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Regression: Alembic containing animated curves / hair no longer working
Closed, ResolvedPublic

Description

System Information
Win10 x64 Build 1703
nVidia GTX 780 3GB - Latest drivers

Blender Version
Broken: Current Buildbot builds
Worked: Official 2.78c

Short description of error
Importing an Alembic containing animated curves (exported from Blender 2.78c hair dynamics) no longer gives animated curves but just imports the static curves and the SRT animation of the emitter object.
It also throws an error message: "Object type mismatch, Alembic object path points to Curves"
Official 2.78c and Houdini 16 both import the Alembic just fine.

Exact steps for others to reproduce the error

  • New scene, either use the default cube or create a new one
  • Set some animated keyframes on e.g. the location of the cube, just so it moves over time
  • Add a hair emitter to the animated cube
  • Activate dynamics
  • Bake dynamics
  • Export the scene to Alembic (there's another regression with this: Buildbot builds will crash if you set hair "Children" to "Simple" or "Interpolated")
  • New scene
  • Open Alembic (you can also just open the attached file exported from official 2.78c)
  • In 2.78c the strands and the cube are animated and deformed, the only problem is that both the cube and the curves object are parented under an animated empty which results in a doubled animation -> just set the influence of the Transform Cache of this empty to 0.
  • In 2.78.5 from Buildbot the animation of the cube gets imported correctly, no additional empty as a parent. The hair strands also follow the cube but they're no longer deformed but stay in the shape of the first frame.