Rendering is the process of adding texture and tone to an image to create a 3D effect.


In computer graphics a render is generated form a scene file, which contains vital information to the image, such as lighting, texture, viewpoint, and geometry. The final image is output to a digital or a raster graphics image file or animation which can be viewed as a pre-rendered image or movie.

Computer games render in real time during game play. Since rendering places quite a load on the system, there is a limit on the detail (quality) of games graphics that can be rendered quickly enough for comfortable game play. Cut scenes are pre-rendered, which explains why the graphics are usually much better for those.

Render Engines

The software that generates a render is called a render engine. Programs like Autodesk 3DS Max generally have a built in render engine. Other render engines can be added to the modelling software as plug-ins. These third party render engines are used because they offer features or better quality rendering than the 'native' renderer.

Two common render engines used with Autodesk software are Mental Ray, which is provided with 3DS Max, and Vray, which provides high quality professional renders.

Managing the render process

The render process places significant demands on a computer system, and a detailed scene may take a long time (even hours) to complete, particularly if it an animation and a series of frames need to be rendered. As a result it is necessary to be able to manage the rendering process so that a designer can go on with their work while they wait.

Assigning render to a server

A render operation can be assigned to another computer (render server). In the case of an animation a collection of render servers might be assembled into a "render farm". The frames are shared around the computers in the farm to speed up the render process. Using these processes speeds up rendering and allows a designer to go on with other tasks while the rendering is taking place. In Autodesk 3DS Max a package called Backburner is used for this.

Speeding up the process

There are a number of ways to speed up rendering:

  • The first way is to change the configuration of the computer system you are using to use resources more efficiently.
  • Ensure that unnecessary things have been removed from the scene.
  • If the render is just to see how the work is progressing (test render) then focus the render on the thing that is being checked. Hide or remove parts of the scene which are not needed for that render. Remove shadows, caustics, lights etc. as these all add to the render time.
  • Render at a reduced resolution until the final production render.

So broadly speaking the render process can be speeded up by adjusting the configuration of the computer, by simplifying the scene or focussing on the parts that need to be rendered or by changing the configuration of the render engine to produce a poorer quality (draft) render.

You will find a good summary of these techniques at

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