Nuke's Expression Language - Making Burnins with Tcl
This post is about creating guides in nuke for vendor-side VFX internal reviews. Full demo here and Git Repo with Script here
Introduction
The VFX for Spike Lee's film Highest 2 Lowest were done in large part at Baked Studios in New York City. The film had a long list of camera formats used during shooting and each camera had its own crop factor from plate to what was in the edit. This presented us with a challenge to manage aspect ratios with letterboxing along with these overall crop factors programmatically from shot to shot.
Tcl (Pronounced "Tickle") is a scripting language that Nuke modifies to create an expression language specialized for compositing math. Nuke's Tcl expressions can be used to great effect for simple modifications to knob parameters via mathematical expressions with its syntax.
Baked Studios by the time I left, had a robust python based pipeline integrated with ShotGrid toolkit. Largely built by U.K company Nodes & Layers, this pipeline allowed us to pull data from ShotGrid into nuke for slates, burnins, and various Tcl expressions if needed. The details of this workflow are largely proprietary and out of the scope of this blog post, but I encourage people to reach out to both Baked Studios and Nodes & Layers for details and or services.