I searched online and found several materials, but none of them illustrated this concept clearly, at least for me. For example, the w3schools says it defines how many pixels a 3D element is placed from the view. It's so abstract to totally understand. Can someone tell me in a more vivid easy-to-understand way? It couldn't be better if there are some images to show this concept.
In 3D transformations, perspective gives the object a 3D point of view and attempts to render the perspective of the 3D object from a particular viewer's perspective. It is not easy to understand.
Here's a Safari reference on it.
A beginning tutorial on it.
Some examples of using perspective.
FYI, in the future I'd suggest disregarding all Google search hits that come from w3schools. They have somehow managed to co-opt a high Google searching ranking with incredibly shallow content.
When working in a 3D space, we need to set a perspective value, otherwise animated elements will look flat. How? The perspective CSS property gives an element a 3D space by affecting the distance between the Z index and the user.Remember: the Perspective property shouldn’t be applied to the element that will be animated (through a CSS Transition, Transformation or Animation), but to a parent element.