My MeshCam trial just expired unfortunately, but I’ve learned a bit more from making simple models and testing.
To simplify the test, I made a 2x2" canvas with just a 1" square at origin. That saves to an .SVG file that is 144x144 pixels with a box that is 72x72. If I import that into Fusion, I get a box that is .75"x.75". But if I tell Fusion to scale the XY plane by 1.33, I get a box that is 1.33" x 1.33".
OH! The problem is Fusion squares the area of the plane in both directions at once. So to get a box that is 1" x 1", I need to scale it by the square root of 1.333, which is ~1.1547, which is what I found empirically. Interesting!
This is the same whether I tell Graphic to scale the SVG file when it is exporting or not, Fusion sees it the same. Loading the file in Inkscape, I get different results. The non-scaled SVG file from Graphic loads as 0.809" (not sure where that comes from) and the scaled up version loads as 1.076" (close, but not that close).
In case this is helpful to others, I’ve uploaded the test files in this same thread on Inventables:
-Mark