Hey folks,

The challenge is to make the fastest polygon island selection compound possible. Your compound has to work out of the box, as we don't want to install plugins, addons, workgroups or anything else (so I think you will need to rely on factory nodes).

I have attached my own polygon island compound along with a test object for you to compare performance. Please make something much faster, or pimp my existing compound
Depending on the island, my compound outputs the same polygon indices multiple times. I don't mind because it's not typically a problem for ICE Topo. If you prefer to output only unique indices, feel free to go for it. But it'll likely slow down your compound.



P.S.: Just in case you were wondering, the idea for this was proposed to me by someone on Vimeo after I asked for a fast polygon island compound in my latest video.

Is it necessary to input a polygon index to select the island? If not, you can just wrap Bradley's script into a compound via PPGLogic, so on compound creation it's creates a clusters and on change of index value it's filter them

Yes.

After trying out some more things, I've managed to speed up the compound considerably. On the test geometry it's about 5 to 6 times faster than the one I posted previously. I will not post my updated compound yet - it is supposed to be a challenge after all
Just a hint: I got rid of one of the loops.

Here is CG Find Polygon Island result ( 2 m 3 s ):
http://xmages.net/storage/10/1/0/1/3/upload/d95e5f85.jpg

And here is my ( 1 s ):
http://xmages.net/storage/10/1/0/6/2/upload/1ad9f224.jpg
It takes one int as polygon index and outputs rest of faces from the shared island ( no duplicates )


I have complicated your geo example a little bit because it has been calculated both on my and your compounds mostly at real-time, and have attached my own compound, check it out please, I am not sure that it works as expected but seems like it does that

Hi,

I have checked your compound, but it doesn't give me proper island selections. It seems to always select several islands.
I have attached a new test object and my updated compound. If you could fix yours, that would be awesome. It seems very fast!

Hi Chris,
On which scene you have checked it ? On the "testscene2" ?
I have tested it there and really encounter some strange behavior, but it has been solved by adding "build from set compound"
http://clip2net.com/s/1AzEo
Could you please share a scene with this problem ?

I tried with many different objects (also made new scenes just to be sure), but it didn't seem to work with any.

For example, when I use your compound with the first test object I posted and set your compound to index 1, it extrudes two polygon islands. If I use a Build Array from Set, it extrudes all polygon islands.

I made a new scene. Made a standard 8x8 grid. Deleted the 2 middle rows and columns. Then used your compound set to index 25:

Its a quite strange result
I have got next : http://clip2net.com/s/1AC56
I have also attached my scene,2012 sp1\ x64