Hi to All,
Can someone help me about how to model a Helical staircase and Balustrade in Sketchup?
Which kind of extensions do I need?
What is the best-simplest way?
Thank you,
D
You can do it with the native tools.
Plugins could make it easierâŚ
Helical Stairs [often incorrectly, but very commonly, known as âSpiral Stairsâ] have to follow a set of interacting rules - varying by building-type, country and area - but many rules are common.
You need to check your local building-codes - no plugin is going to do everything for you.
So letâs assume that you establish that for your building/area the minimum width is 1000mm, the maximum taper of a tread is 15°, and the rules say the âgoingâ mid-tread is 250mm and the minimum going at the center is 50mm, and the treads should overlap by 25mm, and other rules say the âriseâ needs to be perhaps 170mm [this depends on the going and the total rise etc]âŚ
You now have everything needed to make a component tread.
Draw out the constraints using the modelâs origin as the componentâs center.
Add 3d thickness to the tread etc.
Lift the treadâs geometry up by the âriseâ.
Exit the edit-modeâŚ
Use the Rotate tool on the component-instance, press Ctrl to instigate âcopyâ and rotate the copy 15°.
Move the copy up by the âriseâ.
Check that the treads relate to each other as you expect.
Now you can use Rotate+Ctrl to copy the two selected treads by 30°.
Move them up by 2xrise.
Now repeat with the four, and Move up 2xrise etcâŚ
Repeat until you have the required number of treads in 3dâŚ
Now you have a set of radially array treads, each stepping up by the âriseâ.
You can edit a tread and add some baluster posts and a sloping piece of handrail around a 3d-arc - look at followme etc.
If you hide the end edges of the rail theyâll fit together nicely with their siblingsâŚ
The first and last treads will probably each need âmake-uniqueâ and then editing to form different handrail forms bottom/top etcâŚ
Stairs are one of the most complex things to design and get right - âspiralâ ones are perhaps evn worse !
You can try â1001 bit toolâ too. Take a look no YouTube 
My StairMaker plugin will do curved stairs, spirals etc.
Hi TIG,
Thank you⌠but actually my focus was more on how to have an helical solid balustrade (e.g.)âŚ
I guess it is a sort of loft function (?) just weird is not normally included in a modelling program?
Hi Eduardo,
1001 bit tool looks great⌠but sadly it seems there are no versions for SKup 2017 
only up to 2015 version (?!)
Hi gkernan,
where is you extension, do you have a link? Is it freeware?
His excellent GKWare Stair Maker v1.0.32 is available from Sketchucation.
Hi Dave R
Cost?
and also⌠how does it make the staircases? is it parametric? and after if I want to edit and personalize it?
e.g. if it is not perfectly helicas but more bespoke?
Making a âhelical pathâ [or a similar complex path] is relatively straightforward.
There are several tools to do it, or you can make it manually.
You can âweldâ the parts into a smooth curve as desired - there are several tools for this.
You will then need to extrude the handrail profile along it.
The native FollowMe tool is fine for a circular profile - just make sure the seed-face is perpendicular to the start of the path, select the path the activate the tool and select the face - you might need to reverse faces if it is made âinside outâ.
If you have another profile - e.g. a rectangle, then FollowMe will unexpectedly skew it as it rises up the path.
@eneroth3 made Extension | SketchUp Extension Warehouse to ensure itâs kept oriented consistentlyâŚ
Looking at the link, I canât help but chuckle at the idea of your plugin doing Tungsten Inert Gas arc welding in SketchUp. I canât be the first one to make that association. 
Thatâs âMr. Tungsten Inert Gasâ to you pal. 
His manors argon.
Thank you TIG!!
I will have to try⌠
Thank you ALL guysâŚ
I will have to definitely tryâŚ