PML - Filters

Filters are a very important and effective tool to sharpen meshes and eliminate the rounded and “blobby” look. Especially meshes from emitters with smaller particle amounts can profit from this option, but also high-resolution simulations will look better with at least some filtering. Though you might lose details, the result is convincing and actually filtering should be applied to any mesh.

Filter

You can choose whether you want to apply the filters (“Yes”) or not (“No”). Filtering is a very fast method and does not increase meshing time too much. The result is always worth the slightly longer creation process.

@ Relaxation

This type stretches and sharpens the mesh’s edges and gives you a much more natural look. The result is a more watery and realistic appearance. “@ Relaxation” helps you to get quality meshes even from low resolution emitters. The default value is a very good starting point and it is very likely that you will not have to alter it at all. “@ Relaxation” is very sensitive, so instead of changing the filter’s strength it is often better to lower or raise "@ Steps". Though “@ Relaxation” is very effective, it has limits: emitters with just a few hundred or thousand particles are not really suited to create a perfect mesh – even with filtering.

“@ Relaxation” should also be used with care in terms of creating a believable fluid. An overdone effect can lead to very sharp and unnatural edges, and the entire mesh starts shrinking. The higher the settings, the more details get lost. Of course, this is sometimes wanted – for example for a liquid metal look one would expect from mercury or similar substances with high surface tension. Also sponge-like tissues are a very nice field of application for high “@ Steps” settings and the “@ Relaxation” filter. Higher “@ Relaxation” values should be compensated with lower “@ Steps” settings.

@ Tension

If you can see unwanted high frequency structures on your mesh, then it is a good idea to activate this filter type. “@ Tension” flattens the mesh surface and removes these artefacts. Similar to “@ Relaxation”, this type is also very sensitive and strongly depends on the according “@ Steps” settings. Normally, high-frequency patterns do not occur very often, so the “@ Tension” filter is rarely used. Higher “@ Tension” values should be compensated with lower “@ Steps” settings.

@ Steps

Each filter is affected by this parameter. Higher settings strengthen the influence of “@ Relaxation” and “@ Tension”, and they can lead to completely over-filtered meshes. Values above approximately 120 may produce unrealistic results, unless you really want to achieve a certain effect. Another issue is that very high settings will reduce the amount of details. The default value of 64 is sufficient for many scenes, but of course it makes sense to experiment with lower or higher settings. A range between 32 and 96 seems to work best for most applications. Higher “@ Relaxation” and “@ Tension” values should be compensated with lower “@ Steps” settings.