This week I started to make VFX shots.
There are several shots that requires VFX:
- two blood shots
- one explosion & RBD shot
The first VFX shot is a blood liquid shot. I want the blood to slide on the surface of the printer, and the blood should be quite thin. Therefore, I generated a thin geometry and transfer it to points as the fluid source. I also turn on stick on collision tab to mimic sliding effect. I added some thin blood strings to make the whole liquid more detailed.
The second one is also a blood liquid shot. The blood needs to flow on the carpet and wet papers. I firstly used flip fluid to do the simulation. The flow looks good, but the generated liquid is too thick. The reason why the liquid is too thick is because the resolution of volume in simulation is not high enough. However, high resolution of volume will bring more simulation time and hardware pressure, which can be another problem. Therefore, I turned to use particles to mimic fluid simulation. I added particle fluid node into pop simulation so that forces between particles will be created. To make the cache file smaller, I used toNDC function to group the particles outside of camera and delete them. By adding masked smooth and meshing techniques, the final result looks fine. After that I use sop solver and attribute transfer to make the wet maps on carpet and paper, and later generate them as material masks. By using the wet map, carpet and paper can change materials when the blood flow over them. They will become darker and redish.
Next week I will finish the last VFX shot.