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Graph Editor generator for angles works in Radians while the graph editor displays the result in degrees.
Confirmed, NormalPublicKNOWN ISSUE


System Information:

Blender Version
Broken: Blender 2.80 Beta (18e5540a48b6) and Blender 2.79 (e290a0b0568e)

Short description of error:
If you use the "generator" modifier in the graph editor for an angle, the generator will work in radians while the graph editor will display the output in degrees.

Exact steps for others to reproduce the error

  1. Open the startup file.
  2. Select the default cube and key frame one of the rotational axis.
  3. Open a graph editor and give the "key framed rotation" an "generator" modifier.
  4. When entering values into the modifier such as 0 and 1 so your polynomial is y=x, the result shown on the graph editor is y=57.3x. This is because the values input to the generator is read as radians while the scale in the graph editor is read in degrees.

Event Timeline

Sebastian Parborg (zeddb) lowered the priority of this task from 90 to 50.

Ah.. just after making the D4458 patch I noticed the assignment @Joshua Leung (aligorith)

From discussions with various people over the years, we've all consistently come to the conclusion that all of these things should always be evaluated in radians only, since that's technically how Blender stores + uses all rotation values internally, and it's also what all the math/trig functions in every standard math library work.

It is only for user convenience that we set the "display units" to degrees, to make it easier for artists to use. Technically, everything is really getting evaluated/interpreted in radians everywhere. In the graph editor, we usually apply some conversions to map between the two as necessary when dealing with rotation curves. Perhaps this case is getting skipped when doing the display unit adjustments when drawing the curve, but I'd have to check carefully to know.

Richard Antalik (ISS) changed the subtype of this task from "Report" to "Known Issue".Jan 24 2020, 8:11 PM

@Sybren A. Stüvel (sybren) Do you believe this could be added to the "quick hacks" project? Or is it too complex? Or is this more of a design task.

@Alaska (Alaska) I can't really tell, it's a UI interface issue and I'm not familiar with the C UI code. It could be fairly simple to let the UI code determine that the FCurve represents an angular value, but then again it may not be.

I've been using 2.82 for a while and I have a bachelors in math. I love radians...when they are written as FRACTIONS.
Nobody knows what the hell these values are in decimals so it REALLY messes up our animation workflow to reverse-engineer stored angles when we need to make changes. Regardless of how these angles are stored internally, they should be displayed in degrees. At the very least, we should be able to enter new values in degrees.