SVG files exported from CAD programs — especially ones that have been round-tripped through a DXF import in Inkscape — are often full of junk that crashes SVG parsers. The SVG cleaner strips that junk so your outlines load cleanly.
What goes wrong with CAD SVGs
Common culprits the cleaner removes:
<symbol id="*Model_Space">blocks — the asterisk is an invalid XML id character that crashes parsers.<inkscape:path-effect>live path effects.<pattern id="Hatch…">DXF hatch fills.<marker id="Distance…">dimension markers.- Unused
<defs>entries and strayxml:space="preserve".
Two ways to use it
- Automatic — cncfoam.com cleans every SVG the moment you load or drop it into the tool, showing a toast of what was stripped. You usually never need to think about it.
- The standalone tool — the public SVG cleaner page cleans files in your browser (nothing is uploaded). Drop a single file or a whole folder; each file gets a CLEANED / ALREADY CLEAN / FAIL badge with the exact parser message, and you can download everything as a ZIP.
Security
SVGs can carry scripts, so every SVG that enters cncfoam.com is also sanitised — <script>, <foreignObject>, event handlers and javascript:/data: links are stripped — before it is parsed or stored. The cleaner is about parseability; the sanitiser is about safety; both run automatically.
If an SVG refuses to load anywhere — not just in cncfoam.com — run it through the cleaner first. It fixes a surprising number of "why won't this open" files.