Here is what I have learned so far...
I drew a 1"x1" box in QCAD using the rectangle function, converted it to a polyline and saved as a R27 (2013) DXF. QCAD units were set to inches
- If you OPEN or IMPORT the DXF into Inkscape and scale by 25.4 using the options tab, it shows up as square of dimension 1.011" as a closed entity that can have a fill applied to it
- You must change the Stroke thickness to something small (.001") for it to show the true dimension of 1"
- If you do not convert to a polyline, it will open/import as a bunch of unconnected lines that cannot be filled until the nodes are connected
I drew a 1"x1" box in QCAD using the rectangle function, converted it to a polyline, exported as an SVG using the advanced export (1" = 1")
- You do not need scale it upon opening or importing into Inkscape, but you do need to change the stroke to something very small (.001") for it to show the true dimension of 1" otherwise it shows a dimension of 1.010".
- If you do not convert to a polyline in QCAD, it will open/import as a GROUP in inkscape, but will still be unconnected lines inside the GROUP and will not be able to be filled until the nodes are connected.
So...
- If you are saving a file from QCAD as a DXF, you will need to scale it by 25.4 while opening in Inkscape
- If you export from QCAD as an SVG (1"=1"), it will import into Inkscape at the proper size
- Both ways need to make sure the objects are closed polylines in QCAD before saving or exporting or they will not work well in Inkscape without connecting all the nodes
- Both ways need to have the stroke in Inkscape set to something very small or it will not show the dimension properly due to the stroke width.
How is that for confusing
Image showing where to set units in QCAD to Inches
Image showing where to set scale while importing DXF in Inkscape
Image showing where to set stroke thickness after opeing/importing DXF/SVG in Inkscape