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Inconsistent behavior keyframing animated rigidbodies
Open, Confirmed, MediumPublic


System Information
Operating system: Linux Mint 19.1
Graphics card: Integrated Intel

Blender Version
2.80 ecdd1864d162 2019-02-18
Worked: Blender 2.79

Short description of error
A common (but "hacky") solution to giving objects an initial velocity is keyframing some motion, then keyframing the animated property on a rigidbody object. When keyframing the animated property of a rigidbody object in Blender 2.80, it is impossible to have this type of animation start on frame 1, with a keyframe on location to frame 2, with the animated checkbox toggled from frame 2 to frame 3. This causes the object to get stuck and fall after the keyframed animation ends. If this trick was applied starting on any other frame number, no problems would occur.

Exact steps for others to reproduce the error
Add a cube. Turn on active rigidbody physics.
Set a location keyframe on frame 1.
On frame 2 move the cube a bit and set a location keyframe.
Set a keyframe to the animated property for rigidbody physics to on.
On the next frame turn off animated rigidbodies and keyframe.

The object will move then get stuck and fall. This effect works if you start on any other frame. Also, adding two frames for the motion before setting the keyframe for animated works.

Here is a .blend file with all possible scenarios described



Event Timeline

Sebastian Parborg (zeddb) triaged this task as Confirmed, Medium priority.Feb 19 2019, 1:56 PM