[SOLVED] Plotting values of variables during runtime for comparison (A.I. debugging)

Unity Engine
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Hello, I am building a vehicle and need a way to compare the values of multiple variables across multiple scripts at the same time (and plotted as a function of time).

The problem I experience is that I have no concise method to visualize the changes generated by an AI controller and see how it’s PID loops are making the vehicle respond by overshooting/undershooting.

Currently I use a simple method of adding [Range(-n,+n)] attributes in the inspector, and by watching and comparing the sliders in the inspector panel it makes things easier than watching a stream of numbers in the console moving at hypersonic velocity. However this is limited to the instantaneous values and has no temporal resolution. Also this only allows one gameobject at a time to be observed.

What I need is basic plotting of variables across multiple scripts.
And I don’t think Unity offers this by default, but I won’t let that deter my ambitions (much).

  • Are there any assets that offer simple plotting or other similar features?

  • Would making an in-game “plot gameobject” be a sensible option (eg. using a bunch of line renderes)?

  • I could see this being a very cumbersome task to build, maybe…

  • I am also familiar with Python and Matplotlib and really like the plots it offers.

  • How could I make the two languages/applications work together? I have used sockets in the past but find them tricky. Would having Unity continuously write .txt/.csv files while Python reads and plots them be a good approach?

  • Are there any other plotting programs that might be useful for this?

[SOLVED]
So I stayed up all night and just created a new tool for this task which uses Python and MatPlotLib to plot the values in realtime:

UPyPlot (Download from GitHub)
Unity Python Plotting - Script variables to realtime MatPlotLib visualization

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It’s rather easy to use and works well (but is still very basic). For any value you wish to have plotted, all you must do is add a custom attribute where you declare that variable, then just run the PlotViewer.py file from Python while the game is running. That’s it!

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At present the tool offers some configurability such as:

  • Precision - Number of decimal places for each value in the plot data file.

  • Interval - Rate in seconds which to update plot data file with new values.

  • Max Samples - Maximum lines/history that the plot file should contain.

[UPDATE]
I added an advanced plot viewer to the project that allows selecting between a single plot style where all lines are combined on a single axes and scale, and another where each line is on it’s own individual plot axes:

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Hope this is useful for someone.

1 Like
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This might sound insane, but in theory it could work.

You could save the variable values to a text file. I’ve done it in the past; the Streamwriter is a bit tricky to use, but it’s doable: How to: Write text to a file - .NET | Microsoft Learn

Then, take Excel and import it:

(You’ll have to save times as well). Then you can make a graph inside Excel. Probably not an ideal solution, but I think it might work.

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Thanks for the suggestions, in the end I just decided to use Python to solve this problem. And in the process created a nifty little tool that I decided to make available on GitHub.

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