Rendering is the making of the final still image or animation - it can be very professional-looking and realistic, with shadows, reflections, textures and transparency like this render of Suzanne, Blender's mascot.
Blender does not render continuously since rendering involves a large number of calculations. This is especially true of animations. A 10 second animation, for example, with 25 frames per second (still images per second) would contain 250 images, and each frame might take several seconds to compute, so the rendering of such an animation might take several minutes. Rendering a full-length movie might keep a powerful computer busy all night! Once the animation is done, however, it should run very smoothly - 25 frames per second is same as the frame rate used by European televisions.
To control the rendering process, click the render button in the properties window. Here are the most important settings:
Rendering a still image
Clicking the 'Image' button or pressing F12 or choosing Render>Render Image renders a still image of whatever the active camera sees. By default this will display in full screen but it is better to choose the 'new window' option for two reasons. Firstly the rendering process in version 2.5 alpha 2 is a bit unreliable and is more likely to crash Blender in full screen mode than in a new window. Secondly when the render is done full screen you may well click the red close box to dismiss the render, not realising that this will cause Blender to close completely and without warning you to save your work. The correct way to dismiss the render is to press F11, but will you remember this? If the render is done in a new window then you can close the new window by pressing the red close box - no problemo.
The size of the rendered image is set by adjusting the X and Y values (1920 x 1080 is the resolution of HD video). If you are not yet ready to do your final, finished render and just want a small, quick low-quality render then set the percentage to less than 100%.
Rendering a still image does not save it to your hard disk. To save the rendered image to your hard disk choose Image > Save As in the render window then specify a file type in the 'Save as' section (bottom right) choose a location, give a file name (if you don't include the extension it will be added automatically) then press the 'Save As' button. It is also possible to specify the desired file type before you do the render by setting in the Output section of the Render panel of the Properties window:
Rendering an animation
Clicking the 'Animation' button or pressing Ctrl+F12 or choosing Render>Render Animation will cause an animation to be rendered - this can take many seconds, minutes or hours according to how long the animation will last and how big it is.
As previously mentioned, the dimensions of the animation can be set in the render panel and it is possible to render at a percentage of less than 100% if you want a quick, lower quality render because you are not yet ready to make the final high quality version. Before doing the rendering, be sure to set the Output file format to a movie format and not to a still image format such as PNG which is shown in this image and which is probably the default. A good choice would be AVI JPEG since this is a compressed format that should be playable in standard players such as Windows Media Player. If you leave the file format as PNG then you will get hundreds of individual files rather than a single movie file. Note that animation renders ARE saved to your hard disk, unlike renders of still images, so be sure to set the folder name (/tmp\ by default) to a folder you have access to. If you leave the default folder as '/tmp\' then Blender will save to a folder called 'tmp' on your C drive (it will create this folder if it does not exist). You do not have access to the C drive at school so be sure to set the folder to h:\ instead - this is your personal folder.
When the render terminates (after several minutes, probably) you should find that a movie file has been created in your chosen folder. Double-clicking this file should open it in the associated player.