Porosity: Punchouts from High to Low Density

Hello,

I am a newbie and have a basic question I'm hoping someone can point me in the right direction. I've searched online though videos but still not finding much to help (I also don't exactly know what to search for..).

The Question: I have a basic tower and I want to punch out voids with two different sizes of ellipses, I don't want to skew the size of the ellipses. I do, however, want them to be denser at the top of the tower then gradually have less and less of them as it goes down until there are none.

As I'm a newbie, I've set up the ellipses and a basic tower but don't know where to go from there.

Thanks for any help,

Cliff

Attachments:

Porosity1.gh, 10 KB

Replies to This Discussion

Permalink Reply by David Rutten on October 5, 2017 at 2:18pm

So the tower is the cylinder, and you want to just cut holes in the surface? Or do you want to cut holes through the volume? What's the orientation of the ellipses, long axis horizontal? Random?

Do you want to cut holes by extruding the ellipses through the skin, or do they need to be wrapped onto the skin? Important, as it will result in differently shaped holes.

How close are adjacent ellipses allowed to be? Are they perhaps even allowed to intersect?

What sort of control do you want over the distribution? Do you want to specify a lower limit below which no ellipses will appear? Do you have an exact equation that describes the density?

Do you have a fixed number of ellipses you want to distribute unequally, or is the amount a result of the density function + random chance?

Permalink Reply by David Rutten on October 5, 2017 at 2:30pm

Here's an approach for generating a fairly random point cloud with a high degree of control over falloff. I start out by populating the tower with loads of points, then removing some of them. The removal is controlled by distance to an attractor point mapped to a graph curve. By comparing this mapped distance to a random number some points will be removed, others will survive. The percentage of those removed will be higher where the graph is lower, i.e. near the attractor.

You could of course also start with a regular grid and remove points from that.

Attachments:

Porosity1.gh, 21 KB

Permalink Reply by David Rutten on October 5, 2017 at 2:48pm

And a more advanced version which also removes points too close together and populates the remaining points with aligned ellipses.

Attachments:

Porosity2.gh, 25 KB

Permalink Reply by Clifford Bourque on October 5, 2017 at 8:15pm

David, thanks for your help!

It looks beautiful, and is very satisfying sliding that number slider and messing with the graph.

I'm looking to cut the ellipses (long axis horizontally) into the surface, then I'm hoping to do Delaunay triangulation (or something better?) and make a triangulated structural skin out of it...(its gonna be a flying drone tower, the holes are how they get in and out)

But currently I don't know how to cut the holes out, I'm unsure how to extrude the curves straight out...(don't know how to specify the axis)

I think the current configuration with the graph and the attractor works very well, if they didn't hang off the top edge that would be better, but I can just delete those in Rhino.

Again, thanks!

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