I just bought a new filter for my shop vac and after one session with the planer it was caked in dust and chips.  Tired of cleaning this out, I decided I would make a chip separator to keep the bulk of the material away from the VAC.

The 3d Printable parts and instructions are located over at Thingiverse.

Left Hose – Intake
Right Hose – to Shop Vac

Catches the bulk of the sawdust and chips.

After filling up the separator, just a little dust in the bottom of the Shop Vac and the filter was clean.