Hello all,

I produced a 3D quadt_strip shape, but not only one row but multiple.

It’s kind of a circle (Moebius strip).

Unfortunately I have a big seam (horizontal right side) I cannot get rid of.

Can someone check my logic please? This gets called from setup() and is shown later.

Chrisir

```
// defining a QUAD_STRIP shape
int i2_span=100;
void initMainItem() {
// https://de.wikipedia.org/wiki/M%C3%B6biusband
boolean grid=false;
moebius1=createShape();
moebius1.beginShape(QUAD_STRIP);
if (grid) {
// only grid
moebius1.noFill();
moebius1.stroke(0);
} else {
// full fill
moebius1.fill(255, 0, 0);
moebius1.noStroke();
}
// i2 -> radius (how wide the red strip is)
// i3 / i -> alpha (angle)
for (int i2=-i2_span; i2<i2_span; i2++) {
for (int i3=0; i3<360+1; i3++) {
int i=i3;
if (i>360)
i=i-360;
makeVertex3D(i2, i);
makeVertex3D(i2+1, i);
//
}//for
//
}//for
// ---------------------------------
/*
for (int i2=-i2_span; i2<i2_span-1; i2+=1) {
float r = i2/i2_span;
float alpha=radians(359);
PVector v = new PVector(
cos(alpha) * ( 1+ ((r/2) * cos ( alpha / 2 ) ) ),
sin(alpha) * ( 1+ ((r/2) * cos ( alpha / 2 ) ) ),
(r/2) * sin(alpha/2));
v.mult(factor1);
v.y+=yadd1;
// moebius1.vertex(v.x, v.y, v.z);
r = (i2+1)/i2_span;
alpha=radians(0);
v = new PVector(
cos(alpha) * ( 1+ ((r/2) * cos ( alpha / 2 ) ) ),
sin(alpha) * ( 1+ ((r/2) * cos ( alpha / 2 ) ) ),
(r/2) * sin(alpha/2));
v.mult(factor1);
v.y+=yadd1;
// moebius1.vertex(v.x, v.y, v.z);
//
}//for
*/
moebius1.endShape();
println("");
println (">>>>"
+leaves.size());
}//func
void makeVertex3D( int i2, int i) {
float factor1=220;
float yadd1= 200;
float r = i2/i2_span;
float alpha=radians(i);
PVector v = new PVector(
cos(alpha) * ( 1+ ((r/2) * cos ( alpha / 2 ) ) ),
sin(alpha) * ( 1+ ((r/2) * cos ( alpha / 2 ) ) ),
(r/2) * sin(alpha/2));
v.mult(factor1);
v.y+=yadd1;
moebius1.vertex(v.x, v.y, v.z);
}
//
```