Alex Majewski

I would like to control the handles of keyframes in the Animation Editor panel with Python and set them programmatically. I don't understand the math behind slope/accel.




To give an example, let's say I want to write a script that automatically finds the right length for handles to be approx. one third of the possible length.



Or a script that maps handle presets to the selected keyframes proportionally. Where could I start?

I was only able to figure out that when the slope is 0, accel can be calculated from .time() alone. But I don't know what slope and accel are mathematically.

I'll appreciate any help.

I'm glad you were able to sort it out Last tip just in case you missed it: remember there are two types of Houdini, regular one and qt5 build. I don't know where we're standing at right now, but in the past qt5 was the version that worked better with Wayland. And Houdini 20.5.X QT6 was working extremely well. Qt5 version (and 20.5 QT6) is available right next to the regular one. QT6 uses PySide6 and QT5 uses PySide2 which will be important for your addons.

When you go to your system login screen, can you switch to X11? Bottom left from the screenshots that I'm seeing online. There should be a dropdown with a list of Wayland and X11. First I'd make sure Houdini starts up on X11. If it does, the error is likely related to Wayland.

As for your error, I don't actually know, but I'm seeing OpenCL and OpenGL in there and those two have been a problem for me multiple times with Houdini. It's possible you might be missing some nvidia packages or environment variables.