Motion blur for native pointlcouds

[Tugcga]

Try to implement motion blur for pointlouds, rendered in native mode (as sphere shapes instead as instances). May be it required define some additional attributes.

Also try to implement motion blur for particles as instances.

[Tugcga]

After some research it turns out that it's not a bug, it's a feature. Native Cycles pointcloud object can be moved by two ways: by changing transform of the root object, and by simulating particles. By default the Cycles use only non-deform motion blur, which defined by changing transform. For render blur of simulated particles it's required to activate Deformation checkbox at Motion tab of the CyclesPointcloud property.

[Tugcga]

Motion blur of ICE-simulated particles rendered incorrectly. The reason in the way to obtain particle positions at time-stamps different from the current render moment.

For motion blur the Sycles loads to the render engine particle positions at several time-stamps. ICE can not calculate proper particle positions before the current time. So, for all these moment it return the current positions. As a result there is no blur effect from previous positions. For next time-stamps it properly simulate particles, and cache it. As a result, if we render the next frame, then all positions before these cached time-stamps will be invalid.

As I understand, it is the problem of the Softimage API. May be there are other methods to obtain particle positions in simulation. But it required more investigations.