>>198478722.5D means the illusion of 3D while using tricks in a 2D renderer. I agree that it can seem like splitting hairs at times but there is a distinction.
For me, the use of 3D models (meaning the model itself can be placed and rotated in 3D space freely) is the distinction. Taking a 3D model and generating X number of perspective views for it as 2D sprites is no longer 3D rendering.
If you are just rendering per-pixel or per-quad using "painter's algorithm" of y-occlusion or ray-tracing then this isn't really 3D.
Would isometric style 2D games be considered 3D because of the appearance of multiple dimensions? The rendering engine is still 2D + height which may sound like 3D but you are limited in what/how you can representing that compared to full 3D space.
For example, let's take Rollercoaster Tycoon. Is this 3D or 2D? It has depth and height, but you cannot freely move the camera around because it is not truly 3D rendered. Compared to something like Ragnarok Online which the world was 3D and the sprites were just 2D, it was still 3D.
