First of all I now let the surface kernel be different from the SPH kernel. The SPH kernel has a lot of math that it must obey in order to work properly which a "viewing" kernel does not need. The result is a much nicer looking surface, but far from perfect. There is a catch, you need to set the isosurface threshold down to 1 rather than the default 500. Otherwise you won't see a thing. My current viewing kernel is (1-r^2)^2 and is often used with metaballs. The results is much better and just results in a small amount of roughness. With some adjustment even better results are possible.
Here is an example:
With a larger threshold:
Both in a composite:
Same but with polygons Ray traced:
Ray Traced Poly Surface
lower threshold and higher poly res. Note that rendering time is dominated by the mesh build. So this could be much faster for transparent fluids.
Ray traced with finer polys and larger threshold
And a composite:
The Above together in white this time
As you can see the threshold can make some difference. Generally there is no right value and it will need to be adjusted. It should be noted that other fluid packages has similar parameters that need to be adjusted. Surface tracking is not a exact problem and hence the different methods that are used to tackle the problem. Also this will make less difference with very small particle sizes. But it will be slower.
The final version will be almost be 100% based on a mesh. But a good mesh is very slow to build and hence may need to be backed in with the rest of the simulation. In real flow you can bake lots of mesh's to a single "particle" bake and you can then adjust the different parameters better for different views (aka close ups vers far shots...).
The trick with meshes is not that they are better, in fact they will be the same as the isosurface examples above. But note that these examples are only a little rough and some smoothing could make it almost perfect. And that what we do. We add post smoothing to the mesh, usually via a iterative scheme that can be tuned.
Unfortunately the mesh code has some issues. First is the fact that there are bugs. For some reason when the mesh preview is on the cpu goes to 100% and never stops. Has anyone else noticed this? The next is that there are some cases that i get null triangles. And the biggest is that is uses some code that nobody seems to have written. This creates clear issues with the GPL'ness of the code base and I may just have to rewrite it.
I will still keep the isosurface code and at this point it gives the best results. You get some performance issues however and the best way to deal with that is to turn on the useSampleGrid option. In my scene above they caused the render to be about 5-10 times faster, and the difference would be even greater with transparent fluids.
Other changes are there are now some options for fluid objects. The first is a dither and just randomizes the particle positions so as to loose perfect alignment effects. The other is x, y and z ratios. These are fill ratios in these respective directions. The default gravity is in the y direction so if we set y to 0.5 the object will be half full. Also the fluid objects and softbody objects no longer get "blobs" at the vertices's.
Add one more render:
The updated plugin is at the same link as last time. The last post still makes up some of the release notes.
Do not forget to change the threshold to about 1 or a little more for this version.