I’m trying to find out if it is possible to create a smooth solid handrail for a spiral staircase with SketchUp’s native tools? Students aren’t allowed to use extensions. Any help and suggestions would be greatly appreciated. I’ve attached the stairs that I’m trying to work on.
SPIRAL STAIRS.skp (190.1 KB)
Many thanks.
The fact you are using components gives you the opportunity to make a simple structure to follow.
Here’s a starting point idea.
Thank you for the suggestion @Box . I’ve tried that and that makes sense. I’m after creating something like the image attached. If you have any suggestions, that would be greatly appreciated.
I would make the stairs part of a circle rather than flat sided and extrude the walls.
Here I have just added an arc, but you could do much better with a modified step so that they flow together.
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Thanks very much. I appreciate your help. Will give that a go.
That looks great @Box! How did you get the curve to look so smooth? Did you use the method that you posted previously with the slight arcs or did you do something else? Thanks so much again 
I started with a 96 segment circle and cut a 15 deg wedge from that to use as the single component. This gives an outer curve of 4 segments per step, enough for a curve and not so much that it is overkill. Giving you 24 steps in 360 deg. You can change the numbers to make more or less steps.
So in the image above you see the component on its own, the stack of components forming the structure in the middle, then the whole thing made into one with outershell, possible because the component is a solid, then a bit of a chop at the bottom and top leaving you with a single solid component.
Thank you for your explanation @Box. I kind of get what you are explaining, but not entirely sure I follow. I’ll try and see if I can re-create what you have explained and let you know how I go
@Box I understood the 96 sided circle with 15 degree angle. however I don’t understand how the stack of components to form the outer shell is formed ? Only if you can, (totally understand if this isn’t possible/or if you don’t have time) could you kindly create a video demonstrating your explanation? I really appreciate the time you have taken to explain this for me. Thanks very much
Does this help?
Note that I position and then extend the step down, this is purely to give it some meat when you use outershell. If left with just the edges joining the result created wouldn’t be seen as a solid. How you smooth the underside is up to you, it can be done with 2 triangles and a soft edge, or left stepped.
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SU must be doing you the favor of Autofold when you put a slope into the rail.
I didn’t have that experience in trying the method. It created nice quad like triangles at the top. Might depend on scale, number of segements, or how steep the stair is.
However I originally held back a couple of side comments.
Is Outer Shell an “extension” or “native tool” per OP’s first post. The same effect might be obtained with a little work on the component.
Pulling the ends of the railing arcs down distorts them laterally–yet for this use it’s not much at all and the modular effect brings the rail back to a vertical edge at every step anyway.
You have used a 12 segment arc, i have used 4 segments.
Outershell is available in the free versions.
You could explode them and remove any internal faces.
There is a tolerance outside which SU will make bad choices, as shown by @Anssi , you can help SU do the right thing by giving it some geometry to play with. There are plugins to do this, split sausage for one, but we are talking about doing all this extension free.
So, much like manual stitching to close a face it helps just to draw in the hidden geometry to control the slope.
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@Box you are a legend!! That makes total sense. I was missing the step for offsetting the curved detail. Thank you so much for taking the time to explain and do videos for me. I am very grateful and really appreciate it. Thank you!!
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You’re welcome.
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I’ll just throw this in here too before someone asks how to do a rounded top. This is one of the reasons many of us have been asking for weld to be a native tool, it allows many more possibilities in the web version.
Just to explain what is happen here, in wireframe mode I select all the edges, then use Shift select to deselect the verticals, which allows me to unsoften and weld the horizontals so they will move together.
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