Houdini Vellum Simulation - Goblin Sandbag K.O.

JANUARY 2022

We've recently started a new course and currently studying the different types of simulation which exist within Houdini. Week 1 has seen us dive into the world of VELLUM. We had a total of 3.5 days to create, render, and present a vellum simulation of our choice. In this case, I chose to try and learn some new skills by importing an animation into Houdini and incorporating it into the simulation. The core concept of the simulation was to create a vellum cloth, fill it with vellum grains, and then tear the bags through impact.

I made a total of two simulation versions, one with a Particle Size of 0.01 for the grains and the other, higher resolution sim, with a Particle Size grain of 0.005. My personal favourite was the lower res, 0.01, sim as the first sand bag tore and stuck to the ears of the character, with the second sandbag holding together more before impact, which made it feel havier and more of a meaty connection for a true KO.

Overall, I'm pretty happy with how this turned it out. It's fun to try different grain weights, randomise the seed of the tear lines on the bags, and adjust the height of the falling sandbag to see what different sim results you can achieve.

As always, weekly deadlines ensure that our time was limited but I'm pretty pleased with the outcome and learnt a new skill whilst I was at it. My rendering and composition skills still require some work but I look forward to trying to develop these as the course unfolds. My next sim will be an RBD sim, set to be composed entirely of Lego, and I hope to progress more with my Houdini rendering and sim knowledge as a result.

Both the character and animation were sourced from Mixamo. The character is called "Doozy" and the animation is, as you may guess, is called "situps". Visit mixamo.com and see what works for you...