How do I Cap blobs or other organic shapes?

Hi, I’ve been trying to create a closed “organic” shape in Grasshopper as exercise but I’ve been having problems with the “closing” part. I can to it in Rhino, but my method is splitting the surface then blend the surface to get it to close but it takes a little too long and also I’m not very good with that command since I always get weird shapes. I think my mistake is that I’m not having the surface edge on the proper direction because of the splitting. Anyway.

Here’s a picture of what I want any my Rhino and GH file. To explain, my intention is to create a tool that could let me make shapes with lines drawn and create from blobs to graph based geometries. Thanks, I hope I explained myself. (12.4 KB) Huno_random_wormtyep.3dm (98.7 KB)

Thank for the fast reply. But I am looking up to having the caps follow the curvature maybe or have similar effect as Blend Srf command in Rhino!,

Thank you Rajeev!

Sorry if I reply my own thread but I would like to give it bump and try if someone has an idea!


Try the ‘rail revolve’ component using the end curves of the ‘worm’ and generating a profile curve to sweep from the centre point of the end curves. See below;

Yes, I tried that one as you can see for the point in curve and also the curve on Rhino but I can’t seem to implement it in rhino. The thing is that I just wanna make blobs.


It’s difficult to match the curvature if your shape is like this in general. But a simple solution is to create extra circles at the ends decreasing down to a diameter of your documents tolerance.

Yea, I guess the best way is just use a Mesh and SubD and model around that framework. Because for example using an arch will end in a spherical end, and well the way I did it was to dup the edge and work aroudn that just add a line at the center and push 3 point arch, and I did the revolving but I have to define a shape.

So, I guess there’s no solution.
Maybe just use weaverbird.

Staying to Surfaces has advantages

But this is not going to work, you don’t have a match surface command in GH, nor surfaces created like this, are suited to ideally match. Even if you would have a match surface component.

Have you even tried what I was saying, maybe I wasn’t clear?! I’m just saying add additional sections and let them decrease to a very tiny size.

You could use meatball techniques to create blobs. Then with rhino 7 a quick Quadremesher > subd > NURBS, depending on the final geometry type nessesary.

Hey, @TomTom !

Yes, I did what you proposed, that also made me try something like a specific height so that the circles can go to a parametric limit. And I wasn’t thinking about match curvatures so thanks for clarifying that.
Sorry if I insulted you thinking that I ignored your advice.

What I meant to say with my reply is that maybe it is better to just model the thing as a closed geometry, mesh or surface.
Since this worm came out of a surface, I was thinking of modeling it as a folded piece of paper and then just close the ends and that’s it, I can 3d Print that and mount it. I also thought of trying again the @Patt solution but with an extended seam curve from the worm and then split it with the edge, flat cap it, find the center to push an axis normaled to the capped surface to the and revolve that profile. But I will post those solutions maybe tomorrow.

Thanks, again! :grinning:

oh, yea you are right. I forgot about metaball stuff. But now I feel like metaball is pretty much gets you the same results? I don’t know I feel like it’s the same geometry sometimes. For example I see the Kuntzhaus Graz and I did a similar shape with a surface and symmetry it in rhino, but when I wanna cap it to make it a bean, I don’t know how, but I will try soon some of the stuff taht just came to my head, thanks @scottd !

Kunsthaus-Graz was one of the early Rhino projects:

One of the key turning points in learning what could be done.

I think at that time most of the overall shape was direct control point manipulation of a periodic surface.

If we were to do it today we would use Rhino 7 SubD objects as the foundational form.

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You could use your radii for pipe variable with a round cap:

or, ‘steal’ the cap from the pipe variable, ‘glue’ it to the loft via map-to-surface + rail-revolve combo:

achieve the same (without pipe variable) via spheres at ends of your lofted shape:

Though results might be slightly discrepant at transitions from loft extremity to cap, you can smooth the object once meshed afterwards or fine-tuning it with the graph maps beforehand.

Similarly, you could construct your rail revolution with the same spheres at the ends:

Just some ‘tips’ (lol) - maybe they help - SubD would definitely add a different level of play :slight_smile:


Just remembered showing this quick (manual) example to someone in the past - you could establish a similar method via isocurves from your ‘blob’ shape in grasshopper.


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Oh, my! Thanks! Let met see your screens and see if I can get it! Thank you very much , I will come back with results Once I get it, of course.

oh yess! Something like this came to my mind! I will try it out.
Practice, practice.

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! Thought I attached the file!
Here, if you want to take a ‘closer’ look: (56.1 KB)


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wow, it is a complex patch! Thanks, I’m reading it r n !