diff --git a/docs/lib-in_line.md b/docs/lib-in_polyline2d.md
similarity index 57%
rename from docs/lib-in_line.md
rename to docs/lib-in_polyline2d.md
index 6016b781..bcd3555b 100644
--- a/docs/lib-in_line.md
+++ b/docs/lib-in_polyline2d.md
@@ -1,4 +1,4 @@
-# in_line
+# in_polyline2d
 
 Checks wether a point is on a line.
 
@@ -12,7 +12,7 @@ Checks wether a point is on a line.
 
 ## Examples
 
-    include <in_line.scad>;
+    include <in_polyline2d.scad>;
 
     pts = [
         [0, 0],
@@ -20,7 +20,7 @@ Checks wether a point is on a line.
         [10, 10]
     ];
 
-    echo(in_line(pts, [-2, -3]));  // false
-    echo(in_line(pts, [5, 0]));    // true
-    echo(in_line(pts, [10, 5]));   // true
-    echo(in_line(pts, [10, 15]));  // false
\ No newline at end of file
+    echo(in_polyline2d(pts, [-2, -3]));  // false
+    echo(in_polyline2d(pts, [5, 0]));    // true
+    echo(in_polyline2d(pts, [10, 5]));   // true
+    echo(in_polyline2d(pts, [10, 15]));  // false
\ No newline at end of file
diff --git a/src/__private__/__in_line.scad b/src/__private__/__in_line2d.scad
similarity index 71%
rename from src/__private__/__in_line.scad
rename to src/__private__/__in_line2d.scad
index 8493bfcc..2a96cd69 100644
--- a/src/__private__/__in_line.scad
+++ b/src/__private__/__in_line2d.scad
@@ -1,4 +1,4 @@
-function __in_line(line_pts, pt, epsilon = 0.0001) =
+function __in_line2d(line_pts, pt, epsilon = 0.0001) =
     let(
         v1 = line_pts[0] - pt, 
         v2 = line_pts[1] - pt
diff --git a/src/in_line.scad b/src/in_line.scad
deleted file mode 100644
index ff6995d9..00000000
--- a/src/in_line.scad
+++ /dev/null
@@ -1,10 +0,0 @@
-include <__private__/__in_line.scad>;
-
-function _in_line_sub(line_pts, pt, epsilon, iend, i = 0) = 
-    i == iend ? false : (
-        __in_line([line_pts[i], line_pts[i + 1]], pt, epsilon) ? true :
-            _in_line_sub(line_pts, pt, epsilon, iend, i + 1)
-    );
-
-function in_line(line_pts, pt, epsilon = 0.0001) = _in_line_sub(line_pts, pt, epsilon, len(line_pts) - 1);
-    
\ No newline at end of file
diff --git a/src/in_polyline2d.scad b/src/in_polyline2d.scad
new file mode 100644
index 00000000..1bb179ab
--- /dev/null
+++ b/src/in_polyline2d.scad
@@ -0,0 +1,10 @@
+include <__private__/__in_line2d.scad>;
+
+function _in_polyline2d_sub(line_pts, pt, epsilon, iend, i = 0) = 
+    i == iend ? false : (
+        __in_line2d([line_pts[i], line_pts[i + 1]], pt, epsilon) ? true :
+            _in_polyline2d_sub(line_pts, pt, epsilon, iend, i + 1)
+    );
+
+function in_polyline2d(line_pts, pt, epsilon = 0.0001) = _in_polyline2d_sub(line_pts, pt, epsilon, len(line_pts) - 1);
+    
\ No newline at end of file
diff --git a/src/in_shape.scad b/src/in_shape.scad
index ee7a204b..3617e1b7 100644
--- a/src/in_shape.scad
+++ b/src/in_shape.scad
@@ -1,5 +1,5 @@
 include <__private__/__lines_from.scad>;
-include <__private__/__in_line.scad>;
+include <__private__/__in_line2d.scad>;
 
 function _in_shape_in_line_equation(edge, pt) = 
     let(
@@ -14,7 +14,7 @@ function _in_shape_in_line_equation(edge, pt) =
 
 function _in_shape_in_any_edges_sub(edges, leng, pt, i, epsilon) = 
     leng == i ? false : (
-        __in_line(edges[i], pt, epsilon) ? true : _in_shape_in_any_edges_sub(edges, leng, pt, i + 1, epsilon)
+        __in_line2d(edges[i], pt, epsilon) ? true : _in_shape_in_any_edges_sub(edges, leng, pt, i + 1, epsilon)
     );
 
 function _in_shape_in_any_edges(edges, pt, epsilon) = _in_shape_in_any_edges_sub(edges, len(edges), pt, 0, epsilon);
diff --git a/src/trim_shape.scad b/src/trim_shape.scad
index 5c849dee..f90c8c7e 100644
--- a/src/trim_shape.scad
+++ b/src/trim_shape.scad
@@ -1,12 +1,12 @@
 include <__private__/__line_intersection.scad>;
-include <__private__/__in_line.scad>;
+include <__private__/__in_line2d.scad>;
 include <__private__/__lines_from.scad>;
 
 function _trim_shape_any_intersection_sub(lines, line, lines_leng, i, epsilon) =
     let(
         p = __line_intersection(lines[i], line, epsilon)
     )
-    (p != [] && __in_line(line, p, epsilon) && __in_line(lines[i], p, epsilon)) ? [i, p] : _trim_shape_any_intersection(lines, line, lines_leng, i + 1, epsilon);
+    (p != [] && __in_line2d(line, p, epsilon) && __in_line2d(lines[i], p, epsilon)) ? [i, p] : _trim_shape_any_intersection(lines, line, lines_leng, i + 1, epsilon);
 
 // return [idx, [x, y]] or []
 function _trim_shape_any_intersection(lines, line, lines_leng, i, epsilon) =