How can I make these faces

[msmyeong]

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!!

[sovitek]

Hello…try extrude as solid

[msmyeong]

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

[sovitek]

alright… could you share you dyn ?

[msmyeong]

stairs.dyn

this is the file. thanks!

[sovitek]

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

[msmyeong]

very thanks! I’will try!

[jostein_olsen]

or you can loft beween two sets of your curves:

[sovitek]

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

[Elie.Trad]

Without packages :

[msmyeong]

thanks all of you~~