Tricky stairs

I have a tricky set of stairs, I have modeled the base (I am not happy with how choppy it turned out) and now I must do the railings / sidewall.

I and a bit stumped on this one. the sidewall curve needs to angle and follow the stairs, as well, a railing on the right must follow the stairs.

I am generally good at problem solving but this one, in particular, has me stumped.

Does anyone have any suggestions? Thanks in advance!

Perhaps joining the upper parts of the bars with straight lines and then using a plugin like Fredo Spline to smooth the curve.

Your suggestion in conjunction with an extension called MAJ Stair got me closer.

You need to change the height of each bar so that they have a continuous slope.

Railings just emphasize generally awful design of this area

How would this be done in real life?

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It’s not uncommon to build the railing right on top of the tread nosings and then lift it the correct height from there. You could take the same approach within SketchUp itself when modeling.

Some of those winders look less than the 3" code minimum at the narrow end, but, hey, spiral stairs don’t have to meet that standard so why do winders? Don’t ask me.

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Haha, yeah… These steps are touchy Also, we weren’t sure which side of the stair to calculate the walkline since is curves in multiple directions. I dove into the stair codes pretty hard and it was unclear weather these would be considered spirals or winders.

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Talented stair craftsmen :yum: I just need a schematic at this stage to see if the clients like it and then we get serious.

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I guess the reason I was asking is because there is a definitive way to go about it by replicating how it would be done in real life by that craftsman.

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Yeah, you’re 100% right. Before I go and use up people’s time I just needed some kind of real world representation of it.

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If that is a stair you will be using a lot; I would definitely consider a more comfortable and user friendly design. Falls on stairways result in nasty injuries. those wedge steps are a huge risk to falls.

A curved stairs and railing will likely cost you more than adding some square footage to the house and use a simpler stair design. At least worth thinking about.

The backside of the stair construction hanging down in front of the doorway to the other room is not going to be a nice look at all. I think you could redesign and move a few parts there and come up with a nice two run stairs with a landing.


Howdy, I think I may have a quick solution for you using native SketchUp tools. First use the 2 point arc tool on the tops of your ballusters (not all of them, just the ones in the center of the treads) to create a three dimensional compound curve. Then use the follow me tool for the profile of the rail. Use the soften smooth feature to smooth the curves. Intersect with ballusters and shorten where needed. You may need to scale your model up 100% or more and then scale down after using the follow me to get a smoother rail. Cheers, Transom (1roughdraught)
Curved Stair Rail 1.skp (341.7 KB)

When you open the model you might turn on “Hidden Geometry” to see how I got the shape.

Thank you for this explanation!
I will continue to try different methods!
This is where I left it last week, I may try your rail method

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If you want to post the model up, I’ll play with it a bit to see if I can come up with anything.
Presumably, that first image you just included is what others were saying is a terrible view/design.

Ive had pretty good success with Fredo I think its radial bending or the TrueBend plugins. I modeled a straight stair with a Dynamic component I created (not sure that matters) and then “Bend it”. (BTW I could build those stairs)


Try to think about moving furnitures up and down your stair, unless you have another stair that allows for practical moving.

Stairs with abrupt changes of direction or curves make it tricky and even dangerous when moving large pieces of furniture like a sofa, for example.

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Thanks for the lookout!
We have indeed separate access to the upstairs.

That is how I solve these problems. I am a native tools fan. One suggestion would be to make a curved line on a horizontal plane that matches plan projection of your rail. Weld the segments together, then without selecting the line, grab one endpoint with the MOVE tool and move the point vertically to match the stair rise. That should give you a line with the proper slope and proper plan shape to use Follow me with your rail profile. Easier said than done, but with a bit of work you should get there with a smooth curve. All that said, you have a remarkably complicated problem here due the many variations in rise / run at the stair edges. You might want to consider a radical simplification of your stair, a suggestion from a grumpy old gray-haired architect who has witnessed more than one fiasco.


This is a tricky one because the plan of the tread layout informs the required handrail height because it should relate to the walking line. However the walking line also needs to meet regulations too so that the rise/going ratio also meets regs.
The walking line (according to British standard) for wider stairs is a set distance from the relevant string and for stairs narrower than 1m (from memory) is the centre of the stair.

I find it useful to draw a plan of the handrail centre line over the tread layout and then to extrude it up beyond the height of the stair.

Then replicate the tread height onto this extruded curved surface. This gives you a surface upon which you can draw a smooth centre line for the handrail that relates to the pitch line (pitch line being a line from nosing to nosing).

One caution when creating the handrail centre line is to remember that steeper parts need to be higher above the nosing line than any more level parts; when descending the handrail would be too low to hold otherwise.