AC21 - Double winder stairs

[Anonymous]

Goodmorning, I'm a new AC user and I don't find a solution to create a stair with a double winder (start and finish). Any suggestions? Thanks you a lot.

[Barry Kelly]

I have been playing with this as well as we do similar stairs quite a lot where the winders generate from the same point.
I know it is not a 'good' stair but it is one we use none the less.

It seems you just can't have the 'minimum riser offset' set to exactly 0 (zero) and have the stair flight width the exact size you want to model if you want to do a right angle stair.

You can set the 'minimum riser offset' to 0.1mm (or whatever that may equate to in imperial measurement).
The problem with this is you must then oversize your stair nodes by 0.1mm.
I find it is easier to map out the location of the nodes to snap to when placing the stair.
This may not suit when you have walls and slabs in place already - you will have to snap 0.1mm away from some of these points.
So if you want the stair to have 1000mm flights then you must set the nodes to allow for 1000.1mm

However you can set the 'minimum riser offset' to exactly 0mm so long as you set the flight with to the size you want - 0.1mm.
So if you want 1000mm flights set the width to 999.9mm.
This way you can use the exact geometry in your plan to place the stairs.

You can set the 'Working Units' to show 1 decimal place so you can see the correct figures.
It should all dimension up correctly as it will round back to the nearest mm and I am hoping the very small gap will not be notices in any 3D views or sections.

Barry.

[Barry Kelly]

It doesn't do the second (top) winders automatically but with a bit of manipulation that should be solvable.

Barry.

[Barry Kelly]

With a bit of node dragging the double winder can be achieved.
It seems to be very fussy about where you drag the nodes though.

Barry.

[alemanda]

I faced the same feeling to get my winder stair ...
The truth is the STAIRS are complex objects with so many rules, cases, parameters and exceptions to handle ... combine all the things in one tool only was a big effort.

[Barry Kelly]

The final result.
If you have tread and riser finishes you will get a false face on the structure.
But then with these zero spaced winders you probably wouldn't have treads with overhangs.

Barry.