Why we need rendering for our design, construction and Animation projects?

computer generated animations showing the exterior of your project including topography and vegetation. These exterior animations allow our clients to more fully understand the proposed design and visualize what their project will look like when it is built. Additional views, including interior stills or animations, can be provided to allow you to better understand the design of your new project. Our visualization do not stop with3D but follow through into stages that include animated scheduling of your project construction. Should you choose our4D animated construction services will coordinate the project schedule with each project element as well as resources of material,labor,and equipment associated with your project. This full service visualization will package your project 

Theoretically, Rendering gives the final appearance to models with visual effects, such as shading, texture mapping, shadows, reflections and motion blurs. Thanks to improved rendering algorithms and hardware acceleration, the software is more powerful than ever. Add to that the fact that high-end engineering workstations are now available at all-time low prices, no one should be left out of the rendering game. The rendering can be a DIY job, but it really depends on the results you want to achieve.

Rendering can improve the waterproofing and fire rating of a building, but the primary reason for doing it is aesthetic. Product visualizations created with rendering software help the product development process in myriad ways. They help “sell” ideas or concepts long before they exist in physical form; communicate important product information to customers, such as instructions on how to assemble or use new products; help engineers identify design problems; and can shorten time to market.

So you can allow people to get what's in your mind especially with people who have limited imagination capabilities. It's a form of presentation as I like to call it.

I agree with the above posts and have nothing to add...

 I agree with  MR  YAQOUB because his answer enough 

We need Rendering to show actual end result for the product. It will give you the realistic result to show clients and satisfy them. 

In film or TV commercial industry everything comes after hi-end rendering and animation. 

To check the orientation of members

most of the time you will use that to show the final product to the client as to  approve material and shape etc 

to explain your work to others in a basic way