Hi Vladimir, sorry I didn't know it was the direction of the arcs and circles in the DXF that you were referring to about the bug. I've seen some programs miscalculate the actual geometry for arcs in cases where they have a plane normal pointing downwards in Z, I thought that might be what you were seeing.

It does look like MoI is not preserving the arc direction for its DXF output, I'll see about tuning that up.

Thanks for reporting the bug!

- Michael