# Sand form-finding

hi guys,
I am writing here to ask if you might give me suggestions about how to achieve this “sand form-finding” (don’t know if the keywords are correct) in grasshopper for a roof compressive structure.
I am average gh user, not expert
What i would do is use a voronoi pattern generated according to some defined points. Then I would use those polygons in kangaroo and use their vertices as anchor points. Too naive?
thanks

1 Like

It is strange you didn’t find on this forum !
Search medial axis sand dune …
You must find what you need

I think this is a different process and result, am I wrong? sand dunes are modelled by wind, while this is by gravity.

Did you open the links ?
Yes we speak of gravity no wind

I´m prety sure the image you posted works with gravity. The holes are the inverted cone vertices that intersect with the voronoi edges to form paraboles. It works fairly well with voronoi as the center of each voronoi polygon is actually also the center of a circle…

You can actually use the surfaces to generate the Voronoi, rather than the other way round.
Just boolean together some cones and you get this shape.

1 Like

So there is no catenary involved?
assume I would have to close the holes (if I have to make a roof), wouldn’t that be a small catenary that fillets the cone surface? and, the bigger is the hole, the more visible would be catenary shell over my head, right?

Is something like that good ? Can you bee more clear of what you want ? Draw a sketch. What are the inputs ? How you plan to use output ? Real thing, structural optimization … or just some school question ???

Yes! that is what i am looking for!
the aim is to make a roof out of it!
thank you

Ok, here it is a mesh, if you follow Daniel Piker instruction you can use also Brep.

Draw in Rhino a contour shape, then place circles then select all the curves and make a planar surface, use command planaSrf.
Then choose only inside curves to feed in curve component
Chose your hollow (trimmed) surface to feed in Brep component
Beware of the size of “Max Edge”
sand dune using mesh homes.gh (23.2 KB)