Cull smaller (area) of two coplanar surfaces

Hi,

I am trying to compare two coplanar surfaces based on area and cull the smaller of the surfaces. The surfaces are shared walls of adjacent extruded cubes. The cubes are extruded at varied heights. I want to keep the larger wall between each cube and delete the smaller overlapping wall from the data structure. If there are two surfaces of equal area, I want to cull one of them. (In others words, I only want one wall between each cube cell.) I want to do this because I plan to render the cube extrusions (on a very large surface) as different materials and I need to eliminate overlapping surfaces. In the attached image, you can see the overlapping surfaces at the intersections of the cubes. I have done similar culling operations but I am having trouble with this one since I have to compare these specific area relationships between cubes. ANy advice would be much appreciated.

Matthew

Tags: cull, surface

Attachments:

Blocks_WRK.3dm, 664 KB
Blocks_WRK2.gh, 8 KB

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Permalink Reply by Matthew Schexnyder on November 26, 2011 at 10:00am

Hi All,

I though I would put this question back in the queue. I have attached an updated definition in which I am trying to compare the overlapping surfaces with a shared XYZ point (similar to using the centroid for sorting duplicate surfaces). But, that's my theory...I am not sure how to manage the lists to then compare overlapping surface and then cull them from the overall assembly. Any help would be appreciated. Thanks!

Matthew

Attachments:

Blocks_WRK2.gh, 14 KB

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Permalink Reply by Taylour on November 26, 2011 at 11:07am

I'm probably not advanced enough yet to be of much help, but maybe some combination of these:

Math » Operators » Larger Than

Sets » List » Dispatch

-Taylour

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Permalink Reply by Andrew Heumann on November 26, 2011 at 11:49am

You were on the right track. Here is my approach:

Get the center point of each face
Project that center point back to the base surface, and get its UV coordinates
Round off the UV coordinates to avoid slight inaccuracies
use "Create Set" to create an index map based on duplicate points
use "assign paths" (a custom cluster I wrote) to put the faces into branches based on create set's index map
within each branch, sort by area, and extract the larger one.

Attached is a definition that demonstrates. Let me know if you have any questions about what I did!

Attachments:

Blocks_WRK2_andrew.gh, 23 KB

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Permalink Reply by Matthew Schexnyder on November 26, 2011 at 7:15pm

Thanks Andrew, that works very well. It is still a bit mysterious to me since I have not worked much with sets at this level, but I see what the definition is doing in principle. I'll have to study it more! Thanks again for your reply.

Best Regards, Matthew