Zach Jantz

FX Artist

Procedural Shells Project

Project

For this project I took the opportunity to create some rendered visualizations of a vex and vops experiment. I focused on creating art directable, product visualization style effects using pyro and particle simulations. The shells were created using vex and based on the paper “Modeling seashells” by Deborah R. Fowler, Hans Meinhardt, and Przemyslaw Prusinkiewicz published at SIGGRAPH 1992. Shots were lit and rendered in Houdini using Arnold.

Shot 1 Breakdown

Vellum grains prep
Simulate the settling grains
Optimize the scene grains
Ground sand grains
The sand on the ground in the shot is created with a vellum grains simulation to settle and disperse the sand on the ground. Using a pop collision detect to stop particles on contact with the collision surface and disabling bouncing decreased simulation time and led to better grain settling.
Create particle guides
Pop sim
Particle re-time
Particles Rising
The rising particles are created by using a pop curve force that attracts particles emitted from the ground geometry. I then re-timed the particle system primitives with a random offset for post sim control.

Shot 2 Breakdown

Source particle setup
Source particle pop
Source particles
I used a pop simulation to create an interesting source motion for the pyro.
Pyro setup
Pyro simulation
Pyro volume
After scaling the source particles by a ramped age control, and applying density I created a pyro sim for the visualization. I decreased the time step and velocity in order to create a more fluid sim. I control the turbulence and disturbance with the density field, using a gas reduce to find the max density.