v@pt = point("../transform1/", "P" , 0);

int is_pt_grp = inpointgroup(0, "pt_starter", @ptnum);

if (is_pt_grp==1)
{
        
        int src = @ptnum;
        int end_pt= -1; //-1 so the first loop can start
        int pt = src; //destination point and source to look which edge is unshared

        int loop[]; // border loop array
        int unshared_edge;
        int unshared_edge_check = -1;

        while (src != end_pt)//the loop will run untill it finds an unshared edge with a destination point that equals our first source point
        {
            setpointgroup(0, "loop", pt, 1, "set");
            unshared_edge = pointhedge(0, pt);
            unshared_edge_check = hedge_equivcount(0, unshared_edge);// either 1 or 2

            //Goes to the next half edge with the same source point, until it finds an edge that doesn't have an equivalent -it's unshared/border edge
            while (unshared_edge_check != 1)
            {
                unshared_edge = pointhedgenext(0, unshared_edge);
                unshared_edge_check = hedge_equivcount(0, unshared_edge);
            } 

            append(loop, pt);
            pt = hedge_dstpoint(0, unshared_edge);//to carry on the loop
            end_pt = pt; //this will stop the loop if true
            

        }
        
}

i@id = @ptnum;