Handrail problem

Hi all
I have searched the forum a bit but since I already have a hard time trying to synthetize my question I couldn’t find any answer.
Hope I won’t bother anyone with this.

Anyway, to make it as simple as I can, I’m trying to model a handrail for a strange shaped starway (not a simple rectangle/cylinder thing) with a complex detail (not a simple circle/rectangle section). (ill.1)

The sweep command is great, but it rotates the section according to the shape geometry, and I would like the section shape to remain as it should (ill. 2), meaning with the curved part on top of the handrail, and the flat part at the bottom (ill.3 showing the problem).

Anyone know a way to do this either with grasshopper or simply with the basic rhino commands?
Here is the rhino file, and the GH file which is mostly me not knowing how to do this.

Thanks a lot in advance

Best regards
unnamed.gh (5.6 KB)
POUR MC.3dm (510.3 KB)


Sorry I can’t open you 3dm because I am running the wrong version of rhino, but maybe try play around with your sweep styles, try "Roadlike top”.

Hi Ddaniel187
Thanks for your reply, unfortunately, for some reason this option is not available. I have tried setting a serie of cpplane in GH along the curve, but I didn’t manage tto do naything more than perpendicular cplanes at specific points and even so, from then I don’t know what to do…


I think the problem is the direction of handrail of yours can`t match the curve Pframe directions.
You can evaluate the curve with 10 Pframes(the more evaluated Pframe pts, the smoother shape you get), and then align these Pframes to the directions you want. Finally you get 10 geometries with right directions and go Loft.

Hi Lei
Thanks for your reply.
I already have tried that, but the path shape is rather complex and the number of planes to set is long… I was looking for someone to point me to a turnaround with GH to automatize this…

can you convert your 3dm file into V5.0?

POUR MC-R5.3dm (505.0 KB)
There you go

Does the design suppose to make the profile(your complex geometry) bottom flat crv facing vertically downwards?

POUR MC-R5.3dm (88.2 KB)

unnamed.gh (8.4 KB)

check if this is what you want. :slight_smile:

Will do Lei Yang, thank you very much.

Dear Lei Yang
I think it is close enough for me to play around with it before I bother eeryone again, so thanks a lot.

Best regards