Create streamlined object

I`m trying to create a streamlined object, like the one in the picture but i have no idea how.

I tried it with Kangaroo and started with a sphere but the result is not what I was hoping for.

Does anyone of you have an idea?

That looks like a shape that could be modelled by simply revolving a curve (Surface>Revolve).

Since you mention Kangaroo though - are you asking about a way to take some arbitrary geometry and make it more streamlined by applying forces? - just blowing wind onto a shape wouldn’t be enough. Maybe there’s a way but I’d have to think about it some more.

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I don’t believe that without a turbulance model you can get a streamlined object, whos shape is force controled. (13.8 KB)

Maybe if you combine Kangaroo with OpenFoam… I donno…

I think you could do something assuming laminar flow, and therefore avoid simulating turbulence.

The wind goal applies pressure to mesh faces based on the projection of a wind vector onto the face normal, so faces which are directly facing the wind get a greater pressure applied.
However, I imagine there might be a way to instead affect faces perpendicular to the wind more to get a sort of erosion effect…

May I ask why would you create the form dynamically?
There is a world reknown list of streamlined forms with their dimensions. Tested and validated (NACA).[grp]=naca4d&m[sort]=1


Pressure coefficients?

i assume its a building, and these are usually not represented in the naca tables :D. but then again just assuming.

Yes, you are assuming right. Its going to be a building and not just one but two. The second one will be above and slightly behind the first one.

Its a project in the artic and the goal is to direct the wind past as smoothly as possible.

I think that is what I`m looking for.
I want a shape to adapt based on some given parameters, such as area and height. Its possible to do that with Ladybug and Sunlight but I don’t know how to do it with the wind

If the wind can be in any direction and the building(s) cannot rotate surely you will end up with 2 spheres or possibly 2 squashed spheres?

Or is there a prevailing wind?

well usually you have local predominant winds, i dont have an english equivalent word but in austria we say “wetterseite” also the specific surrounding buildings my contribute in channeling some of it and change situations slightly. so no a sphere does not have to be but something pretty egglike i assume anything else will be a compromise of shape and function of course.

No way to do that kind of shape optimization without CFD… That is if you want the best possible shape.
If you can settle for something simpler, do a bunch of variation models and study them with the same simulation setup. Chose the best result.

Alternavelly get OpenFoam, run it with Grashopper and loose months in figuring out how to do proper shape optimization there. Not a trivial problem at all.

Something like this…

For a sailing forum discussion three years ago, I applied suggestions by Tom Speer to modify basic NACA foil shapes for keel bulb design, in this simple GH model: (21.8 KB)

The ideas expressed in this model were used to produce this proposed keel bulb.

More images…


Nice Joe! Your GH skills are greatly underappreciated. Nice bulb.

I think it should be possible with kangaroo. I am a bit critical about it being constantly called a physics engine, but you could be surprised what you can achieve with trial and error applied millions of times and ignoring the errors.

Given also the fact that these buldings will be huge compared to the difference in resulting (non-converging) forms close to the optimal one.

I do believe however that using any kind of form-finding is a waste of time. Just pick the proper NACA form and orient it to best allign with the wind patterns in the area.

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Prevailing = Wetterseite I think… Prevailing wind is the most common wind direction.

Does it translate literally as “Wetter side” meaning the side that is going to get the wettest due to rain being blown at it most? If so, that’s way better than the English and I am going to adopt this until it gets entered into the Oxford English Dictionary.

hehe yes that is a nice interpretation and etymologically probably not that far from the truth. “wetter” means weather in english so literally translated weather side, so indeed the wetter side.

In the US (at least) many of the terms used by both ship designers and aircraft designers are the same - primarily because early aircraft designers used many of the same procedures as ship designers. A “wetted surface” has comparable meaning for both; for ships it is any surface that is (or can be) below the waterline, and for aircraft it is any surface that comes in contact with high speed air. These include all of the aircraft’s outside surfaces, as well as those inside engine nacelles, engine air intakes, canopy and window shapes, etc.

Vertical dimension on aircraft are called waterlines and horizontal (left/right) dimensions are called butt lines, which is short for buttock lines, and I have no idea how that one got named.


I think that’s the shortest path to success :slight_smile:

Jacqueline, what do you mean by “as smootly as possible”? Lowest drag force? Or minimizing snow drifts against the building from blowing snow?