Week Four (Final Project)
- gracieszymanski04
- May 26
- 4 min read
Updated: May 28
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Finished 428 Project:
Responsible for all aspects except modeling.
References/Inspiration
Image One: Creature for the Harry Potter Movie Franchise
Image Two: Work by artist Min Song: www.minjsong.com
Image Three: Aesthetic reference image from Pinterest: https://www.pinterest.com/pin/1829656094507874
Resources/tutorials used:
Overall Breakdown:
For this scene, I used multiple simulations for both the body and figure of the magical cat, as well as some simulations for the creation of the environment of the cat.
Main body simulation:
The body particles of the cat were done using a pop net that utilizes noise networks inside of vop nets to make the particles move in a curly and swirly way. The particles are affected by two main noises. First, I created a noise using a VDB volume and used a volume vop node to give the volume noise. I used the node called "curl noise" inside the vop and played with frequency to get the noise to my liking.
This noise is used inside the pop net for the particles to use as their velocity so that they move in this same curl noise.
The other noise used was a noise created on the mesh of the cat. This was created using a vop net that multiplied together a "vein noise" and a "flow noise". Both of these noises were also animated. The effect created on the mesh of the cat was used as the cat's density and then used to spawn particles. Therefore, the particles of the simulation spawn from the white parts of the vein noise as seen in the image.
Besides these manipulations, there is also a vop net to force the particles to stay stuck to the surface of the mesh, as well as a pop wind that is used to create a dynamic exit for the cat. The pop wind is keyframes to only activate and affect the cat's particles after a certain frame.
To make the enter of the cat more dynamic, I used a simple boolean on the mesh that the particles spawn from so that the cat would appear from the feet up out of thin air.
Smoke simulation:
For the smoke simulation that surrounds the cat, the pyro solver was very straight forward. Two of the biggest changes I made was to the dissipation and the turbulence of the smoke. I upped the dissipation so that the smoke would fade quickly and upped the turbulence so that it would appear more wispy.
Again for this simulation, I also used a noise on the mesh of the cat. For this noise, inside the vop net is a "flow noise" node that created a pattern on the cat that I then used as the density. This way, the smoke spawned in a more sporadic way, rather than simply using a pyro source spread that would have evenly spread smoke along the body of the cat.
Sparkle simulations:
For the sparkles that drift across the cat's body and fly off, there are two pop nets that create these. There is one for the particles that simply emit off of the cat mesh and fly up into the air and one for the particles that trail the body of the mesh and then fly off.
These are relatively simple pop nets with the biggest factors being their wind and the pop speed limit nodes. I slowed the particles down quite a bit to get them to appear more peaceful rather than rapidly flying all around.
The floaty particles that come from the floaty pop net are rendered out as simple sphere with varying size. The particles from the flowing stars pop net are rendered as little stars of varying size.
Environment Building
For the water that the cat is magically walking on, I found the ripple solver in Houdini 20.5 that takes any mesh and gives is ripples that are created from collision points. For this, I used a grid as the water and connected that to the ripple solver. For the collision objects that would actually create the ripples, I used the animated cat mesh as well as a pop net that created random little droplet ripples that are often scene in more serene environments and backgrounds.
For the environment sparkles, I used two layers of pop nets to create the floating sparkles. Again, both were very simple with just a bit of anti gravity, some wind for movement, and pop speed limits to slow the particles down for a serene setting.
Compositing
For this project, I rendered out multiples layers of the cat in order to composite them separately and use some masks in compositing so that I could have more control over how the magical cat looked. This included rendering out particles in separate layers, as well are rendering out ambient occlusion and fresnel passes of the cat mesh.
Here is how these layers were composited together using masks, grades, and glows to create the finished product:
5/28/2025
I was able to receive professor feedback yesterday about my project and she suggested changing the speed of the cat blowing away. Therefore today, I spent some time changing the wind to be slower and longer. It now starts at from 140 instead of frame 160 to give it more time.
Before Timing:
After Timing:
5/27/2025
Today, I was able to get all of my renders done and also added a new layer. In substance, I used the cat model to add a gradient swirl pattern to a shader. I also added a little star decal on the forehead of the model. I then took this texture into Houdini and rendered out a render layer pass with this texture to use in compositing.
I took this render pass and other render passes into nuke and did some compositing work to get my final result. Here's my current final animation:
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