@Override
    public void set(Vector3f v1, Vector3f v2, Vector3f v3) {
        center = null;
        normal = null;

        pointA.set(v1);
        pointB.set(v2);
        pointC.set(v3);
    }
Alters the locations of all 3 vertices and deletes the stored centroid
and normal.

@param v1 the desired location of the first vertex (not null, unaffected)
@param v2 the desired location of the 2nd vertex (not null, unaffected)
@param v3 the desired location of the 3rd vertex (not null, unaffected)
jme3-core/src/main/java/com/jme3/math/Triangle.java