Do motion blur shutter curves work correctly? I have some problems understanding the motion blur shutter curve. I am near to the point to report a bug, actually ...

What I have done:


use any mesh or the default cube, animate it to move in any direction
go to the middle of the animation (the speed should be max there)
enable motion blur (cycles)
set the shutter curve to an extreme like from bottom left to top right


Now when you render the image, you will see ... well ... I can't tell from the image in which direction the cube is moving. Whatever I set the curve to, I can't tell the direction from a single image. Shouldn't that be obvious? Maybe I misunderstood that functionality.

This is an example of a moving cube with such a shutter curve


I can supply the blend file, if needed.

To clarify what I expected: I expected a (nearly) sharp cube with some trails to the side it is coming from.
I experimented with the shutter curve and it actually works like you expected. I have a Picture here showing tests with different shutter curves:



The white diagramm shows the curve I used for that render. As Object I took the default cube and made it glowing white on black background. I think the main trick to achive the effect that you want is to increase the shutter time to at least 1 (I used 1 for my renders) but that depends on the speeds of your objects in your scene.