Judgement Day - Work in Progress #4 (Patreon)

Shot 3 Full Rendered Preview

SO I've been hard at work creating some really complicated shots for Judgement Day over the past couple of weeks. Shots 3 is completely done while 4 is on the way and should be completed in the next couple of days. I hope you all like what I have to show!

Building Facade Destruction

The most complicated element of working on the third shot was Legacy swiping the facade of the building away with his hand. I ended up using MPM again for this like I did for the stomp effect, but this ended up presenting its own challenges.

One of the essentials of creating proper destruction is making sure your geometry is water-tight without any non-manifold edges. In layman's terms, non-manifold geometry is geometry that CANNOT exist in the real world. Floating (disconnected) geometry, internal faces, edges with more than two connected faces, and areas with no thickness are all considered non-manifold.

This is because because during fracturing, boolean operators are used to cut through geometry. If non-manifold geometry is present, the cutting step typically fails and you get something like what's below.

For this reason, the interior of the rooms are modeled with thickness and aren't just flat planes.

The facade of the building also originally didn't come with back-facing polygons so I had to add them before bringing all of it into Houdini. It's also important to note I am only fracturing/simulating the area of the building that collides with Legacy's hands. This prevents unnecessary computation time.

Moving onto the actual simulation part, the node setup is relatively simplistic as I don't have to worry about multiple materials interacting with each other.

For this MPM sim, I made the decision to split the building into different sections and then source those sections. This was important as it made it easier for Houdini to figure out how to scatter the points within each part of the building.

After simulating, I carried over the same method used before for sourcing into fracturing.

Creating the pyro was essentially the same as how I did it in this WIP. After that, it was a relatively headache inducing export into Blender for final render.

Shot 4 WIP Render

Shot 4 isn't quite done yet, but I at least was able to render out the current state of the shot overnight for you all. I've got a handful of tasks left to complete, but it should hopefully be done within the next couple of days!

Prop RBD Physics

One of the most fun parts of being a Blender artist is that sometimes you find ways around a particularly weak area of Blender. That area, for me at least, is Blender's VERY rudimentary rigid body dynamics system. To accomplish the bouncing furniture and props, I had to think outside of the box.

Normally to create such an effect, you'd have an impulse force enacting upon your physics objects. Unfortunately while Blender CAN do this, it can't produce the wildly random and quick spurt of motion seen above. So... how do we get around this constraint?

Let's just clip geometry into the physics objects and see what happens! I am not kidding, this is exactly what I did. If you've ever seen a rag-doll or physics object in a game glitch out wildly due to clipping, this is the same idea. However, this "clipping" only occurs for a singular frame so that the objects don't continuously look like they're having a seizure.

It's simply just a flat plane that causes this to happen. The more that the plane clips in the geometry, the higher it will fly. I had to move the plane down to where it JUST clips into the furniture so it only tosses the objects a reasonable amount.

And that's all for this WIP! This is what I've been doing for the past couple of weeks, but I'll be ready to begin on the new Aak animation soon. Stay tuned for more!