Surface count DEFINITELY affects speed. Take my word for it... I've been using Blitz 3D since it came out.
Each surface causes a stall on the 3D card, and so a realtively few number of surfaces will really bog your framerate down. I don't know more than that, and you don't need to either to make use of the knowledge that less surfaces = better. :-)
Just try creating 400 single surface particles, and you'll see your framerate drop significantly. A single surface system can handle that many easily. Of course, you can't do as much with a single surface system.
One more thing... combnging meshes into single surfaces is a balancing act. When you have a single mesh that whole mesh gets transformed and rendered when any part of it is in view. And you can't hide part of it when it is more distant. And stuff like my shaodw system for instance needs meshes to be small so that their bounding spheres don't intersect the shadow volumes, or else their polygons have to be clipped.
So combine your meshes, but don't go overboard and keep in mind that stuff. There's no good reason to combine every building in a level into one mesh, unless you know that you need to render the whole city at once from high above, and you have lots and lots of buildings visible at once, for example.
Each surface causes a stall on the 3D card, and so a realtively few number of surfaces will really bog your framerate down. I don't know more than that, and you don't need to either to make use of the knowledge that less surfaces = better. :-)
Just try creating 400 single surface particles, and you'll see your framerate drop significantly. A single surface system can handle that many easily. Of course, you can't do as much with a single surface system.
One more thing... combnging meshes into single surfaces is a balancing act. When you have a single mesh that whole mesh gets transformed and rendered when any part of it is in view. And you can't hide part of it when it is more distant. And stuff like my shaodw system for instance needs meshes to be small so that their bounding spheres don't intersect the shadow volumes, or else their polygons have to be clipped.
So combine your meshes, but don't go overboard and keep in mind that stuff. There's no good reason to combine every building in a level into one mesh, unless you know that you need to render the whole city at once from high above, and you have lots and lots of buildings visible at once, for example.