How can I make these faces

First I’m sorry. I’m not good at English,
I’m trying to make spiral stairs, and make these lines.
I want to make these empty faces to solid. (likes red pen)
Then how can I make it! help!!


Hello…try extrude as solid

I tried, but it couldn’t 'Cannot create a solid from an open curve.;

alright… could you share you dyn ?

this is the file. thanks!

Hi @msmyeong …try something here…i use achilab for group curves…good luck

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very thanks! I’will try!

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or you can loft beween two sets of your curves:


Yes Jostein ;)…many ways here, but my experience is extrude curves is faster then surface thickness…but thats probably me :wink: hehe

Without packages :slight_smile: :


thanks all of you~~