Trouble with font and text extrusion

Question

So, I'm doing some odd things with text extrusion and (perhaps not surprisingly) having some odd issues in OpenSCAD.

This is part of a much larger project, but I've been able to simplify the problem down to the following snippet of code.

use<RingbearerMedium-51mgZ.ttf>

Text = "b";
Font = "Ringbearer:style=Medium";
segment_count = 2;
segment_width = 2;
text_height = 5;
text_thickness = 1;

// Iterate over each "segment" of text
for (segment_number = [0: segment_count - 1])
{
    // Calculate the x offset of the current "segment" of text
    segment_x_offset = segment_number * segment_width;

    // Extrude the "segment" of text to the requested thickness
    linear_extrude(text_thickness)

    // Grab the current "segment" of text
    intersection()
    {
        text(Text, font=Font, size=text_height);
        translate([segment_x_offset, 0])
            square([segment_width, text_height]);
    }
}

All this does is generate a line of text (just "b", in this case), cuts it into "segments", 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.

OpenSCAD's F5 preview renders fine. Here's a screenshot:

F5 Preview

However, the F6 preview always drops the left side of the letter "b" and displays the error "ERROR: The given mesh is not closed! Unable to convert to CGAL_Nef_Polyhedron". Here's a screenshot:

F6 Preview

This effects other letters as well, but only seems to be a problem with the "Ringbearer" 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: Link to Ringbearer Font. 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.

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?

I appreciate any insight I can get.

Answer 1

Within OpenScad, go to help->font list. I think the font you are using isn't supported.

Yet I had a similar problem with a supported font. I changed the font few times until I found one that works for me well, and look nice as well.

It also depends on the font size. Sometimes same font fails at a smaller size, and works well on a larger size.

Anyway, you can see this on the slicer, before going to the printing. Take a close look at the slicing layers of the text, it will save you some printing time and frustration.