diff -r 918b6c0f8b5b -r ed9685f44ab3 src/types/boundingbox.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/types/boundingbox.cpp	Sat Dec 14 22:36:06 2019 +0200
@@ -0,0 +1,68 @@
+/*
+ *  LDForge: LDraw parts authoring CAD
+ *  Copyright (C) 2013 - 2019 Teemu Piippo
+ *
+ *  This program 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.
+ *
+ *  This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "boundingbox.h"
+
+BoundingBox& BoundingBox::operator<<(const Point3D& vertex)
+{
+	this->consider(vertex);
+	return *this;
+}
+
+void BoundingBox::consider(const Point3D& vertex)
+{
+	this->minimum.x = std::min(vertex.x, this->minimum.x);
+	this->minimum.y = std::min(vertex.y, this->minimum.y);
+	this->minimum.z = std::min(vertex.z, this->minimum.z);
+	this->maximum.x = std::max(vertex.x, this->maximum.x);
+	this->maximum.y = std::max(vertex.y, this->maximum.y);
+	this->maximum.z = std::max(vertex.z, this->maximum.z);
+}
+
+/*
+ * Returns the length of the bounding box on the longest measure.
+ */
+double longestMeasure(const BoundingBox& box)
+{
+	double dx = box.minimum.x - box.maximum.x;
+	double dy = box.minimum.y - box.maximum.y;
+	double dz = box.minimum.z - box.maximum.z;
+	double size = std::max(std::max(dx, dy), dz);
+	return std::max(std::abs(size / 2.0), 1.0);
+}
+
+
+/*
+ * Yields the center of the bounding box.
+ */
+Point3D center(const BoundingBox& box)
+{
+	return {
+		(box.minimum.x + box.maximum.x) / 2,
+		(box.minimum.y + box.maximum.y) / 2,
+		(box.minimum.z + box.maximum.z) / 2
+	};
+}
+
+/*
+ * Returns the length of the bounding box's space diagonal.
+ */
+double spaceDiagonal(const BoundingBox& box)
+{
+	return distance(box.minimum, box.maximum);
+}