Why Your SVG Imports are Tiny: The Scaling Fix for Affinity, Blender, and Bambu Lab
We’ve all been there. You spend an hour meticulously designing a custom logo or a mechanical part in Affinity Designer. You export the SVG, pull it into Blender or Bambu Studio, and... nothing. Or rather, a microscopic speck in the center of your workspace that requires 10,000% scaling just to see.
It’s annoying. It feels like the software is gaslighting you. You set your document to 10 inches; why is it appearing as 2 millimeters?
The reality is that "standard" SVG scaling is a bit of a myth. After a lot of trial and error (and more than a few failed prints), I finally found the bottleneck. It isn't your design; it's a legacy math problem hidden in the DPI settings.
The 90 DPI Secret
If you want your SVG to import at a 1:1 scale, you have to change your document setup in Affinity before you export.
Open your Document Setup in Affinity Designer.
Find the DPI field.
Change it to 90.
Why 90? It’s a bit of a tech fossil. Blender’s SVG importer is based on an older standard, likely inherited from early Inkscape versions, which used 90 DPI as the base unit. Most modern design software defaults to 72, 96, or even 300 DPI. When Blender (and subsequently Bambu Studio) sees that file, it does the math based on that 90-unit legacy. If your file is set to 300 DPI, the software gets confused, defaults to a different scale, and leaves you with a miniature version of your work.
Is it different for Metric?
I usually work in inches because that’s what my brain prefers for physical prototyping. I haven't fully stress-tested this for a pure Millimeter workflow yet, but the logic should hold. Since the issue is how the importer interprets "units per inch," the 90 DPI trick acts as the universal translator between the vector math and the 3D space.
Practical Complications to Watch For
While this fixes the scale, it won't fix messy geometry.
Expand your strokes: If you have lines with thickness in Affinity, Blender won't see that thickness. It only sees the path. Expand those strokes to fills before exporting.
Bambu Studio limits: Bambu Studio is great, but its SVG-to-Mesh tool can be finicky with overlapping paths. Clean up your layers in Affinity first to save yourself a headache at the printer.
The "Inches" Factor: If you are working in inches in Affinity, make sure your Blender scene units are also set to Imperial before importing, or be prepared to do some basic math anyway.
It’s a small, slightly irritating hoop to jump through, but it beats manually resizing every single bracket and plate you try to manufacture. Set it to 90, export, and get back to actually building things.