View Full Version : Help with Blender fluids

07-20-2009, 07:18 AM
I am using the Blender's fluid simulation capabilities, which are awesome btw, to animate a pill dropping into a conical flask half full of water. The flask, pill, and volume of water have been modelled in LW and then imported into Blender, where the fluid simulation is implemented. The resulting baked fluid meshes are imported into Layout using the Splotch Blender liquid importer.

Animation-wise, the pill drops into the water okay simulating the splash and ripples. However, the sides of the volume of water are always rough instead of being the nice smooth surface one would expect it to be from contact with the interior of the flask. The attached images, showing just the volume of water, illustrate the problem.

I have experimented with many different settings in Blender's fluid simulation (e.g. upping the bake resolution) to try and eliminate the rough sides of the water, but to no avail.

Has anyone any suggestions as to how to overcome this problem?

Thanks in advance,

07-21-2009, 05:05 AM
That's very odd, it almost looks like the SPH particle volume is being adjusted for gravity, but not for the collision with the container. Are the "rough sides" of the volume shown actually projecting into the volume of the fluid container (e.g. do the two volumes now intersect)? Or is the fluid volume disjoint from the volume of the container itself?

Also, is the bottom of the fluid volume rough or smooth?

[edit]Is the container represented in the fluid simulation, or did you just limit the domain of the simulation such that it can't go beyond the volume of the "interior" of the container?

BTW, you might want to attach the blender simulation files to the thread, if not too ridiculously huge, so that folks can look at how you set it up.

07-21-2009, 07:22 AM
Hi John,

Many thanks for taking the time to reply to my plea for help.

The top and bottom surfaces of the Blender fluid mesh are smooth - it's only the sides that are rough!

All the LW objects imported into Blender are completely contained with in a cubic fluid domain object (I seem to recall that the shape of the domain object is not important for the baking process - it only needs to be sized to just enclose all the objects in the fluid simulation).

The fluid volume in the LW model fits within the walls of the flask with a small gap between the two surfaces. Note, I have also tried it with no gap between the surfaces. However, in both instances the resulting Blender fluid mesh has rough sides.

Attached is a zip file containing the LW and Blender project files.


07-21-2009, 01:47 PM

surface subdive -> 0

surface smoothing -> 3-4


07-21-2009, 02:05 PM
Hi nudel,

That is a mega-improvement - many thanks! :thumbsup:

Also, thanks to everyone else, such as John, who've spent time looking at this problem.