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Blender can render sub-frames, see: (see: How do I animate time?)

However not all capabilities support this (Fluid-Simulation for example, writes out a discreet mesh per frame, with no subframe interpolation support).


Question: Which animation features in Blender currently don't support sub-frames?

With regard to time-remapping, which is particularly useful for gradual transitions from normal-speed into slow-mo/fast-mo speed).


Note: the Sequencer can do time remapping with the speed strip, but this applies to other kinds of subframe operations too - motion blur for eg.

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While I would like to make a comprehensive list (in one go), this involves quite some research.

Please add in the comments if I miss something.

Subframe Supported

  • FCurves (and anything they animate)
  • Drivers (including the frame variable passed into PyDrivers)
  • Shape Keys (Mesh/Lattice/Curve)
  • Shape Keys (Mask)
  • Curve/Path constraint
  • Rigid-body physics
  • Particles

Subframe Unsupported

  • Movie/Image sequence
  • Fluid-simulation
  • Smoke-simulation
  • Hair-simulation
  • Cloth-simulation
  • Video Sequencer
    Note that while its possible to access sub-frames via the Speed-Effect.
    Exporting subframes from the sequencer it's self is not supported.

Note:

In some cases if subframe support isn't working where it should be- this should be reported as a bug.

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  • $\begingroup$ Rigid body world settings has steps per second (and solver iterations) while particles using newtonian or fluid physics and dynamic paint canvas both have a subframe property. I think subframe support could be broken into two, one is the subframe property that is a fixed extra frame count that would need to be setup to suit, while fcurve type subframes are very dynamic being able to calculate a location for any time step for free. Hair dynamics and cloth have a step value but I don't think that relates to subframes. $\endgroup$
    – sambler
    Aug 31 '15 at 10:40
  • $\begingroup$ The subframe option for physics as for calculation is typically to achieve more stable physics, but not necessarily related to the number of frames stored between frames. (normally the result is to store the result at each frame). $\endgroup$
    – ideasman42
    Aug 31 '15 at 13:17
  • $\begingroup$ I must point out that while some animation features may support sub-frames internally not all of them allow the user to directly manipulate them (via time remapping in NLA or VSE). One way to animate time is via NLA action strips (via strip-time animation), however (to the best of my knowledge) with particle systems you can't use NLA to animate time since you can't create action strips for the particle system animation. So, if the particle systems get to use sub-frames eventually, there must also be a way given to the user to animate time thus actually benefit from a sub-frame extension. $\endgroup$ Aug 31 '15 at 13:55
  • $\begingroup$ With the NLA, you're talking about some finer grained sub-frame support (the ability to take single simulations and change their timing). Thats fine and I can see the use-case. However its a more specialized use-case. $\endgroup$
    – ideasman42
    Aug 31 '15 at 14:04
  • $\begingroup$ I'm having a related issue. I parented a particle emitter to armature bone.The particles come out of a jetpack, leaving a trail as the character flies. It works fine until the character reaches a certain speed, then it becomes apparent that the particles are being emitted only at whole frames and not subframes, making the trail a 'dotted' line instead of continuous. No matter how much I crank up particle count, they bunch up at these 'dots'. If I animate the emitter without parenting to the armature, the trail becomes continuous, but I would like to be able to parent it. $\endgroup$ Apr 21 at 16:52

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