topic Re: Special railing in Modeling

Special railing

Anonymous — Tue, 09 May 2023 13:44:59 GMT

Hello everyone!

A little bit of context before I start:
I work for a company as a designer that makes staircases only with a special technology.
Currently we are using ArchiCAD 16 for the designing process, however it takes a long time to "fix" 3D models created by archiCAD because of our technology. Now days, we are required to make ~10 layouts, sections and models a day. We're nowhere near using ArchiCAD to its full potential.
I've downloaded the demo version of ArchiCAD 24 to test out it's capabilities in stair making. So far I'm happy with it, but the biggest help for us would be a custom railing.
A quick word about the technology, just to make sure everyone understands what my goal is.
We use gypsium as shutter, and fill it up with concrete. 1 cm gypsium+3 cm concrete+1 cm gypsium = 5 cm total width.
To make the structure rigid, if we can't connect to a wall, we use a type of stringer beam.
I've attached some pictures of this that I really quickly threw together. (Ignore my bad geometry in the middle, I tried to make it as fast as possible).

As you can see its a stringer beam upside down. Making it with the mesh tool takes time. Setting up normal railings and using Solid Elements tool is really painful when it comes to a 5 cm stairwell. (90% of our staircases).
My goal would be to be able to place this with the Rail tool, and make the bottom part of it follow the steps, as its rising up.
I just don't know where to start. Its a very simple geometry, so I think it isn't as complicated as "normal" railings.
Could anyone point me in the right direction?

Re: Special railing

Barry Kelly — Fri, 05 Mar 2021 06:43:23 GMT

I don't think you will ever do it with the railing tool as the railing will follow the slope of the stair and not each step.

However the stair has an option to show the stringers and they can be either sloping or stepped.
You need a combination of both - stepped on the bottom and sloping on top which is not possible.
Maybe a new stringer object could be scripted - but that looks quite difficult if it is possible at all.

You can achieve this result with a Solid Element Operation though.
Create the stair you want with the stringer only option with the straight stringer and turn on the treads and risers.
Set the top of the stringer to the height you want and make the depth quite large so it extends below the stair.
Now duplicate this stair and turn the treads and risers off and change the stringer to the stepped option.
Set the top height offset to zero so it is level with what would be the top of the treads - unfortunately you can not set a negative height.
Now lower this stepped copy so the top of the steps is at the level you want the stepped stringer base to be.
Use this as a Solid Element Operator on the other stair (the target) with subtract and downward extrusion.
Hide that operator in a layer that you can turn off.

It might not be perfect but play around with the sizes (depths of the stringers and you might get it a bit better than this quick attempt.

I am not saying it will be perfect but it will get yo close.
Easier than working with morphs from the beginning.

You could also do the same thing with 3 stairs.
One with just treads and risers - no stringers.
2 stairs with just the different stringers (no treads or risers).
Do the same SEO on the stairs with just the stringers and then convert to a morph for final editing.
Then add this to the stair with just the treads and risers.

Barry.

Re: Special railing

Anonymous — Fri, 05 Mar 2021 16:43:05 GMT

Thank you for your answer.

I've tried it out, and its quite easy, and much quicker to do. Especially now that I found out, you can simply pull end points of the sloped beam in edit view, to get closer to my desired geometry in the middle.

Re: Special railing

Hmooslechner — Tue, 09 Mar 2021 17:19:43 GMT

An other possible solution:

https://www.youtube.com/watch?v=eUbBQ8a7Uok