[ODE] Difference in efficiency between single trimesh geom and multiple trimesh geoms?

[Megan Fox]

Has anyone done any testing on this, where they started with a world
full of one trimesh geom per "world chunk entity" (a flight of stairs,
a door, a piece of wall, a table, etc), then later moved to a
representation where everything was merged into a single trimesh geom?

As it stands, each chunk in my world is defined via solid geoms, with
said geoms associated with the proper entity - "wall", "wall corner",
"floor", "stairs", etc.  Moving to trimesh representation of
everything (in prep for terrain), I imagine I'll keep it the same,
with one trimesh geom per.  I'm just curious how much of a speed
increase I'm likely to see in moving from this to a single-geom
representation of the world, said figure serving as a motivator for
changing things in that direction.

-Megan Fox