Procedurally reverse polygons

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Hey everyone,

first of all, I'm sorry if this question has been answered already. I gave my best searching the forums, but I couldn't find an answer.

So, I'm rather new to Houdini and I ran into a problem the other day, that I can not come up with a solution for.
I imported a set of curves from OSM data, but when I use the Ends SOP to close those curves into polygons, they're oriented kinda
randomly. Is there any quick way to make all of them face upwards?

I added a picture for details and would be really greatful, if some of you experts could point me in the right direction!

Cheers and thanks,
Gregor

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Houdini_Polygons.jpg (113.8 KB)

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Hey Gregor,

in your scenario, you can easily create a group by normal. Group all polygons with a normal vector facing -Y. Then you can apply a reverse node to that group.

Cheers
CYTE
Edited by CYTE - 2021年7月15日 11:04:20
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Hey CYTE,

thanks so much for pointing out this possible solution.
Unfortunately, I'm like really new to Houdini, so could you elaborate a little further on how I would go about that?

Thanks so much!

Cheers,
Gregor
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GregorZimmermann
Unfortunately, I'm like really new to Houdini, so could you elaborate a little further on how I would go about that?

Upload your .hip file so that we can show you.
>>Kays
For my Houdini tutorials and more visit:
https://www.youtube.com/c/RightBrainedTutorials [www.youtube.com]
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ALWAYS try to work things out using an EXTREMELY simplified setup (yeah i know
sometimes it's not possible but....try)

so if you set up a bunch of simple square blocks randomly flipped you'd be more confident in dealing with it rather than....ooooooohhhh nooooo what is is this massive mess from OSM..it's too
technical for me.....too many different shapes, too much on the screen I can't deal with it..

NO!!! it's just a bunch of simple squares...

(in the fixme group, you'lll see there's a tolerance of 20deg spread angle...for hilly bits coz despite what many say, the earth is NOT completely flat)

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Screenshot 2021-07-18 065821.jpg (40.6 KB)
flip.hipnc (106.2 KB)

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Hey Vusta,

wow, thank you so much for your file and the super easy solution! Works like a charm.
For some reason the notification mail went straight to my spam folder, so I didn't check the thread for a couple of days.

Thanks so much for everyone involved for your quick and on-point help!
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