I have an emitter set to emit objects. The source object itself belong to the rigid body world. Yet the emitted versions of the object fall straight through the floor even though the source object hits the floor as it should. Have I missed a setting or is this just how it is? Would I need to alt-D the object many times and drop those, so as to not need and emitter? Thanks.
Not really. Particles can display newtonian physics, but it only applies to their origin points not their surfaces, so meshes will intersect. You would have to use the particle system to generate the instances, but then convert the particle system to real objects and make those into rigid bodies.