diff --git a/src/experimental/tri_circle_packing.scad b/src/experimental/tri_circle_packing.scad
index d4b74b75..560b4d57 100644
--- a/src/experimental/tri_circle_packing.scad
+++ b/src/experimental/tri_circle_packing.scad
@@ -14,7 +14,7 @@ function c3_a(r1, r2, r3) =
     acos((b ^ 2 + c ^ 2 - a ^ 2) / (2 * b * c));
 
 
-function pack_one(min_r, center, sinv, leng_cv, unit_cv, pre_leng, pre_r) = 
+function pack_one(min_r, center, v, sinv, leng_cv, unit_cv, pre_leng, pre_r) = 
             let(
                 r2 = r2(sinv, leng_cv, pre_leng),
                 leng = pre_leng + r2,
@@ -23,13 +23,13 @@ function pack_one(min_r, center, sinv, leng_cv, unit_cv, pre_leng, pre_r) =
                 r3 = c3_r(pre_r, r2),
                 a = c3_a(pre_r, r2, r3),
                 vta = unit_cv * (r3 + r2),
-                r3_ct1 = r2_ct + ptf_rotate(vta, a),
-                r3_ct2 = r2_ct + ptf_rotate(vta, -a)           
+                r3_ct1 = r2_ct + ptf_rotate(vta, a, v),
+                r3_ct2 = r2_ct + ptf_rotate(vta, -a, v)           
             )
             r2 > min_r ? 
                 concat(
                     [[r2_ct, r2], if(r3 > min_r) each [[r3_ct1, r3], [r3_ct2, r3]]], 
-                    pack_one(min_r, center, sinv, leng_cv, unit_cv, r2 + leng, r2)
+                    pack_one(min_r, center, v, sinv, leng_cv, unit_cv, r2 + leng, r2)
                 )
                 : [];
 
@@ -39,7 +39,9 @@ function tri_circle_packing(shape_pts, min_r) =
         s1 = shape_pts[1] - shape_pts[0],
         s2 = shape_pts[2] - shape_pts[1],
         s3 = shape_pts[0] - shape_pts[2],
-        R = abs(cross(s1, s2)) / (norm(s1) + norm(s2) + norm(s3)),
+        cross_value = cross(s1, s2),
+        nv = is_num(cross_value) ? [0, 0, cross_value] : cross_value,
+        R = abs(norm(nv)) / (norm(s1) + norm(s2) + norm(s3)),
 
         ca = center - shape_pts[0],
         leng_ca = norm(ca),
@@ -58,8 +60,8 @@ function tri_circle_packing(shape_pts, min_r) =
     )
     [
         [center, R], 
-        each pack_one(min_r, center, sina, leng_ca, unit_ca, R, R), 
-        each pack_one(min_r, center, sinb, leng_cb, unit_cb, R, R), 
-        each pack_one(min_r, center, sinc, leng_cc, unit_cc, R, R), 
+        each pack_one(min_r, center, nv, sina, leng_ca, unit_ca, R, R), 
+        each pack_one(min_r, center, nv, sinb, leng_cb, unit_cb, R, R), 
+        each pack_one(min_r, center, nv, sinc, leng_cc, unit_cc, R, R), 
     ];    
     
\ No newline at end of file