Curved stringers / stairs

I am trying to create curved stringers for this stair. I have made the treads components and grouped them as stairs, and made an inner and outer wall, each as components also. I would like to make these stringers so that the treads float between. I am a little familiar with some of the plug-ins out there such as Flowify, Shapebender, etc. though don’t feel experienced enough to use them. I do have Fredo, though can’t find the tool to do this if one exists. Is there a simpler way to adjust the full height walls to make them say 12" high stringers that curve from the lower floor to the upper floor. I left the old stair on a hidden layer to show you what I am trying to achieve.
Curved stairs.skp (3.5 MB)

  • draw an arc;
  • use Adebeo PushLine to push the arc (for height);
  • use Joint PushPull for offset the faces;
  • make it group.

Before doing anything, don’t forget to group or delete the old stair, now it’s just raw geometry hidden!

or you could use Eneroth Upright Extruder


Thank you Mihai, those plug-ins worked like a charm. I have uploaded what I did, curious how you would treat the top end of the inner stringer. I tried to finish it with arcs, but can’t close the faces or get a smooth curved transition as I can’t get it to be coplanar. Also can I increase the segments in the initial arc of the stringers to make the curve more uniform.
Curved stairs-2.skp (3.3 MB)

A possible solution could be this:

1 Like

Or like this, with Fredo Tools > CurviShear and Eneroth Upright Extruder

Thanks for that Mihai. How did you determine the length of the straight stringers? Is that shapebender you are using. Also are there tutorials on how to use these extensions. You make it look easy, but I have no experience with this, same as the example below using curvi-shear.

There are a lot of tutorials, you just have to search on Youtube.

The length of the straight stringers it’s and must be the same as the curved one. If the curve edge is an arc and length does not appear in the Entity Info panel, explode it and the total length of the segments that compose it will appear.

ex for CLF Shape Bender:


Okay, thanks again for the information. I will search for tutorials and play with the extensions before applying them to the model. It is amazing what this program can do.