Problem with python and driver

Question

Hi Wayne,

I use Blender 3.6 and I a problem with the driver "DEF-Wheel_Front.L" (and the others 3 bones) when I write "auto_rotate(0)" in the driver: error Python.

Answer 1 · 2023-07-30T15:50:47Z

Martin Bergwerf replied July 30, 2023 3:50pm

Hi Massimiliano mmazinga ,

That could be almost anything...

Can you please provide a link to your .blend file (after uploading it to Dropbox, Googledrive, or so)?

Answer 2 · 2023-07-31T05:43:01Z

m

replied July 31, 2023 5:43am

Thank you Martin,

here is the file: https://www.dropbox.com/s/d2bjglqffybm2fh/32%20-%20monster-truck_model.21.blend.zip?dl=0

1 love

Answer 3 · 2023-07-31T08:59:57Z

Adrian Bellworthy replied July 31, 2023 8:59am

Solution

The issue is in the naming, it usually is.
The names used in the script need to match exactly to the names of the rig/bones.

Check your spelling of Monster_Truck_RIG, I see an extra t, Montster in several places.
Once you go through and check the spelling of each Monster in the outliner,
right click the y rotation (purple) for each DEF-Wheel, select edit driver, check the expression is correct for each wheel, then click update dependencies.

The wheel rotation should now work correctly.

Thanks Adrian!

1 love

Answer 4 · 2023-07-31T19:24:34Z

m

replied July 31, 2023 7:24pm

Thank you very much

you are right, I had made a lot of mistakes, the fault of my bad English.

Now it works.

👍

1 love

Answer 5 · 2023-08-01T08:12:01Z

Wayne Dixon replied August 1, 2023 8:12am

I'm glad you all got it working.

Tu sei Englese non cativo ma il mio italiano e molte cativo!

(I'm guessing you are Italian, and that you can read my bad grammar and spelling - I may be wrong on both of those things.)

🤜🤛

2 loves

Answer 6 · 2023-08-01T09:46:15Z

Adrian Bellworthy replied August 1, 2023 9:46am

I would never have been able to help solve this problem without your courses Wayne!

1 love

Answer 7 · 2025-01-20T01:03:12Z

I

replied January 20, 2025 1:03am

I had a similar naming issue, and maybe it’s a good idea to document it here so others can benefit from this in the future.

My general spelling was correct, but somehow, in the lesson "Rigging the Wheels", I forgot to include the word "Direction" in every bone name. This was a mistake from the past, so it was quite hard to figure out where the problem was, especially since the Drivers tab didn’t display anything other than "Python error."

To identify where your mistake is, you can go to the Window tab and select "Toggle System Console." Follow the steps in the video, and this console window will show you exactly where your error is.

🍪🙌
👍

1 love