Nearest point with colour above a certain value

[michaelb-01]

I posted here (http://forums.odforce.net/topic/20626-flipping-animation/) yesterday but haven't yet received any replies so I will ask a more basic question that should help me solve the problem in my other post.

 

If I have a grid of black points and I colour some of them red, how can I find the nearest red point for the other (black) points. I'm fairly sure it would be:

 

- pcopen

- pciterate

- if red is > 0.1

 

But then how would I break out of the pciterate and use that found point, e.g. to get the distance between the found red point and the current black point?

 

Cheers,

Mike

[rayman]

something like this?

float thr = .1;
int maxDst = 5;
int maxPts = 30;
int clRed = -1;
int pthandle = pcopen(0, "P", @P, maxDst, maxPts);
while(pciterate(pthandle)){
    vector ptCd;
    pcimport(pthandle,"Cd",ptCd);
    int ptIx;
    pcimport(pthandle,"point.number",ptIx);
    if(ptCd.x>thr){
        clRed = ptIx;
        break;
    }
}
pcclose(pthandle);
if(clRed>-1){
    vector distVec = point(0,"P",clRed);
    float dist = length(distVec-@P);
    i@clPt = clRed;
    f@redDst = dist;
}

Edited July 30, 2014 by rayman

[michaelb-01]

That looks like it should work! Thanks Pavel i'll try it now!

[michaelb-01]

That works great! However i'm using a foreach sop to iterate over the primitives so I need to find the nearest red point in one of the primitives (that doesnt exist inside the foreach sop) so i'm trying to reference a node above it but now i'm just getting 0 for the redDst attribute.. any ideas what i'm doing wrong? Here's the basic hip file im testing with:

 

https://dl.dropboxusercontent.com/u/18098614/triangle_flip_v3.hip

 

Thanks for your help,

Mike

[Annon]

PCFilter and get P.

 

If you use pcImport you can get the distance or the point number of the point it's iterating on as well.

http://www.sidefx.com/docs/houdini13.0/nodes/vop/pcimport

[michaelb-01]

Thanks for the advice, I have it pretty much working now but the rotation is behaving slightly odd, each primitive starts to rotate in one direction then (I think) at 90 degrees it flips to the other side... Is there a problem with my rotation vop sop?

 

https://dl.dropboxusercontent.com/u/18098614/triangle_flip_v3.hip

 

Thanks,

Mike

[wateryfield]

That works great! However i'm using a foreach sop to iterate over the primitives so I need to find the nearest red point in one of the primitives (that doesnt exist inside the foreach sop) so i'm trying to reference a node above it but now i'm just getting 0 for the redDst attribute.. any ideas what i'm doing wrong? Here's the basic hip file im testing with:

 

https://dl.dropboxusercontent.com/u/18098614/triangle_flip_v3.hip

 

Thanks for your help,

Mike

I created a simple vopsop to find the nearest red point for each  black points.

Hope it help.

find_near_point.hip

Edited July 30, 2014 by wateryfield

[michaelb-01]

Hey I dont think the file attached properly? I got that working thanks Pavel's code if you take a look at my hip file posted above (https://dl.dropboxus...gle_flip_v3.hip)

 

Cheers

[michaelb-01]

I just went through your file and its very helpful. Thanks!