Fun with VFX

After watching a visual effect shot in Prince of Persia: Sands of time, shared by my groupmate, Ayesha, I was heavily inspired to make my own cool visual effect as well. I decided to start by learning a tool called VFX Graph (within Unity). This is different from the Particle System previously used for sand simulations. I wanted to see if I could make cool things with it.

After watching a tutorial to get me started with this feature, I had managed to create a simple effect, while understanding how the VFX graph works.

Killing two birds with one stone: Learnt a new tool and made myself a screensaver

To create the effect of my name appearing in the title GIF, I first had a model of my name as a 3D text mesh in Maya.

I imported it into Unity as an .fbx file.

Then, I created a basic particle emitter to emit in a rectangle.

Then using a tool, I created a Signed Distance Field (SDF) of my name. I think of an SDF as a texture, but instead of storing colors in each pixel, it stores directions. It is like a wind current. Any air particle that gets caught in the wind will flow along it.

Imagine the above, but in a 3D volumetric representation, so there are 3D arrows in space telling how particles should move. This is how I control seemingly random particles to flow into the direction or into a space I want them to go to.

By assigning the SDF file as input into the VFX emitter, and adjusting how much I want the particles to ‘stick’ to the SDF, I create the effect below.

After writing some code, I exposed the parameters of the VFX graph to be editable in real-time, without having to simulate the entire VFX every time an attribute is changed.

I added interactive sliders at the top right to allow myself or anyone to play with my VFX

For those interested, here is how the Signed Distance Field part of my VFX graph looks like:

A portion how the VFX graph looks like, focused on the SDF node on the right side

The VFX Graph is a node-based system, meaning no programming is required unless you wish to add interactivity. The pros of the VFX Graph is that it is heavily optimized and able to simulate millions of particles in real-time.

Having learnt this earlier on, there could be options that could be explored for this project – for example, using VFX to materialize our compass or the chinese symbols in our earlier video draft.

For reference, I used this SDF baker tool to assist me in generating the Signed Distance Field asset within Unity, without going through an external DCC like Houdini, reducing the need to jump through multiple software.