Most common causes:
1. The SVG uses `<rect>` / `<circle>` / `<ellipse>` primitives that were NOT converted to paths. In Inkscape: select all → Path → Object to Path → save.
2. The SVG uses gradients / patterns / clip-paths. The tool only parses path geometry. Flatten and simplify.
3. Coordinates are in inches or other non-px units. SVGs work best in millimetres with a viewBox of 0 0 <width> <height>.
4. Path is zero-area (e.g. a single point). Make sure your shape has thickness.
1. The SVG uses `<rect>` / `<circle>` / `<ellipse>` primitives that were NOT converted to paths. In Inkscape: select all → Path → Object to Path → save.
2. The SVG uses gradients / patterns / clip-paths. The tool only parses path geometry. Flatten and simplify.
3. Coordinates are in inches or other non-px units. SVGs work best in millimetres with a viewBox of 0 0 <width> <height>.
4. Path is zero-area (e.g. a single point). Make sure your shape has thickness.