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Super Sampled Rendering and Anti-Aliasing Fine Lines

Applies to:FAFA 3DFA 3D-AV

References: Render to File and Render State Panels
Related Tutorial: Basic Rendering Tutorial
Article: Advanced Rendering - Pausing, Resuming, & Recharging Your Images

What does Super Sampled Rendering Do?

Super sampling is a technique for rendering the image to a buffer that is larger than the desired final image size. At the completion of the render the intermediate image is resampled back down to the desired image size.

Super sampling’s units are a integral multiple of the original image size. Fractal Architect supports 1x, 2x, 3x, and 4x super sample amounts. (Super sampling of 1x turns off the super sampling and is the default.)

The resampling step uses a spatial filter to produce an ideal anti-aliased reduced image. You can choose one of 15 spatial filter shapes and set the spatial filter strength which determines the amount of blurring applied to the larger image before it is reduced in size.

The slight blurring is important step in the image reduction process, as it removes possible image reduction errors and artifacts. In practice, the filter weights are small.

Testing shows that Lanczos3 does the best anti-aliasing of fine lines. Gaussian is another good choice but does add slightly noticeable blurring of fine features.

You should continue to use the legacy Flam4 and Fractal Architect anti-aliasing parameter: Supersample Width. This influences the amount of random jitter noise added to the rendered image which improves the image. (This may be counter intuitive but basically it does the same thing as what Audio engineers do when they master music CD’s by adding small amounts of noise.) Combining Supersampling aliasing along with the Supersample width jitter setting gives you the best anti-aliasing of all.

You will get noticeably better anti-aliasing with the default Supersample Width of 0.35 than by setting Supersample Width to 0.0.

Recommend Filter Weight for the Lanczos 3 Filter Shape

Super Sample Amount Ideal Filter Strength Ideal Supersample Width
1 x 0. 0.35
2 x 1.4 0.35
3 x 1.9 0.6
4 x 2.4 1.0

Supersampling Benefits

Super sampling is a great technique for anti-aliasing and preserving fine image detail like lines. You should be able to achieve great results with a supersample setting of 2x. 3x can be used too, but fine details may disappear or be hard to see.

Even so, most fractals will not benefit from supersampling. Its best to experiment and find the best output image quality for each fractal. If the image has fine lines and significant fine detail, then super sampling is recommended; otherwise it is not recommended.

Supersampling Disadvantages

Super sampling creates much larger intermediate image buffers to render to. The extra memory required grows dramatically with the supersampling amount. (It grows exponentially).

There is a performance penalty too that is not dramatic. It seems to affect GPU render speed more than CPU render speeds.

Super Sample Amount Memory Required Multiplier
1 x 1 x (no change)
2 x 4 x
3 x 9 x
4 x 25 x (huge !!)

Where Do You Set the Supersampling Amount ?

The Triangle editor, Render to File dialog, and the Batch Render to File dialogs all allow you to set these parameters.