<strong>OpenSCAD</strong> is an open-source computer-aided design (<abbrtitle="computer-aided design">CAD</abbr>) software application with its own built-in programming-language.
Unlike many other <abbrtitle="computer-aided design">CAD</abbr> software applications which use a <abbrtitle="graphical user interface">GUI</abbr> to create, edit, and manipulate objects, <strong>OpenSCAD</strong> creates, edits, and manipulates objects via a scripting programming-language.
<strong>OpenSCAD</strong> scripts are usually stored in <code>.scad</code> files.
</p>
<p>
<strong>OpenSCAD</strong> includes many features similar to many imperative programming-languages; including:
</p>
<ul>
<li>variables,</li>
<li>control structures (such as if-statements and loops),</li>
<li>modules, and</li>
<li>libraries.</li>
</ul>
<p>
For those already familiar with programming-languages such as C, C++, C#, D, Dart, Go, Java, JavaScript, PHP, and others — <strong>OpenSCAD</strong> uses curly-brackets.
One basic 3D shape that <strong>OpenSCAD</strong> provides built-in support for is the <strong>cuboid</strong>.
</p>
<p>
To create a <strong>cuboid</strong> use the <code>cube</code> command.
For example:
</p>
<figure>
<pre><code>
cube([50,75,100]);
</code></pre>
</figure>
<p>
The parameter to the <code>cube</code> command specifies the <em>width</em>, <em>length</em>, and <em>height</em> of the <strong>cuboid</strong>.
Note that the <code>cube</code> command will put one corner of the <strong>cuboid</strong> at the origin — <code>[0,0,0]</code>.
</p>
</section>
<section>
<h2>Spheres</h2>
<p>
Another basic 3D shape that <strong>OpenSCAD</strong> provides built-in support for is the <strong>sphere</strong>.
</p>
<p>
To create a <strong>sphere</strong> use the <code>sphere</code> command.
For example:
</p>
<pre><code>
sphere(20);
</code></pre>
<p>
The paraemter to the <code>sphere<code> command specifies the <em>radius</em> of the <strong>sphere</strong>.
Note that the <code>sphere<code> command will put the center of the <strong>sphere</strong> at the origin — <code>[0,0,0]</code>.
</p>
</section>
<section>
<h2>Cylinders, Cones, and Truncated Cones</h2>
<p>
Three other basic 3D shape that <strong>OpenSCAD</strong> provides built-in support for is the <strong>cylinder</strong>, the <strong>cone</strong>, and the <strong>truncated cone</strong>.
</p>
<p>
To create a <strong>cylinder</strong>, <strong>cone</strong>, or <strong>truncated cone</strong> use the <code>cylinder</code> command.
For example, this is a <strong>cylinder</strong>:
</p>
<pre><code>
cylinder(h=50, r1=20, r2=20);
</code></pre>
<p>
Note that <code>r1</code> and <code>r2</code> have the same value.
When <code>r1</code> and <code>r2</code> have the same value, you get a <strong>cylinder</strong> (rathe than a <strong>cone</strong> or a strong>truncated cone</strong>).
</p>
<p>
And, for example, this is a <strong>cone</strong>:
</p>
<pre><code>
cylinder(h=50, r1=20, r2=0);
</code></pre>
<p>
In that example, <code>r2</code> is zero.
But having <code>r1</code> be zero (and <code>r2</code> not be zero) would also produce a <strong>cone</strong>.
</p>
<p>
And, for example, this is a <strong>truncated cone</strong>:
</p>
<pre><code>
cylinder(h=50, r1=20, r2=5);
</code></pre>
<p>
In that example, <code>r2</code> is smaller than <code>r1</code> (and neither is zero).
But having <code>r1</code> be smaller than <code>r2</code> would also be a <strong>truncated cone</strong>.
</p>
<p>
Note that the <code>cylinder<code> command will put the center of one end of the bottom circle at the origin — <code>[0,0,0]</code>.
By default, a <strong>sphere</strong> is centered at the origin — <code>[0,0,0]</code>.
However, <strong>cuboids</strong>, <strong>cylinders</strong>, <strong>cones</strong>, and <strong>truncated cones</strong> are <em>not</em>, by default, cetered at the origin.
</p>
<p>
To make it so <strong>cuboids</strong>, <strong>cylinders</strong>, <strong>cones</strong>, and <strong>truncated cones</strong> are centered at the origin, use the <code>center=true</code> paramter.
