# Surface Intersection

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Hi

How would it be possible to detect point,edges or primitives of a surface intersecting with itself and group them?

For two different geometries its easy but for one I dont have idea how to aproach this?

thanks

z

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so what does this mean that its impossible to do,

nobody didnt do it or its just a sleepy week?

this might be very useful I was watching those surfs up articles at awn

http://surfsup.awn.com/?type=article&artID=3

and sea wave geometry is emitting particles for foam on the edge but when it colapses with itself we need a splash?

so i need to get intersection points

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i don't think it is straight forward. which is probably why no one has responded

there might be a POP method to do this.. but I'm not a POP person.. SOP wise.. unless you make something by yourself (SOP or VOPSOP) I can't think of a clean method do this.. even in VOPs you would need to traverse the entire geometry to figure it out (I think)..

good luck

-k

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maybe DOP?.. there must be some sort of "self collision" data...

I'm not really a DOP person tough ... but POP might not be a bad idea indeed..

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yes i know its not easy

will see if somebody has some experience with this

z

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Ah, now that you've told us that its moving, I can think of a way to collide points:

I would assume that you would be able to compute point velocities (possibly using the Trail SOP). So what I'd do here is take those velocities and rename them to N. Now you can feed the same wave geometry into both inputs of a Ray SOP. In the options of the Ray SOP, choose to add points which collide to a Point Group.

Make sense?

Jason

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roughly yes

I will try to set something up

thanks guys

z

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roughly yes

If you struggle at all, I'll throw an example together. Its a three node trick: TrailSOP (compute v) -> AttributeSOP (rename v to N) -> RaySOP (add to group)

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Hi

How would it be possible to detect point,edges or primitives of a surface intersecting with itself and group them?

For two different geometries its easy but for one I dont have idea how to aproach this?

thanks

z

How about peaking the geo by a very small amount and then using a cookie SOP in crease mode to compare the original and peaked geo?

ODF_05454_JSH_find_intersections_using_crease.hip

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• 4 months later...

Hi Jason.

I think I get the basics of what you're saying but I'd love to see an example if you have the time!

Thanks so much.

-Len

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