Sweep2 rails: edge continuity and/ or Blendsrf component

I am looking for an option to create a 2 rail sweep in Grasshopper with an option to set curvature continuity to G2 for the rails. Is such a component available in a plugin or with custom code?
The same goes for a Blendsrf component with inputs for G!/G2 like you can find in Rhino, is that available somewhere too?
Thanks in advance!

G1 meaning tangency and G2 curvature?
There is an api method that can be called.

I’ve put it in this for you.blendsrf.gh (51.2 KB)

no idea about sweep2 tho


That’s great!
For the last 45 minutes I’ve been trying to rename the inputs, because I use full names and that makes it easier to remember if I save the component for reuse. I couldn’t get it to work with my names despite replacing them in the script itself… :confused: Would you be so kind as to rename the inputs like this:

blendsrf.gh (49.0 KB)

try this


Awsome, I am going to use this thing like crazy! :smile:

@Will_Wang if possible can you please have a look at this.
I try to use blendsrf on this example but with didnt work as expected :frowning:
Any ideas how that can be solved usingyour script?

Thanks in advance

blendsrf_gsy.gh (10.4 KB)

it seems to me that the RhinoCommon call can’t handle singularities at the two ends where the edges meet. Not sure who would know better. Maybe @dale

Hi @g.synetos,

If you bake your geometry to Rhino and then run the BlendSrf command, do you get the results you expect?

– Dale

@Dale yes it works as expected.

@Dale do you have any idea why that happens, and do you have any alternative solution how to achieve the desired result?

Hi @g.synetos,

I am able repeat the problem, and I’ve opened an issue.


The only alternative I can provide at this time is to use this version of Brep.CreateFromSweep. Include the points where the edge curves intersect. You’ll need to cook up at least one shape curve. You should be able to use Brep.CreateBlendShape to do this.

– Dale

Thanks @dale

Is there any example on how i can use these functions?
While i m fluent with python, i m not familiar at all with VB or C#.
I suppose it should be something straight forward to just call such a function but i m not familiar with the syntax :frowning:


Brep.CreateBlendSurface Method failed.gh (19.8 KB)

I am trying to blend two surfaces using @Will_Wang 's script today but still had an angled edge.
I am not sure if this is because the script hasn’t gotten an update or if the bug still remains.
The first picture below is a comparison between BlendSrf in Rhino and The script.

Hi @Quan_Li,

The Brep.CreateBlendSurface and the BlendSrf command are only similar in name only - the former does not use the same code as the latter, which is unfortunate. The goal is to have the two work the same. But this won’t happen until sometime during the Rhino 8 release.


– Dale

1 Like

Got it, Thank you!