PLEASE HELP! Geometry solid body problem when creating external flow volume

pls help with the faults. i think most of it is coming from the tires, but ive no idea what to do

The geometry is already 100% watertight?? What else do I need to do?
This doesn’t make any sense it’s literally one solid object (apart from the rear wing and drive shafts and tires).

I’ve also tried converting to solid in freeCAD but it still didn’t work, this is not intuitive at all.

i tried using the wrap method to create a simulation-ready object but it keeps CLOSING OFF the tunnel inside the car. Everything else works fine. Why does it close off the tunnel??? I’ve already tried selecting “allow tunnel”.

Perhaps, try to import your model in a different file format. STL files are not recommended (unless for LBM or PWC simulations). STL files contain only faceted data and are thus difficult to convert to a solid body.

What other formats do u recommend? step. file doesnt work either I’ve tried. It’s frustrating because I know 100% that it is a watertight geometry (checked in both in Blender and freeCAD).

The suggestion would be to try STEP or Parasolid.

Ive figured it out. I used freeCAD to convert to step.