Drawing Scale Between Visio and ESTLCAM

I drew a diagram in Visio of the slots I want the CNC to mill into my work surface to mount some t-slot for workholding. I used Visio because I knew how to specify the exact size of the objects. I exported the drawing as an SVG and imported it into ESTLCAM, which asked me what the units of measure were. I said inches, since that was what it was in Visio. When the drawing opened in ESTLCAM, it was 511 inches long (not 30 like it was supposed to be)!

After figuring that out, I imported the SVG again and set the units to mm. This produced a drawing that was about 75% of actual size.

Any tips on how to create an actual-size drawing? I need the precision for milling out the t-slots.

I have Inkscape as well as Visio, if that helps.



Apparently there is a known issue with scaling SVGs that has to do with SVGs being based on pixels rather than units of measure. It’s possible to figure out how much to scale the SVG to get the right actual size, but instead I just exported out of Visio as a DXF file, which had the correct dimensions.

Almost ready to cut my t-slots (don’t worry I’m going to try on some practice boards first!).



SVG is a horrible file format - there are at least 8 different units of measurement - and one of them is “Pixel” which in turn depends on the programs DPI setting.
If you open a SVG file in Estlcam you can select the unit and also the DPI setting.
After this you can use the middle mouse button to measure distances on your screen and check if you got the right one.