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@@ -46,7 +46,7 @@ for (a =[x1,x2,x3]){echo(a);}
 </code></pre>
 	</figure>
 	<p>
-		<strong>OpenSCAD</strong> provides two main methods for 3D modeling:
+		<strong>OpenSCAD</strong> provides two main methods for 3D-modeling:
 	</p>
 	<ul>
 		<li>creating complex object from combinations of simpler shapes, and</li>
@@ -56,6 +56,24 @@ for (a =[x1,x2,x3]){echo(a);}
 		<strong>OpenSCAD</strong> is especially geared towards mechanical, rather than artistic, aspects of 3D computer-aided design.
 		Thus <strong>OpenSCAD</strong> can be useful when one wants to create a model that one wants to 3D-print.
 	</p>
+	<section>
+		<h2>Units</h2>
+		<p>
+			All dimensions in <strong>OpenSCAD</strong> are measured in (the somewhat confusingly named) "unit".
+		</p>
+		<p>
+			The <em>convention</em> used by a lot of people doing 3D-printing is:
+		</p>
+		<figure>
+			1 unit = 1 millimeter
+		</figure>
+		<p>
+			But <strong>OpenSCAD</strong> is in a sense unit-less.
+		</p>
+		<p>
+			And it is a good idea to explicitly size your model when preparing it for 3D-printing.
+		</p>
+	</section>
 </article>
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