How to Fix PDF Font Issues in AutoCAD: Why Your Text Becomes Symbols

Converting engineering drawings from PDF to DXF is often a smooth process—until you open the file in AutoCAD and find that your beautiful annotations have turned into a mess of question marks, squares, or weird symbols.

This is one of the most common complaints in the AEC industry. In this guide, we'll explain why this happens and how to fix it once and for all.

1. The "SHX" vs "TrueType" Problem

The root of the problem lies in how AutoCAD handles text. Historically, AutoCAD uses SHX fonts, which are actually defined as collections of vector lines rather than characters. When you export a drawing to PDF, newer versions of AutoCAD try to be "smart" by embedding these SHX fonts as hidden comments.

However, when a standard converter reads that PDF, it doesn't see "Text"; it sees a bunch of tiny lines that look like a letter. The result? A DXF file where the letter "A" is just 3 separate lines, and you can't edit the numerical value of your dimensions.

2. How pdf2dxf.us Solves This

Our conversion engine at pdf2dxf.us uses an advanced OCR (Optical Character Recognition) layer combined with vector path analysis. Instead of just tracing lines, we try to reconstruct the text entities:

• Character Recognition: We detect common engineering fonts and map them to standard DXF TEXT entities.
• Scale Awareness: We keep the text size relative to your drawing scale.
• Layer Integrity: Text is kept on its original layer, so you can toggle annotations on and off easily.

3. AutoCAD Settings You Should Check

If you've converted a file and the text still looks off, check these internal AutoCAD variables:

• FONTALT: This variable controls the alternative font used when a font file is missing. Set it to simplex.shx or arial.ttf.
• PDFSHX: When creating PDFs in AutoCAD, set this to 0 to avoid the creation of those annoying "SHX comments" that confuse most converters.

4. Pro Tip: Use the 'Include Text Layer' Option

When using our converter, make sure the "Include text layer" checkbox is checked. This enables our most advanced text-reconstruction algorythms designed specifically for engineering notation.