Time to Dance

A crash course in expressions for sure.

For this aspect of the shot, we needed a hologram filter, however we hadn’t gotten the plates yet, so frame range, dance, nothing was defined. To get around this, I started working on the filter using my roto project.

Since I wasn’t working on the final plate, I didn’t want to keyframe anything or make the filter only work with my roto project, instead I wanted it to be highly procedural, so I could drop it on to any sequence and have it work. This lead me to learn about nuke expressions.

For those who don’t know what expressions are, expressions are a way to procedurally control the variables of the node. This can be anything from linking a value of one node to another or using mathematic equations to animate a variables value.

So with that understanding, I went at it.

I knew I wanted to make the hologram look decayed, old, left in disrepair. So with that aesthetic locked in, I started by making the “mint condition“ version. I wanted to avoid the classic star wars blue (love Star Wars but want to try a new style, which ended up being a more Halo look), so I gave a bit of an orange and yellow grade with the addition of static lines, cause I love the aesthetic of future tech with the quality of 80s and 90s. With that I started adding different levels of decay, using expressions to animate the values of the different grade and transform sliders to randomise the values. Unfortunately couldn’t get it fully random, so chose to go with different wave functions to animate the values.

During this experiment, I pretty much memorised the Foundry’s page on the mathematical formula for Nuke (find it here). It was easy to read and find the needed the expression, though would like it if it was grouped by function instead of sorted in alphabetical order.

Though I didn’t really touch the variable linking (instancing another variable to the current varrible) I did a lot of that with the use of the colour shuffle node.

But that’s a story for another time

What I Wanted?

I wanted a way to turn any plate footage into a holographic projection. At first I was thinking it would be a few nodes, a couple back drops. That didn’t last long, with it soon becoming a gizmo.

What Changed?

Since I didn’t have the plate for the shot, I started working on a roto I did for a previous uni project. So since I knew that what ever I did would be re used for another plate, I made sure to keep it easy to move around and the best way of doing that was to make the script a gizmo.

What does it Look Like Now?

Well, now instead of being a lot of nodes and back drops, the hologram filter is just one node. Well just a gizmo. I’ve set it up so the the user has plenty of control over the different damage filters and the grade of the damage and hologram.

Are there any next Steps?

Make the gizmo way more user friendly. I would love to make the interface a lot more idiot proof and allow for a great control over the amount of damage in the filter.

Expressions are fun, but having to remember all the functions and wave equations was a bit of a challenge. Maybe I should make a tool that does that for me