Why are inflections bad?



  • Jeff Peters
    Is it bad if there are very small inflections, under 5pt? I can't add point to some of my Beziers without breaking the roundness of the design.

    Actually, you can. You just set your other points higher up in the curve, like you did on the form to the right.
  • Jens Kutilek
    This last example is not an inflection point but an extremum point (as are a couple of the earlier examples in this thread).
  • Vasil Stanev
    I did a test export of my Ornatis :) to see how it looks in Adobe Illustrator, and to my surprise, despite much attention to detail the Beziers still look bumpy at some places.

    I do not know exactly if it is a feature of exporting to TTF in FL5 or if it is due to squeezing the font in under 700 pt hight, but even if I slightly disrespect the rule of the golden triangle and/or have an inflection, the program gets a mind of its own how to render it. I was unable to export an OTF.
    So, this is a way, in my particular case, in which inflections are bad.
  • Thomas Phinney
    @Vasil Stanev
    That is all about PS > TT curve conversion, with integer units, of very fine details relative to the UPM. The problems occur regardless of inflections. The lower circled problem has no inflection, and other bulges and irregularities are occurring without inflections.

    Those tick marks in your glyph window are only 10 units apart. Regardless of tool, that is a tricky situation with that level of detail, and changing font formats.

    You might try:
    • increasing your UPM
    • using OTF instead of TTF so as to avoid the curve conversion
    • converting your curves to TTF in the font editor and then manually fixing them up (painful, but FLS 5 does support TT editing) 
    • do the same export in FontLab VI instead of 5 (better built-in TT conversion)

  • Vasil Stanev
    @Thomas Phinney Thank You for the input, will try some of these methods out. Most probably increasing the UPM.
  • Thomas Phinney
    Where I wrote “changing font formats” I could have written more specifically “changing the glyph curve format.”

    In *theory* you can go from TrueType to PostScript curves losslessly. That is, the math converts cleanly. But even that is subject to rounding error if the curves have to be constrained to the grid.

    (FontLab VI offers you the option of higher precision at output time with PS curves, but that comes with the cost of larger font file size.)

    But going from PostScript to TrueType is not inherently lossless.

    And worse, going either direction is normally subject to rounding error for the off-curve points. If your curve details are so fine that you are working close to individual grid points... ugh.
  • Chris Lozos
    Chris Lozos Posts: 1,458
    I rarely design a font at less than 2000 UPM any more.