You have several settings for what POV-Ray does while it renders. On Mac OS X, you can find the settings for your scene under the “Edit” menu. There are three important sections to the settings: the Scene, Quality, and Output panes.
In the Scene pane, you’ll almost always want to have Show Preview checked. For scenes that take a long time to render, you might find Mosaic Display useful while testing the image. This renders the image in progressively smaller chunks, making it sort of “fade in” as it renders. This allows you to see potential mistakes without having to wait for the entire scene to render. Some complex scenes can take hours! None of the ones we’ll be working with here should take more than a few minutes, however.
The Quality pane lets you specify the quality of your final image. If you reduce the quality, the render takes less time. Usually you will want to leave Render Quality at the maximum. When you reduce the quality you are actually removing information from the final image. Depending on the render quality, you may lose shadows, reflections, and even textures. A reduced-quality image often will not show you what you need to see to know whether your scene description is correct.
Anti-Aliasing smooths out the edges of your objects. More specifically, it smooths out the edges of any adjacent colors. Anti-aliasing almost always makes the resulting image look nicer. It makes the render take more time, however, so I will often leave anti-aliasing off until I’m finished. I’ll do the final render with anti-aliasing turned on.
Here’s a close-up of our blue sphere, with anti-aliasing turned off and anti-aliasing turned on. Notice the “staircase” effect on upper part of the left image.
The more sharp transitions from one color to another, the more you’ll need anti-aliasing for your final render. Anti-aliasing and mosaic preview do not work well together, so when you do your final, anti-aliased render you’ll want to turn mosaic preview off.
In the Output pane, you’ll set the size of the image, the kind of the image, and whether or not to add an alpha channel. I’ve been rendering this image at 640 by 480.
I prefer to save my rendered images as PNG, because it is a fairly universal format. From PNG, I can use image software such as GraphicConverter, GIMP, or Photoshop to convert the image to JPEG, GIF, or compressed PNG as needed. But I keep the original POV-Ray PNG so that I don’t have to re-render to get a higher quality image.
The alpha channel is very useful for creating web images and for merging POV-Ray images into photographs. Turning on the alpha channel makes the image transparent where nothing exists. In our current image, there is only one object, the sphere. If we turned the alpha channel on, every other part of the image would be transparent. This makes the image useful as, say, a button or icon on a web page. If your page is white and you put the blue sphere there, it will appear as a blue sphere on a white background: the black is transparent because nothing is there. The alpha channel is especially useful for anti-aliased images. In an anti-aliased image, the smoothed sections will have varying degrees of transparency, removing the halo effect you often see when trying to match smoothed images to a web page’s background color.
