Point Cloud cone angle??

[bhaveshpandey]

hi guys..i am not able to get the cone angle option in the Point cloud open vop to work..I'm sure I have missed something

i need to work on points within a sort of field of view of any given point and I guess I could use cone angle for that..

any suggestions would be great..

here's a simple test file..

cheers

test.hipnc

[anim]

you need to fill in Normal Channel parameter in pcopen with attribute from points which will be compared to this point's normal based on cone angle

as help states: "Points with dot(N, Npoint) > cos(cone) will be queued, and unmatched points will be rejected."

so it's probably not what you've expected, it's still searching full sphere radius and then its filtering points based on the angle between their normal and provided query normal as opposed to searching only in cone angle

[sanostol]

but You can filter them on Your own, just get the dotproduct between the direction You want, and the normalized differenz of the pointposition and the found pointposition. the dotproduct's values are from 1 to -1

1 means same direction, 0 means 90 degree, and -1 is opposit direction

[bhaveshpandey]

thanks guys!!

@anim I did read the help docs but it was a bit confusing..

@sanostol is that what happens under the hood? (or there's any optimized implementation related to the cone angle??)

because the point count for the effect would be pretty high..

[Macha]

but You can filter them on Your own, just get the dotproduct between the direction You want, and the normalized differenz of the pointposition and the found pointposition. the dotproduct's values are from 1 to -1

1 means same direction, 0 means 90 degree, and -1 is opposit direction

But then you are supplying the vector after the point is found whereas you need it before. Or did I misunderstand his original question?

Edited January 16, 2011 by Macha

[sanostol]

yes, you filter after that on Your own on the found points. But the pointcloud functions are very fast even on huge pointclouds. If You throw them away early in the loop it should be acceptable

Edited January 16, 2011 by sanostol

[bhaveshpandey]

thanks guys..i have setup a while loop with point clouds for now and i'm getting what i expected but if there's any way to get it to work (the cone angle to filter out the points) that would be great..i feel the Point Cloud Open node's cone angle option should have some optimisation in terms of computation..

cheers