Soft ambient occlusion doesn’t work that well for car underbodies, we need something directionally biased (bent normals? contact shadows?) and way rougher:
Now combine that extra-strong AO with shiny plastics and metals:
We are starting to get somewhere! The “glass” material doesn’t exist, so I should bust those windows out for now. There won’t be any transparent materials (glass) until I dump the strictly deferred architecture for a forward+ or some hybrid two-stage renderer.