Advice on modelling a continious surface cocoon

Hi Everyone,

I’m relatively new to Rhino and I’m looking for some advice on moddeling the following shape as intuitively as possible: I want to model a sort of cocoon which consists out of one continious surface that folds in different directions to form the walls, floors and ceilings of the pod. See the image (however the 2d section doesnt show its complexity consisting out of one continious surface). So far I’ve tried to model it by using Subd but hopefully somebody has some advice for me!

Cheers and thanks in advance!

I’d recommend you spend a little time going through general modeling tutorials so you learn about NURBS surface structure and how it relates to shapes.

Then you’ll be able to ask more specific questions people can help with.


Hi @a.h.brouwer,

Welcome to the forum. If you are going to model this in Rhino (and I’m not at all sure Rhino is the best tool for the job) then SubD is certainly the way to go.

I wouldn’t try to model the complete cocoon as a single object. I’d treat each inner space as a “room” and model it as a closed SubD object, then place the rooms adjacent to one another, remove faces where they open out together and use bridge to join them. This approach will eventually lead to a complete inner surface of the cocoon.

Then remove faces where you have openings to the outside and extrude the edges outwards and start to build an outer surface from there (or alternatively build a complete outer surface in the same way as the rooms and delete opening faces and bridge inner and outer).

This seems to me a very ambitious project for someone new to Rhino and SubD. I’d go look at the YouTube videos on Rhino SubD modelling by @theoutside. One of the big lessons there is that he spends most of his time remodelling and adjusting to get things right. Be prepared to get frustrated, but persevere and you will get there!

Good luck


from what i understand is that this might be a 2nd semester student who had his midterms and is seeking for a fast way to complete this job. time it really not plentiful available in such situations… the pressure is high. as a first or 2nd semester they´d be happy to scratch it up anyhow.

he probably meant that the actual model should consist out of a continuos surface, he sure wont mind patching it together under the hood.

@a.h.brouwer your project reminds me very much of the endless house from Kiesler, just in your case a rather vertical version of it. if you dont know it i recommend to check it out, it might give you some ideas how to proceed.

in fact i modeled something similar once and used actually subd for the result. deleting faces allows you easily to create organic openings. a different approach would be that you start from a deformable sphere which you stretch into position or a simple closed loft. from there you start triming holes for the openings and place surfaces or rings depending on your intent inside which you then blend together with BlendSrf for instance.

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Thanks for this great reply! Modelling the rooms as a negative and extruding outwards for the outer shell seems like a good idea. Quite intuitive as well and already got some succesful tests.

Thanks for your reply!
It is my thesis project actually - And indeed I have to finish the project in 2 months so ‘technical’ perfection is not of essence (However I am always a bit of a perfectionist when it comes to modelling haha). I have worked in Archicad for 6 years but I never did a more freeform / fluid project where archicad is quite limited in, Hence I’m switching to Rhino now to model this project. Didn’t know the Endless House, that’s a really nice reference, thanks. Especially on the subject on physical models. Didn’t try the loft method yet but it also sounds like it can work - Will give it a go!

I’d look at it as an inside/outside wall thickness part. Imagine two revolved shapes, one represents the inside and one the out, they can be connected or not. as needed.

The inside shape can extrude, bridge and connect as needed. You can then revolve sections of it and bridge them together to create the stalactite/stalagmite bits.

The outside would simply be a copy/ offset of the inside, that you’d then extrude the spiked sections out in the normal direction.

This looks complex, but if you break it down into it’s elements it is a pretty straightforward subd exercise. The benefit is you have a lot of freedom to interpret the shapes, so you can kind of “find the way along the way” and design this in 3d with the sketch as the most suggestive of guides.

something like this comes to mind…