I need a simple way to fix geometries intersections.

[Masoud]

Hi guys,

I'm looking for a (simple and fast) way to fix intersections between geometries. I found this video:

But the problem is the result is not that satisfying.

I would appreciate any ideas.

 

Thanks for helping.

[fencer]

Quote

But the problem is the result is not that satisfying.

This doesn't give us any information about you issue, show your "not satisfying" result, share setup or example...
The setup from the video is working as expected, tested.

[Librarian]

Have Some points and pscale att on those use this after

//get neighbour pts finding a arrary
int nPts[] = nearpoints(geoself(), @P, chf("maxdist"), chi("maxpts"));
pop(nPts, 0);
i[]@nPts = nPts;
i@id = @ptnum;
matrix mArray[];
float targetD[];

foreach(int pt; nPts){
    float nRadius = point(geoself(), "pscale", pt);
    vector nPos = point(geoself(), "P", pt);
    float myRadius = @pscale;
    vector myPos = @P;
    float distance = distance(nPos,myPos);
    float collideLength = nRadius + myRadius;
    
    if ( distance < collideLength){
        //intersectNums += 1;
        //set localMatrix[] by nearPoints
        vector z = normalize(nPos - myPos);
        vector x = normalize( cross(set(0,1,0), z));
        vector y = cross(z, x);
        matrix m = set(x,y,z, myPos);
        m.xw = 0.0;
        m.yw = 0.0;
        m.zw = 0.0;
        append(mArray, m);
        
        //calculate intersect distance
        float intersectD = (pow(myRadius, 2) - pow(nRadius, 2) + pow(distance, 2)) / (2.0 * distance);
        append(targetD, intersectD);
    }
}
4[]@mArray = mArray;
f[]@targetD = targetD;

then copy to points and than use this
 

//foreach neighbour pts and check if the point sphere intersect with another guy
int nPts[] = i[]@nPts;
float targetD[] = point(1, "targetD", i@id);
matrix mArray[] = point(1, "mArray", i@id);

//set deform weight 
float weight = 0;
foreach(int i; int pt; nPts){
        
        //calculate intersect distance
        float intersectD = targetD[i];
        //check if the Pt Pos > myRadius
        matrix m = mArray[i];
        vector newPos = @P * invert(m);
        if( newPos.z > intersectD){
            vector pos = newPos;
            pos = set(pos.x, pos.y, intersectD);
            @P = pos * m;
            weight = 1;
        }
        //weight = fit(newPos.z, -f@pscale, intersectD + chf("weight_offset"), 0, 1);   

   
}
//f@weight = weight;
f@weight = chramp("weight_ramp", weight);

then blur weight Play with Code and Setup...

 

[hannes603]

@Librarian    

 

he sad , something simple XD

love it 

[tamagochy]

On 12/29/2022 at 8:30 AM, Librarian said:

Have Some points and pscale att on those use this after

//get neighbour pts finding a arrary
int nPts[] = nearpoints(geoself(), @P, chf("maxdist"), chi("maxpts"));
pop(nPts, 0);
i[]@nPts = nPts;
i@id = @ptnum;
matrix mArray[];
float targetD[];

foreach(int pt; nPts){
    float nRadius = point(geoself(), "pscale", pt);
    vector nPos = point(geoself(), "P", pt);
    float myRadius = @pscale;
    vector myPos = @P;
    float distance = distance(nPos,myPos);
    float collideLength = nRadius + myRadius;
    
    if ( distance < collideLength){
        //intersectNums += 1;
        //set localMatrix[] by nearPoints
        vector z = normalize(nPos - myPos);
        vector x = normalize( cross(set(0,1,0), z));
        vector y = cross(z, x);
        matrix m = set(x,y,z, myPos);
        m.xw = 0.0;
        m.yw = 0.0;
        m.zw = 0.0;
        append(mArray, m);
        
        //calculate intersect distance
        float intersectD = (pow(myRadius, 2) - pow(nRadius, 2) + pow(distance, 2)) / (2.0 * distance);
        append(targetD, intersectD);
    }
}
4[]@mArray = mArray;
f[]@targetD = targetD;

then copy to points and than use this
 

//foreach neighbour pts and check if the point sphere intersect with another guy
int nPts[] = i[]@nPts;
float targetD[] = point(1, "targetD", i@id);
matrix mArray[] = point(1, "mArray", i@id);

//set deform weight 
float weight = 0;
foreach(int i; int pt; nPts){
        
        //calculate intersect distance
        float intersectD = targetD[i];
        //check if the Pt Pos > myRadius
        matrix m = mArray[i];
        vector newPos = @P * invert(m);
        if( newPos.z > intersectD){
            vector pos = newPos;
            pos = set(pos.x, pos.y, intersectD);
            @P = pos * m;
            weight = 1;
        }
        //weight = fit(newPos.z, -f@pscale, intersectD + chf("weight_offset"), 0, 1);   

   
}
//f@weight = weight;
f@weight = chramp("weight_ramp", weight);

then blur weight Play with Code and Setup...

 

Can you post scene. This code doesnt work for me.

Thanks

[Librarian]

@tamagochy
 

[hannes603]

it does work quiet greatly!

keep it up!

intersection_fix_geo_wrangle.hip