BlendSrf Simple two NetworkSrfed Surface

Tried to BlendSrf a two simple Networksrf generated surface,
but can not BlendSrf.
There’s no errors shown but the pop-up for the blendsrf comes up
just for a second but closes immediately and the command is closed.

If I cut some parts off the surface then blendsrf works ok.

Is there any limitation on using blendsrf on surface created by networksrf?

Blendsrf_networksrf.3dm (185.5 KB)

NetworkSrf regularly creates surfaces which have issues for further modelling.

You can get around it by cutting back the edge and splitting it at the first knot:

Blendsrf_networksrf_01.3dm (308.0 KB)


Hi Andy - what do you mean here, exactly? If you mean they tend to be be fairly dense and not amenable to point editing, that is one thing, but this looks like a bug to me so far - do you encounter similar on a regular basis?

@Toshiaki_Takano - cutting back the edges may have a good side-effect in this case as well if you are making a curvature continuous blend - it will not dip down as it will from the edges as you have them. If you want the overal shape to be ‘fat’ and convex, then a g2 blend cannot start at the very top as you have it:


Hi Pascal,

Yeah, I’ve encountered this a few times in various guises but I thought it was down to my poor understanding of some of the limits to some commands in Rhino?


Thank you for the feedback.
I guess thel tool is a bit unstable sometimes…
Trying to make an animal shape and was thinking
networksrf might be the way.
I guess it’s ok, but I need to use other tools
when encountering problem such as this.

Thank you for the feedback and advise.
Is there some things that can be avoided to not encouter this bug?
Is it networksrf problem or blendsrf?

Well, what are you trying to make? If I was trying to make a shape like that I would not use NetworkSrf, and would likely make it all as a single surface using different methods depending on the final goal.

I’m thinking of modelling a cat or other organic shapes.
Was thinking networksrf might be a good start for the head and limbs.

I would say BlendSrf is having a hard time with the singularities at the corners - but that is just a guess and cannot be the whole story anyway - it works on the lower edges and it works if the surface is split back on an isocurve,


Ok. I’ll just play around some more.
Thank you for the support.

For those sorts of shapes it’s probably easier to sculpt them with freeform point-editing from basic shapes, see the “rubber duck” tutorial in the Level 1 manual for an introduction.

Thanks @JimCarruthers I’ll take a look any try out couple of solutions.