Hidden lines not showing when I export a dwg

When i export skp into dwg
Hidden lines not showing.

Unfortunately I believe that is a SketchUp specific effect and those lines aren’t rendered in vector and therefore can’t be presented in vector

Those aren’t hidden lines. They are ‘Back Edges’, toggled on/off by key [k] by default.

You could try exporting in ‘X-ray’ or in ‘Wire Frame’ mode.