Animated Shape missing motion Blur

[Mrodvfx]

Got an issue with an Animated (Grouped) shape.

Motion blur from the tyflows motion(speed) is just fine.
However the animation in the grouped object is missing.

The object in question is a drone with spinning propellers. 
Propellers have no motion blur.

Attached an image detailing this issue:
   
2 drones on top are tyflow instances
1 drone at the bottom is object.

You can see the motion blur on the objects propellers is working as expected.
But not with tyflows, and just to make sure motion blur was working I added some speed to them, so you can see that tyflow is calculating some motion blur.

Tried a lot of different variations of settings including the following:
Time step 1/4 1/6 etc
Vray instance on / off (same with meshing node)
Speed variations in shapes animation

Not sure where to go from here

[tyFlow]

Your blades are probably spinning so fast, that straight linear motion blur interpolation (the type that tyFlow uses for the Shape operator) is giving you no motion blur. Think of it like this: if a blade spins around 360 degrees in 1 frame, the difference between its start orientation and end orientation is essentially zero, even though it's traveled around in a full circle. tyFlow doesn't know about its travel path, only that it started and ended in the same place, hence no motion blur. Normal transform (object) motion blur can account for this, because those sub-frames will get sampled by the renderer...but that data isn't retained in the particles, which explains the difference.

You'd definitely need a workaround of some sort to get it working....one example would be to simulate your copters with particles to get their motion, but instead of the particles having your helicopters as shapes, you'd simply link actual helicopter geometry to the particles afterwards using a tyParticleController on their transform. This isn't going to be a great solution if you have hundreds of copters, but for only a few it wouldn't leave you with too heavy/unmanageable of a scene.

[Mrodvfx]

Your blades are probably spinning so fast, that straight linear motion blur interpolation (the type that tyFlow uses for the Shape operator) is giving you no motion blur. Think of it like this: if a blade spins around 360 degrees in 1 frame, the difference between its start orientation and end orientation is essentially zero, even though it's traveled around in a full circle. tyFlow doesn't know about its travel path, only that it started and ended in the same place, hence no motion blur. Normal transform (object) motion blur can account for this, because those sub-frames will get sampled by the renderer...but that data isn't retained in the particles, which explains the difference.

You'd definitely need a workaround of some sort to get it working....one example would be to simulate your copters with particles to get their motion, but instead of the particles having your helicopters as shapes, you'd simply link actual helicopter geometry to the particles afterwards using a tyParticleController on their transform. This isn't going to be a great solution if you have hundreds of copters, but for only a few it wouldn't leave you with too heavy/unmanageable of a scene.

Thanks for the response. And yeah that makes sense regarding linear interpretation of the shape.

Also thanks for the suggestion regarding particle controller..  But my scene has literally thousands of these spinning blades..  So not the best solution all things considered.. My work around right now is an animated texture on a plane in place of the rotor. Looks proper, and its fast.. Luckily my hero / close up copters are all animated directly not in tyflow, it all works.

Thanks again