Added source code

utils/core/clip.scad

@@ -0,0 +1,49 @@
+//
+// NopSCADlib Copyright Chris Palmer 2018
+// nop.head@gmail.com
+// hydraraptor.blogspot.com
+//
+// This file is part of NopSCADlib.
+//
+// NopSCADlib is free software: you can redistribute it and/or modify it under the terms of the
+// GNU General Public License as published by the Free Software Foundation, either version 3 of
+// the License, or (at your option) any later version.
+//
+// NopSCADlib is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+// without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+// See the GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License along with NopSCADlib.
+// If not, see <https://www.gnu.org/licenses/>.
+//
+
+//
+//! Construct arbirarily large box to partition 3D space and clip objects, useful for creating cross sections to see the inside when debugging.
+//!
+//! Original version by Doug Moen on the OpenSCAD forum
+//
+//
+module box(xmin, ymin, zmin, xmax, ymax, zmax) //! Construct a box given its bounds
+    polyhedron(
+        [[xmin, ymin, zmin],  // 0
+         [xmin, ymin, zmax],  // 1
+         [xmin, ymax, zmin],  // 2
+         [xmin, ymax, zmax],  // 3
+         [xmax, ymin, zmin],  // 4
+         [xmax, ymin, zmax],  // 5
+         [xmax, ymax, zmin],  // 6
+         [xmax, ymax, zmax]], // 7
+        [[7,5,1,3],  // top
+         [2,0,4,6],  // bottom
+         [5,4,0,1],  // front
+         [3,2,6,7],  // back
+         [5,7,6,4],  // right
+         [0,2,3,1]]  // left
+    );
+
+module clip(xmin = -inf, ymin = -inf, zmin = -inf, xmax = inf, ymax = inf, zmax = inf) //! Clip child to specified boundaries
+    render() intersection() {
+        children();
+
+        box(xmin, ymin, zmin, xmax, ymax, zmax);
+    }