I would like to show the output of an expression and be able to see the plotted graph values of frames in the same way one can in the graph editor.

It seems the Drivers panel will only visualize the custom plotted fCurve element of a driver. I would like to see all of the outputs on the timeline.

The picture below shows two ways of mapping the values of a parameter to a sine curve function. One way uses the function "modifier" to add a built in sine function to the TEST_SINE_2 parameter. The output is clear in the graph editor.

However with expressions it seems there is no way of seeing the output curve. I've been pretty dependent on having this kind of visual feedback for timing keyframes with other software... so this seems like a major hurdle with Blender? The Generator modifier doesn't allow the same possibilities as expressions for Drivers so its pretty limiting to only stick to modifiers.

Does anyone have any ideas for visualizing functions/drivers in a graph editor? I would like to be able to see the output of some more complicated scripted expressions. Would it be possible to write a script that adds a new curve to the Graph editor just for the sake of visualization?

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  • $\begingroup$ This is probably not a feature because it requires evaluating up to an entire scene for all frames. $\endgroup$ Jan 4, 2023 at 20:10
  • $\begingroup$ this might be possible for very easy and basic functions...but try to imagine you are using any values of smoke simulations or other time consuming tasks. Blender would have to calculate the whole simulation before (!) it can show you the visual representation. This would make Blender lag like hell and you don't want that. So...this makes less sense. $\endgroup$
    – Chris
    Jan 5, 2023 at 5:16
  • $\begingroup$ It would be nice if the once evaluated values would be cached, though. Maybe one day. $\endgroup$ Jan 5, 2023 at 9:34
  • $\begingroup$ @Chris I think I see what you mean here. But it seems this would only cause problems if one of the variables in the expression is being pulled from a computationally intensive sim. However, I don't see most linear functions themselves being too computationally intensive. If its a problem of dependencies on external variables, I'm wondering why it isn't at least possible to use the graph modifier to write something like a sawtooth function. $\endgroup$
    – TWheeler
    Jan 6, 2023 at 4:17
  • 1
    $\begingroup$ @MarkusvonBroady Yeah exactly! I'm going to try writing a script that does this. behreajj.medium.com/… $\endgroup$
    – TWheeler
    Jan 6, 2023 at 4:18


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