Beginner looking for advices on smoothing edges

Hi everyone,

As the title says, I am looking for advices on a modelisation that is giving me a bit of a headache.

I was asked to model a element of wall cushioning following these instructions. Lengh is in centimeters, the cushion has to be 6 cm thick.

After a few trials and errors, I settled on revolving a curve from the center of the pentagon with its periphery as a rail.

Which gave me this shape. I am quite satisfied with it, but as you can see it has 5 pronounced edges while the designer wants a smooth surface.

I have tried unsuccessfully a lot of different options to get rid of those edges. The variable fillet/blend that was my best bet didn’t give me the expected result, and trying to erase these edges or smoothen the creases on subD surfaces with Rhino 7 WIP didn’t work either (I have no screenshots for this since I can’t use WIP version with the temporary licence on my home PC)

The best result I obtained was by trimming the surface then use the blend between surfaces tool on tangency.

However, I am not quite satisfied wih the result. While the main goal of smoothing the edges has been reached, the connections between surfaces are not clean and quite visible under the light, the blends are a bit bulbous in some places and since and I can’t fuse my surfaces as a single object with boolean union since there are probably some continuity errors along the borders.

I have not touched Rhino since I was a student and thus don’t really know how to fine tune the functions’ parameters, thus I decided to come and ask here.

What functions should I use to get rid of these edges and how should I configure them ?
And eventually, If I can’t do this with Rhino, what other software could I use to realise this ?

Many thanks in advance.

PS : If anyone could also tell me how to get rid of that god damned anime profile picture I have since highschool that the forum used on it’s own even after disabling the Gravatar account linked to my mail, that would be really appreciated.

Try extracting several isocurves in the U and V direction, then use those curves to make a NetworkSrf

Hello - I would make a nice simple convex pillow surface and then build up to that with transitions from the hard edges. For this, I think I’d make a control point curve approximation of the polyline and make copies of that as in the attached file, the inner ones smoothed out. Surface the curves using Loft with the Loose style. The surface can be adjusted (relatively few control points) and then MatchSrf-ed to the top surface.

AnglyPillow.3dm (231.9 KB)


Thank you both, a lot.
I’ll try this in the weekend and maybe come back for clarifications if I’m really stuck, but I think I should manage to do it on my own now.

Good evening,
So, after a few hours of trials I realize that I am indeed completely stuck.

As you suggested, from my base polyline with 5 control points I generated a few more where I softened the corners with Fillet curves, and another with the Control point curve tool to use as the topmost curve.

I then used the Loft tool with the Loose setting on my curves, and ended up with a result far from what you showed in your exemple.

I tried different things to reach a better result : using more curves for the loft (up to 5), changing the shape of the inner curves, raising the curves degree thinking that more control point would give the tool more room to work, or moving the surface control points along its edge to arrange them in a better way, and none of those methods gave me a better result.

Since you were able to show me a demonstration, it means the method works and my problem comes from me not understanding something, not setting the parameters in the correct fashion or making a mistake when building the curves, but for now I can’t determine what I am doing wrong even after spending a good part of my afternoon on it.

Would you perhaps have a few pointers or additional suggestions for me ?

Again, thanks in advance.

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I would try putting a tiny radius on each of the 5 corner intersections, then creating the 3D from that path. Not sure in Rhino but I’ve had similar successes in other programs.

we must know.
to have a clean loft surface you need two conditions

  1. the section curves must have the same degree and the same number of control points.
  2. in the case of a periodic curve, make sure that the join of the surface starts at the exact same place of the curvends for all section curves
    (.another condition.
    the curves must be uniform too).

combining these conditions results in producing a clean surface.

according to my analysis of the file shared by pascal
I see that he has recreated the basic curves
in a clean way

to change your profile picture
see this discussion

Hello - take a look at the curves in my file - red, I think - note they are all exactly the same curves, except that some have been point-edited.


Alright !

Thanks to everyone, I manage to do what I wanted !

As pointed by Fares, my problem came from me trying to Loft with a base curve not matching the others, both in degree and control points number.
So I rebuilt my base line and then, as shown by Pascal, offset it while widening the angles to build my array of curves.

After MatchSrf-ing with my top surface, at the suggestion of the designer I added a small elevation on the bottom via a 2 rail surface using the base curve with sharp angles, this way the cussions can be arranged without a space between them as he wanted.

Thank you Pascal for advising me on the method, Fares for indicating how to properly apply it, and everyone else for your suggestions.
Having very little experience on the soft, it felt very rassuring to know I could adress the community if I was ever lost.