Final Render
Flipbook Previz
Render Process
Final Composite
Raw Render
PreViz
Velocity Breakdown
I created the swirl velocity by calculating the cross product of an up vector and the Normals of a conical geometry. I then transferred the attributes to a point cloud that was big enough to encompass my entire simulation. That gave me the swirly velocity I was looking for, but it needed more refining...
So, I adjusted the incoming velocity to be slower towards the edges of the point cloud and much faster when in the center. I knew I wanted a close up shot of my skull and adding fast moving coins in front of the camera would really help captivate my audience. Also, by adding faster moving coins in the foreground and slower moving coins in the background, it would make the scene feel bigger than what it actually was. However, I ran into my next problem when running the simulation...
The rotational force was pushing all my coins towards the edges of my barrier and flying away. I needed to find a way to bring those coins back in. So, I created a point in the world origin and calculated velocity of my point cloud towards the aforementioned point. This created a force that I wanted but now it was time to combine all my velocities together...
By creating a linear interpolation of all my velocities, I was able to create a vortex that spun around the origin and sucked everything towards the center. It retained a high speed in the middle and slower one in the edge. This really made it feel as if the coins were sinking in the center, as if an invisible hole were sucking them all down with the skull. This setup also gave me control over overall velocity strength, how far to the edges the influence takes effect and how fast they are pulled to the center.
Skull Render
Coin Background
Very quickly into the Shot 1 render, I noticed that I didn't have enough coins to cover my background. Simulating more coins would've been too expensive and would increase my simulation/ render times. So, I decided to add a stagnant coin mountain in the background to ensure I fill the frame. A simple point cloud surrounding the borders of the simulation did the trick. I knew that I would be rendering out a ZDepth pass so having the background out of focus really helped sell the illusion of the coin mountain in the background.
Programs Used
