How to Fix Slow PDFs Caused by AutoCAD SHX Text Comments
Question details
Users experience significant lag and slow performance when viewing PDFs exported from AutoCAD due to SHX text being converted into comments.
- Product
- Adobe Acrobat / PDF Editors
- Device & OS
- not provided
- Scenario
- Panning, scrolling, or reviewing a PDF document exported from AutoCAD.
- Observed behavior
- The PDF renders and responds extremely slowly because of numerous SHX text elements saved as comment annotations.
Ensure you create a backup copy of your original PDF before applying any flattening or comment-removal techniques, as these actions are generally irreversible and may remove selectable text.
Re-export the PDF from AutoCAD without SHX Comments
The most effective way to prevent this issue is to adjust the PDF export settings directly within AutoCAD.
By disabling the conversion of SHX fonts to PDF comments during the export process, you can maintain standard document performance.
Launch AutoCAD and open the original drawing file (.dwg) that is causing the slow PDF output.
Type 'EPDFSHX' into the AutoCAD command line and press the Enter key.
Change the value from 1 to 0 to disable the export of SHX text as comments.
Proceed to plot or export your drawing to PDF as usual. The resulting file will no longer contain the heavy text comments.
Flatten the PDF or Remove Comments
If you do not have access to the original AutoCAD file, you can strip the SHX comments using a PDF editor.
View and Optimize Heavy PDFs with WPS Office
WPS PDF provides a lightweight and highly responsive environment for opening large or complex PDFs, including those exported from AutoCAD. You can easily manage comments or flatten documents to boost reading performance.
- 1. Open the file: Launch WPS Office and open your slow PDF file using WPS PDF.
- 2. Access comments: Click on the 'Comment' tab to access the comments panel on the side.
- 3. Remove unwanted text comments: Select the SHX text comments that are causing the lag and press the Delete key.
- 4. Flatten the document: To flatten the document, go to 'Menu' > 'Print', select 'WPS PDF' as your printer, and click 'Print' to save a clean, flattened version.
Frequently Asked Questions
Why does AutoCAD export text as comments in PDFs?
AutoCAD exports SHX fonts as comments by default so that the text remains searchable in the resulting PDF. However, thousands of individual comments can cause severe performance issues in standard PDF viewers.
Can I fix this issue without the original AutoCAD DWG file?
Yes, you can fix it by using a PDF editor to bulk-delete the comment annotations, or by printing the PDF to a new virtual PDF file (flattening). Note that these methods may remove the text's searchability.
Does flattening a PDF reduce its file size?
Flattening can reduce file size and significantly improve rendering speed by merging complex layers and annotations, such as thousands of SHX text comments, into a single background layer.
