64Gb RAM

um... just thought I should post a pic so people can see why a bent section might be useful... though I do agree that it's distorting the truth somewhat

See attached jpeg. (edited in paint )
Mark Reid Rowland
Archicad 7.5 - 21 UKI
Sloth-like iMac i5
64Gb RAM

Philip wrote:
owen wrote:
... it would be very, very useful to be able to create a curved/bent elevation.

Such as drawing flattened/unrolled elevations of a curved curtain wall....


Yes it would be a nice feature in theory BUT I cannot see it being practical for two reasons.

1. I get enough stupid questions from contractors without giving them "false" elevations to try and work with!

2. Unless the SE has a zero horizontal extent or at least a very very small one, then mathematically, it would be impossible because parts of the model would have to converge or diverge in some way.

It's fine to draw a schematic type elevation in 2D like this but it cannot work in true 3D
This isn't entirely true. In fact most other NURBS-based design programs (Rhino, Studiotools, CATIA etc) have an "unfold" function which essentially calculates and creates orthogonal unfurled single views of curved surfaces, which are necessary for CAD/CAM machining in engineering, parts manufacture, automotive and nautical design. The application of the function is obviously different, but the principle of how it works and the essential result is basically the same with the primary difference being that in those programs the algorithms that create those views are NURBS-based allowing for greater accuracy.

In Architecture, usually such functions are not necessary or available( since we don't usually design a great deal of curved and curvilinear surfaces to warrant the further development of such functions in our CAD programs) but given the relative difference in scale, of the difficulty involved and accuracy needed, there's no reason to suggest why a script function, in ArchiCAD for example, can't be written that would create, align and combine multiple section cut-lines along the desired path or curve and then to recombine all the views into one S/E window complete with lines demarcating where the single flat view folds at the various points or ends of each mini-Section cut-line to the next. It obviously sounds more complicated than it really is when you consider the fact that you can easily do it manually by creating all the necessary Sections/Elevations, aligning them as desired, creating the various views, delinking them and then copy-pasting the resulting 2D-views into one view or window. I seriously don't believe that creating such a script function is beyond the capabilities of Graphisoft developers.

The tricky part in application, obviously would be maintaining a live combined view which updates all related sections along with the model each time a change is made or the window is regenerated. We all know how (slow) AC can be with updating Sections and elevations, so now we would be talking of doing many at once. ( Here is where a desperately needed overhaul of the AC engine would come into play - and which is probably why we don't have such a function yet in ArchiCAD - because it just can't handle it at the moment.). The other caveat obviously is the fact that it would most likely be limited to a Zero-depth elevation (i.e. no background behind each mini-section), since a background in such a scenario is pointless and would needlessy make the PC choke on calulating those elements as well.

But it definitely can be done.....

Mark wrote:
um... just thought I should post a pic so people can see why a bent section might be useful... though I do agree that it's distorting the truth somewhat

See attached jpeg. (edited in paint )
I don't see why you can't manually do that in ArchiCAD using the method I described before.

If it's just for presentation, then all you need is three separate (but end-to-end) section views as per the straight portions of your view described below, and then generate the three views, delink them (if you wish) and then copy-paste and re-combine them into one new view, marking where each separate view starts and ends with a line.

We do that all the time in our office with angular or obtusely-aligned building facades and elevations.

As has already been pointed out, there is no automated function to do all this yet in ArchiCAD; hopefully in future versions (looks like a simple Macro-script to me; but then, so do Curved profiles in plan, so what do I know).

But then again, you'll be hard pressed to find any BIM or AEC CAD program that can do bent or curved section/elevation views.

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