Dear openscad community i have a rather simple script (less than 10 lines) which shows correctly with F5 in about 4 seconds, but fails to render with F6 (no result after about two hours). I'm using version openscad 2021.01 on OS: Ubuntu 18.04.6 LTS x86_64, Kernel: 5.4.0-120-generic r_min = 164; r_max = 179; difference(){   translate([0,0,-5])   cube([400,400,10], center=true);     for(i=[-500:1.6:500], j=[-500:1.6:500])       if(r_min ^2 < (j*sin(60))^2 + (i+j*cos(60))^2 && (j*sin(60))^2 + (i+j*cos(60))^2 < r_max ^2)         translate([j*sin(60),i+j*cos(60),-.4])         cylinder($fn = 6, h = .6, r1 = .6, r2 = .8); } Preview correctly shows: What changes could make F6 possible? Thank you very much and best regards Orkus