3D Architectural Rendering is the process of depicting unbuilt architecture or interior design into realistic computer-generated images (CGI),
a branch of the architectural design, whose purpose is to show how buildings will look before being build.
Modern architectural renderings fall into two main categories: pre- “design-study,” by which an architect develops the initial concept of a proposed building,
and “presentation rendering,” which is the agreed final design made publication or client presentation.

Everything begins with creating three-dimensional objects (buildings or internal spaces) in 3D software made for the purpose.

Materials, light, texture details, and perspectives are the subsequent steps applied.
When the 3D model is fully complete, it is processed by the software into a 2D image (CGI); the process is known as 3D rendering.
The first 3D rendered image is created in 1976 created by students of the Unversity of Utah (according to Wiki) for science fiction movie Futureworld.