Fluid simulation project

During the past few days, I re-wrote my fluid simulation project.

I modulized everything in a way similar to the fluid simulation pipeline in DreamWorks. Also I modified the mesh extraction part to make it much more faster.

The performance right now is 15~20 seconds per frame using single core CPU for 150K particles. I didn't use the optimized algorithm for single core because I'm planning to doing everything in parallel on CPU. So in terms of performance, this is the worst case. However, to my satisfaction this is still pretty quick.

Here is my new demo reel, including a clip for fluid simulation using 125K particles.

Yet this is not a good demo, because:
1. I'm using a too small smoothing radius for the particles, and ends up with really bumpy surface, which should not be the case.
2. SPH method suffers from severe compressible problem. That would lead to an additional layer in in the surface extraction part.
3. Initialization part was kind of wacky. I've done another simulation using the sample method for initializing particles from the Ghost SPH paper I've been working on. And the result is better.


For the 1st and the 3rd problem, I've already improved my project to solve these problem. The openGL version images are already there, and I'm planning to render out a maya version for a better demo.

However, because of the compressibility, the second problem could not be easily solve. I've tried to use WCSPH, yet still I can not find a proper configuration for that implementation, and also I don't think that is a good way to solve the problem. It's just a numerical method dedicated for this problem, but not physically based. My original plan is to implement the Ghost SPH as a complimentary part of my simulator, yet that paper suffers from lacking of elaboration, and even by contacting the author I still did not get a satisfying answer. Now I've started to wonder how they implement that paper.

The good news is, I'm planning to turn to FLIP for the solver part. FLIP combine the best part of eulerian method and lagrangian method, and I believe that would be the best solution for me. Hopefully that won't be too hard.

Another item on the to-do-list is to substitute marching cube with dual contour method.

BTW I might implement another version using PCISPH combine WCSPH for comparison. My personal expectation for the FLIP method is to be better than PCISPH + WCSPH.

In the end, I'm still obsessed with ghost SPH. If anyone want to discuss about that with me, I'll be love to talk about that.

I've been working on this project for a relative long time, and tried lots of things. like the creating level set field for ellipsoids(which is extremely time consuming), and converting obj file to level set. these would be done after I finished the compressibility problem. In addition, my tracer project has to be postponed, cause this project has the most priority to me.