Baking hell - too many objects

Constant difficulties here. Only solution is to convert as many placeables as possible to environment objects.

The Walkmesh

The 'Baked' toggle button shows you the current state of the terrain bake. Turning it on and off will show the changes that you made.

To make any changes to a walkmesh first turn off the "Baked" toggle. Make your adjustments, then rebake the level before running.