ROI for Action motion blur?

The thing that slows down Action more than anything (at least in my typical uses) is motion blur, and it’s a big slow-down. Curious if it would be feasible and desirable to have an ROI box for motion blur in Action. Very often we only need it in say 1/5th of the frame, but we are paying the tax for 100% of the frame.

Slightly OT but related: would be quite nice to have a more efficient, faster way of selecting which objects do and do not render mblur. If you have a schematic with some 50+ surfaces and gmasks, it takes quite a while. Would be nice to be able to multi-select objects and toggle off or toggle on mblur. The current, manual, object by object process feels quite antiquated…

Something like CTL+Click multiple surfaces in the schematic and a hotkey to toggle Motion Blur on & off? Or a dropdown?

Or were you thinking in the Action Media section, having a checkbox there?

I ask because sometimes you might use different surfaces of the same media input and there could be instances where you want motion blur on one element but not another.

In my dream, it would be an object level selection – so surfaces, gmasks, axes, and 3d objects. Multi-select, then right click for toggle on or off.

Whenever I attempt to deselect motion blur on a layer, it never appears to deselect and continues rendering the blur. Am I doing something wrong?

Check for motion blur key frames

Never use them. They are too fiddly.