Antialiasing, Sampling, and Filtering Tips & Tricks

Here are a few tips & tricks to help you set antialiasing, sampling, and filtering options correctly.

• Avoid adding antialiasing when you render a texture map that fills up the screen because its edges aren't visible anyway. If the texture map itself is already antialiased, you don't need to add more antialiasing when you render.

• Before adding antialiasing to improve the quality of motion blur, try fine-tuning the motion samples value instead.

  Motion samples can increase the quality of your motion blur without substantially affecting render performance, and usually without adjusting the antialiasing settings. For more information, see mental ray Rendering Settings [Cameras and Motion Blur].

• The minimum and maximum sampling values should never be set to identical positive values, as this defeats the purpose of adaptive sampling.

  Too much sampling is done in areas that don't need it, which slows down rendering.

  Identical negative values, on the other hand, are useful for rough previewing since they limit the number of samples and speed things up. For example, rendering with values of -1/-1 is faster than with settings of -1/0.

• Before raising the sampling value, try lowering the sampling contrast values.

  This can increase the quality of the rendered image with less of an impact on rendering performance.

• Using sampling contrast values of less than 0.05 can lead to unnecessary oversampling and slow down rendering.

• Use triangle filtering when you need to preserve image sharpness.

• Use Mitchell or Lanczos filtering for a final render.

  This will increase rendering time, but the quality of antialiasing will be much higher.

• Turn on jitter for images with a slow transition between colors. This will increase rendering time.

  You can also turn on dithering to prevent banding.

• Sometimes, changes to the sampling pattern from frame to frame can cause flickering in a rendered sequence. You can reduce this flickering by activating the Framebuffer Sample Filtering Use Same Sampling Pattern for All Frames option.