2.5 times yuan refers to some height gauge software can achieve 3-dimensional measurement, but the measurement needs to rotate the workpiece, not as convenient as the three yuan, the manufacturers call themselves 2.5 times yuan
Three yuan refers to the three coordinate measuring machine, an industrial measuring equipment, used for the shape and positional tolerances of the parts products measuring instruments.
Four times the yuan in the field of industrial measurement there is no such thing.
The above is the real world version of something.
The sci-fi version is as follows:
The second dimension is the flat world, including anime and manga, of course. In the last few years it seems like it's starting to scratch the peripheral world into it as well. For example, COSPLAY moe, voice actor's voice, handmade items and so on, all related to the two-dimensional world of anime, are classified as the secondary world
2.5-dimensional of course, is the existence of between the world of anime and the real world. The circle that exists in the peripheral worlds, products that exist between anime and reality, like the one mentioned above, is known as the 2.5 subgenre, though the term 2.5 is slowly disappearing now that the classification is becoming clearer.
Third dimension refers to the real world.
The "fourth dimension" is the addition of a timeline to the original three-dimensional axis