Houdini already uses Qt for drawing UI overlays, but nor (yet) for compositional guides so I built a small Python tool that calculates the guides mathematically and uses Qt Painter to draw them directly over the viewport while respecting the camera framing and aspect ratio and packaged it into a shelftool for houdini called PhiAxis.

The idea is very simple: open it, choose your guide, check the composition, keep building your scene and move to the next stages of production. (It's not a guarantee for a great shot it's just a helper guide you maybe even want to intentionally BREAK these guides/rules for more interesting storytelling)
I also tested it against frames from films and games that clearly use these composition rules to make sure everything lines up properly.




i know there's a similar bigger tools for this but as far as i know they are paid and more complex than this one

so it's a simple/FREE/lightweight solution
It’s now available on GitHub and Gumroad with a simple double-click installer.
Tested on Houdini 20.5 through 22.

https://github.com/abdulkarimnoah01/PhiAxis [github.com]
https://github.com/abdulkarimnoah01/PhiAxis/releases/tag/v0.8.1 [github.com]
https://noahkarim.gumroad.com/l/phiaxis [noahkarim.gumroad.com]