Hi to everyone,
I’m trying to create a nice smooth surface according to the set of curves you can see in the picture, unfortunately I didn’t get a nice result. can you give me some tricks? I tried with NetworkSRF and also combined with sweep2.

thankssrf88.3dm (239.2 KB)


Do you have the result?
I think you have everything in this lines.

(Pascal Golay) #3

Hi Andrea -this is a pretty tricky shape, I’d say. The curves are adequate, in a way, to define this shape for a human observer, so to speak, but are not all curves that are very useful for actual input to create the shape from surfaces. I generally find it best to try to isolate the simple shapes that define the overall character of the thing and separate that, where possible from details, or transition surfaces such as fillets and blends that might be needed between the main surfaces. But. The distinction between the two is not super easy to distinguish in this case.

Is there an image of this thing? Does it exist or are you starting from scratch?



This is a really hard one to do. Focus on making clean bezier surfaces. Having a smooth form is more important than adherence to the curves. This is the surface patch lay out I would use (do not use the patch or network surf commands).


I have have open the file and try to do it. It’s has a few nice challenges in some surfaces.
To do this type of objects i always try to:

  • have the same number of points in the curves that i use sweep 1 and 2
  • in sweep try all the diferente possibilities like refin with, rebuild…
  • use a lot of splitatisocurve and adjustable curve blend

Usually i also do the objets with straight lines and only at the end do the fillet’s.

I hope to be helpful.


Not a great result at first, but playing with BlendSrf inputs and some surface matching (MatchSrf) may be a positive direction. Below image was created in a bit of a rush, but note that the curves with simplified first (joined, rebuildnonuniform, split along centreline).


Thanks for your reply and effort. It looks really close to what I’m looking for, but I’m curious to see how it look the reflection , especially in the area marked with the red spot. can you please post the file with the polysrf?


Hi Ncik and thanks for the fast reply , it seems twisting isn’t it? Did you check the reflection?


Hi Pascal, you can see the object here. I hope is enough.


You can also get a result like that if you ‘sculpt’ your surface by extruding a clean base profile, adding control points to the result (with the InsertKnot command) and manipulating the surface points directly.

If NetworkSrf etc doesn’t work and you don’t have time to revisit your curves this is my best guess.
Hope it helps.


Thanks, time is not a problem, what you see in the link is already modeled in rhino but I’m not satisfied about the surfaces, I would like to understand the best way to approach to this kind of shape.


Sculpting is like doing control point editing for clean surfaces and gets the equivalent result - at least for me - to Box Modeling of other designer software in Rhino geometry terms. You can get precise clean results in this way too.

All this only if you understand how rhino curves, surfaces etc work in theory and Loft, Sweep, NetworkSrf etc isn’t enough for you. Sculpting is covered in Rhino Level 2 pdf – and even better if you go to the online class.

In the file you uploaded some of the profile curves aren’t clean (many control points, product of offsets and copies) and also don’t define your intended result fully. This shape can be done both from a network of clean curves and sculpting.

srf88-fin.3dm (332.6 KB)


Hi fin,
I’m completely agree with you, the center curve is not clean enough, but I cannot understand why the base profile isn’t clean.
however The curves I made are the measurements result of the real object. As I said before I’m not designing but I’m investigating the way to improve the surfaces quality.
Probably I need to understand exactly what clean curves means.



It’s simple trimmed helper surface.

(Pascal Golay) #15

Hi Andrea - judging from that image, I’d guess the shape is quite a bit less ‘swoopy’ than you have set out with your curves. It looks rather more manageable, to me, in that it looks like there is a clear distinction between the sides and bottom, with some sort of fillet between. The Front-Bottom also seems like a simpler transition.

this looks like it could be a fillet-like surface and the front relatively flat:

this looks like it can also be a fillet like transition and the side surface relatively flat:

this can also be a fillet-like surface, I think:

But the main shape surfaces are relatively simple, is how I am reading this.


(Rob McPherson) #16

I love your posts! Could I come and watch you work for the day? =D


Here’s a solid modeler approach. There’s just one tricky bit to trim out and surface in.

@mcvltd Thanks for the compliment. I’m doing mostly laser cut panels these days. Boring work that pays the bills. Need these challenges to keep my skills up.


Yes it is twisted and awful, but I think there is scope to improve it based on the basic workflow of using BlendSrf.


thanks to everybody for the suggestions, very helpful. Unfortunately is a busy Friday but I will send new results, hopefully the beginning of next week.


Hi, do you still have the file? can you post it? I’m curious to analyze your surfaces. ciao