Forums Technical Discussion Extend primitives to Primitive Island (polygon object)

Extend primitives to Primitive Island (polygon object)

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jjayakumar
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Hi folks

I'm having a group sop which has a bunch of primitives selected using a bounding box. I convert this primitive group to a point group. I have another group sop which takes this point group and extends it to a polygon island (i.e., all connected points) and converts it back to primitive group. It works fine but it is really slow. Is there any alternate method where I can do this extension faster (either through nodes or through python ) ? Any help is highly appreciated.

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-J
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asnowcappedromance
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can you post your file ?
http://vimeo.com/user2522760 [vimeo.com]
http://stormbornvfx.com/ [stormbornvfx.com]
Manuel Tausch
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jjayakumar
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Hey Manu

This is an example of what I'm doing but it is slow. So I'm trying to find a way by which this can be done faster.

Thanks
J

Attachments:
extendedGroup.hip (93.7 KB)

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asnowcappedromance
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after looking at your file I'm wondering what the reasoning of that setup is, what are you trying to achieve in the end?
Yes, you can do this in Python, but it's going to be really slow, that, I can promise, you have to do a lot of looping through your points, it's not really worth it …
http://vimeo.com/user2522760 [vimeo.com]
http://stormbornvfx.com/ [stormbornvfx.com]
Manuel Tausch
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jjayakumar
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I have a complex scene file where the user selects only few primitives using the bounding box and exports only objects containing those primitives. To get the list of objects inside, I use the extendedGroup to extend points to primitive objects. Any method that iterates over each and every primitive is really slow. so I'm trying to find a workaround for this.

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-J
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buki
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hi!

maybe i dont understand the problem correctly, but this is a way of selecting connected geometry, here i'm doing a preselect, then extend that selection to only connected geometry.

examine the 2 green group SOPs

make sure you have enough edge depth on the second group sop

move the first group SOPs bounding box to play around with selelection
Edited by - July 19, 2012 11:25:15

Attachments:
extendedgroup_182_1.hip (175.5 KB)

daniel bukovec | senior fx td | weta digital
qLib -- http://qlab.github.io/qLib/ [qlab.github.io]
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asnowcappedromance
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luckily enough you know which points/prims are connected to the bound group so you can easily do a point cloud lookup which is as fast as it can get in Houdini. I attached a file, maybe this one's the solution for you.

Attachments:
extendedgroup_pcOpen_Manu.hip (158.3 KB)

http://vimeo.com/user2522760 [vimeo.com]
http://stormbornvfx.com/ [stormbornvfx.com]
Manuel Tausch
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jjayakumar
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Thanks for the solution guys. I'm still working on it. Hopefully it speeds up the extension process.


Thanks
-J
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