!Restored: Flaw in stair logic

[Anonymous]

The problems with the stair tool stem from a flaw in the logic. The stairs are being defined by where the riser is rather than where the front edge of the stair tread is.

In this post I've attached an image showing a stair that does not have a nosing overhang:
- the 3D matches the 2D; and
- the handrail is the correct height above the nosing of the stair (as stipulated by regulatory requirements).

In the subsequent post I will attach an image of the same stair with a 30 nosing overhang:
- the 3D no longer matches the 2D; and
- the handrail is no longer the correct height above the stair nosing.

These problems occur because the 3D of the stair is being generated by the outside face of the riser rather than the front edge of the tread. The nosing overhang is being added to the front edge of the tread instead of at the back where it should be, with the riser face moving back by the distance of the nosing overhang.

In the real world stairs are set out by their treads, not the risers, and the locations of all of the other elements of the stair is determined relative to where the treads are located.

I'm really surprised that a program as mature as Archicad 11 contains such a fundamental flaw in its logic. It is not reassuring.

[Anonymous]

In this image of the same stair with a nosing overhang. Note how the additional tread width has been added in front of the riser rather than at the rear of the tread with the riser moved backwards.

This behaviour must create havoc on winder stairs with the consequence being that they are not modelled correctly.

[Anonymous]

To demonstrate how absurd this logic is I have attached an image with the nosing overhang increased to the maximum possible (127 mm / 5"):
- the 2D is now nothing like the 3D; and
- the handrail height is a long way short of the required height above the stair nosing

This logic flaw could quite easily lead to the built stairs being non compliant with the result being the Architect being sued to fix the problem.

Please fix it.

[TomWaltz]

mikem wrote:
I'm really surprised that a program as mature as Archicad 11 contains such a fundamental flaw in its logic. It is not reassuring.

The Stair Tool is one of the least useful and most highly flawed tools in Archicad. It has seen no real improvement in years and is something Revit resellers love to proclaim.

You're right, it's absurd that the Stair Tool is still this bad.

[Erich]

mikem wrote:
This logic flaw could quite easily lead to the built stairs being non compliant with the result being the Architect being sued to fix the problem.

IMHO, this is hyperbole, any architect that fails to check their work and makes such an error should deal with the consequences.

While I too would love to see an improved stair tool, we should not begin to imagine that the software is meant to take the place of thought and consideration on our part. Thankfully we are the architects not the software.

[Bricklyne Clarence]

Erich wrote:
IMHO, this is hyperbole, any architect that fails to check their work and makes such an error should deal with the consequences.

While I too would love to see an improved stair tool, we should not begin to imagine that the software is meant to take the place of thought and consideration on our part. Thankfully we are the architects not the software.

IMHO, this (what you said above, specifically) is absurd.

It's somewhat akin to implying that if I buy a car whose braking system wiring keeps failing because of poor or loose connections, then in the event of an accident caused by brakes failing, I should be the one to blame for not checking that everything was in working order before I drove off - despite the fact that the manufacturer assured me that his product works fine. That's ridiculous!

When car manufacturers discover errors like this in their products, they recall every single one of them and fix the problem as soon as it becomes apparent. It's called taking professional responsibility.
Thankfully GS don't have to recall every license that they sell, but only have to issue a patch or hotfix to resolve the issue. Which begs the question why such an error would still be there after so many versions and so many hotfixes over the years with all the complaints on this particular tool.

And nobody is seriously suggesting "that the software is meant to take the place of thought and consideration on our part" as you said. But the logical and reasonable expectation is that the software will work well and as expected.

Of course the architect is still responsible for checking the accuracy and veracity of the drawings and documents he produces, but if GS's pitch is that ArchiCAD will save him the time of having to do all this himself, along with coordination errors, through an automated and parametrically driven software process, then what's the point if the architect still has to go through all the drawings again as if a human had drawn them just to make sure that the oh-so-accurate computer software didn't make a logical error?

If there's a feature that Graphisoft can't get to work properly then it shouldn't be there to begin with.
You don't place the blame or the responsibility for this kind of error on the customer especially if the error is not so apparent to all, without considerable testing and especially when you sold them on the fact that your software works properly and most especially if the error is part of a buggy tool for which the users have been clamoring an immediate upgrade and fix going almost 5 versions back.

[Anonymous]

The fact remains that the logic is flawed and because of this even with a small nosing overhang:
- the handrails are not at the height the dialog box says they are.
- the 3D is showing the treads in a different location to the 2D.

That is not correct and will never be correct.

[Erich]

Bricklyne,

I am not saying that the software issues are not a problem. Indeed, I agree that stairs are laid out from the nose of the tread. The failure of this tool to respect such practice IS problematic. Often in our designs we have stairs that cause us to have to go to great lengths to make work as the codes require and that the tools provided make that harder is an issue.

My comment was referring to the idea that such a flaw could lead to the stairs being built wrong and result in the architect being sued. Regardless of the tool used be it pencil, CAD or Virtual Building or even the point and shout method, it remains the responsibility of the architect to be certain that what they draw works. If I ever caught anyone working for me not checking something critical like this, I would be furious. Presumably, there are stair details to go with the pretty pictures and in those details such a discrepancy would be caught, at least that is the hope.

While I think the flaws of the program should be pointed out and, with any luck, be fixed. Engaging in hyperbole is not productive. And yes, if there's a feature that Graphisoft can't get to work properly then it shouldn't be there to begin with. That comment should be followed with the idea that stairs are a critical part of architectural practice and need to be in the program and need to work.

As for the car analogy, if it was your job to make sure the brakes worked and they subsequently fail then, yes, you are responsible.

[Anonymous]

The important thing is to get this fixed. And it has to be fixed in Archicad 12.

Erich, just as we have a responsibility to check things, it is not unreasonable to expect that Graphisoft will check the different program parts to ensure that they are correct. It is basic Quality Assurance.

I find it hard to believe that this basic logic flaw hasn't been picked up before now, and therefore fixed. Why hasn't it been? Are there other isues like this lurking within Archicad?

[Erich]

Mike,

Are there other issues...you betcha! It all depends on what you want to do and how you want to show it. The stairs have long been a sore point for users. You have picked up on one of many complaints. If you haven't done so already, vote here on that some of these issues are fixed. (Just one of many stair wish list items)

http://archicad-talk.graphisoft.com/viewtopic.php?t=1656&highlight=stairs

But don't hold your breath of it being fixed in 12.