title: Trouble with font and text extrusion
body: <p>So, I'm doing some odd things with text extrusion and (perhaps not surprisingly) having some odd issues in OpenSCAD.</p>
  <p>This is part of a much larger project, but I've been able to simplify the problem down to the following snippet of code.</p>
  <pre><code>use&lt;RingbearerMedium-51mgZ.ttf&gt;
  
  Text = &quot;b&quot;;
  Font = &quot;Ringbearer:style=Medium&quot;;
  segment_count = 2;
  segment_width = 2;
  text_height = 5;
  text_thickness = 1;
  
  // Iterate over each &quot;segment&quot; of text
  for (segment_number = [0: segment_count - 1])
  {
      // Calculate the x offset of the current &quot;segment&quot; of text
      segment_x_offset = segment_number * segment_width;
  
      // Extrude the &quot;segment&quot; of text to the requested thickness
      linear_extrude(text_thickness)
  
      // Grab the current &quot;segment&quot; of text
      intersection()
      {
          text(Text, font=Font, size=text_height);
          translate([segment_x_offset, 0])
              square([segment_width, text_height]);
      }
  }
  </code></pre>
  <p>All this does is generate a line of text (just &quot;b&quot;, in this case), cuts it into &quot;segments&quot;, then extrudes each segment in-place.  It's not much use in this example, but in the larger one, I'm translating and rotating each segment.</p>
  <p>OpenSCAD's F5 preview renders fine.  Here's a screenshot:</p>
  <p><a href="https://i.stack.imgur.com/e0WFg.png" rel="nofollow noreferrer">F5 Preview</a></p>
  <p>However, the F6 preview always drops the left side of the letter &quot;b&quot; and displays the error &quot;ERROR: The given mesh is not closed! Unable to convert to CGAL_Nef_Polyhedron&quot;.  Here's a screenshot:</p>
  <p><a href="https://i.stack.imgur.com/AdOom.png" rel="nofollow noreferrer">F6 Preview</a></p>
  <p>This effects other letters as well, but only seems to be a problem with the &quot;Ringbearer&quot; font I'm trying to use.  I don't know if I can upload the font, but it's available for download for free from here: <a href="https://www.fontspace.com/ringbearer-font-f2246" rel="nofollow noreferrer">Link to Ringbearer Font</a>.  Extruding and rendering the font without breaking it into segments works just fine.  It's just when I try to segment this particular font that OpenSCAD fails.</p>
  <p>Now, the obvious answer is to use a font that works, which is fine, as far as it goes, but I'm genuinely curious why this is happening.  Is it an error with the font or is this a limitation of OpenSCAD?  Is this a known issue that I'm just not aware of?</p>
  <p>I appreciate any insight I can get.</p>