This week I focused on destruction buildings and smoke sim.
I gathered a procedual building HDA writen by some Houdini artist, which is quite handy for generating destruction buildings. By using this tool, I quickly built up a building that I want.
The next step is to fracture the building and turn it into a destruction ready building. I used RBD fracture and voronoi fracture to break all parts of the building and then cached the file to the disk. It took quite a long time to finish since the building has both interior and outside walls.
After that I added constraints to each part of the building so that it can be connected together when the sim started. All the constraints are glue constraints, which can be destoried after the collision object hit the building. I set about 20 constraints to connect the piece and exported them to the disk. Each constraint has be colored by using dofferent colors.
After the building has been set up, I started to test the collision. I find a suitable spaceship model on website and transfered it to VDB for collision. I used some nodes to limit the speed of fractures. After several times of tweaking, I finally got the result that I want.
After that I added debris on the fractured piece. I used velocity and volume as masks to prevent small pieces and low speed piece from emiting partcles. After that I used a pop sim to emit secondary particles from the original particles so that the volume source can get enough particles to form a trail, and then be generated into volume.
I generated flame, density, temperature and velocity source to simulate the smoke and fire. Several micro-solver have been applied to break the shapes of the smoke. The simulation still has some problem since I am not quite familiar with high speed volume sim. Some part of the smoke disconnected because of the high velocity and low substeps. I realized that I need to do more research on this kind of simulation to make the result looks better.
I tried to render out this sequence by using redshift. Unfortunately, my computer is not good enough to run the render in this scene because the cache is too big to be imported into render engine. When I click the render bottom, the screen just freezed. Therefore, I have to export a playblast to demonstrate the result.