I would like to utilize a curve tangent or a curve normal in my driver (i.e. in its Scripted expression)
When working with geometry there's the "Sample Curve" node for that. Is it possible to obtain those values in a property driver?

What I am trying to do:

  1. have my vehicle model follow a path object
    Done - I used the "Follow path" constraint on the vehicle parent object.

  2. have the wheels rotate according to the distance travelled along this path object
    Done - a driver on the "Rotation X" in Delta Transform does that for me. (The driver references the offset of the aforementioned "Follow Path" constraint.)

  3. have the wheels steer/aim according to the tangent (or the normal?) of the curve

  • 1
    $\begingroup$ You could use this technique: Passing GeoNodes attribute to Shader frame offset to read the data in geonodes and pass it to a driver. $\endgroup$ Commented Jul 28, 2023 at 22:53
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    $\begingroup$ The cleanest method might well be case-by-case .. could you give an example of how you want to use the vectors? $\endgroup$
    – Robin Betts
    Commented Jul 29, 2023 at 7:17
  • $\begingroup$ @RobinBetts good point, I am going to update the question elaborate more $\endgroup$ Commented Jul 29, 2023 at 10:48
  • $\begingroup$ @MarkusvonBroady Thanks, that's a step in the right direction! I am not very skilled in Blender, so I don't know yet how to bring the tangent at a point on a path object into the "calculation" part of another object... While the point is determined by a constraint: ${constraints["Follow Path"].offset} $\endgroup$ Commented Jul 29, 2023 at 10:56

1 Answer 1


Only now I realized I can add inputs to my Geometry Node group, and such input can have its own driver:
enter image description here


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