How to bake hi-res into to low-res model with a multires modifier?

I have a hi-res model with terrible topology, and I want to create a low-poly model with good topology which uses a multires modifier to capture all of the detail on the high res version. This is not a sculpt - the hi-res model is of a car imported from another program. Once I add the multires to my low poly mesh, is there a way to bake the height info from the high poly mesh?

Sure! Add a shrinkwrap mod after the multires… it wants to shrinkwrap to the high-res car. Then you can apply the shrinkwrap and the hieght data will be sucked into the multires mod.

I’ve tried doing that, but the car has a lot of flat areas with sharp seams. Once I start increasing the resolution of the subdivision surface, it starts to look pretty bad. The car also has a lot of gaps in it - the seams don’t connect so it’s essentially a couple of dozen curved planes floating in space with tiny gaps between them.