How to Animate Rigid Body Angular Motor Velocity Value?


This is basically a repost of an unanswered stackexchange question:

What it comes down to is that rigid body motors, when set to angular type, have a speed. Is it possible for speed to change based on key frames? So for example if the speed is to smoothly decrease or increase, or even reverse direction, can angular velocity be modified dynamically?

So far I’ve found that if the angular velocity is changed anywhere, then it changes everywhere to the same value. I want a per-frame value.

How to Animate Rigid Body Angular Motor Velocity Value?
(ajcdfin) #2

Hey, maybe try and post this Q in the ‘Particles and Physics’ category.


I just joined the list…can I move this to the Particles and Physics area? Or should I just create a copy of this thread?

(ajcdfin) #4

Not sure about moving it, just post a link to your original thread.


Ok, I added a reference to this in Particles and Physics:

(ruslan k) #6

did you try keyframing the target velocity property within a constraint? (mouseover +i as usual)



I’m new to animation and physics…but I can use key frames to change object orientations…I’ve never found a way to change target velocity. When I do it ignores the key frames and changes to that velocity at all frames. What specific key frame type am I missing?

(ruslan k) #8

as you probably already mentioned the blander acts differently depending on where the mouse pointer is. if you insert keyframe (press i) while the pointer is over 3d view window the blender assumes you’d like to manipulate with object’s rotation/location/scale attribute. but you are not limited with these attributes only. if you move mouse over any property in property window and press i key, then the keyframe for chosen property will be inserted. so you may animate (update by time) this proprty as well. move to other frame, note the property highlighted green (means between frames), update the value then press i again, (became yellow, means keyframed).

switch to Dope Sheet view or Graph Editor to see all the properties being keyframed is keyframed (in left panel)

target-velocity.blend (554.9 KB)


Thank you for the reply! Using the graph editor I am able to do this.

I’m not sure why…probably just doing it wrong…but if I do all else the same and enter the values directly in the target velocity when at a keyframe it simply reverts everywhere. I’d still like to be able to enter the value numerically rather than with a graph though. If I insert a keyframe with the mouse over the target velocity the graph reflects this, but typing in a new value directly to Target Velocity reverts everywhere and keyframes are ignored. Is this correct behavior, or do I need some special key combination to type a numeric value directly into target velocity after a keyframe has been inserted and the timeline is on that frame?

(ruslan k) #10

to apply the new (updated) property value to existing keyframe right-click on the property input
(yellow highlighted area) then select Replace Keyframe from context drop-down


Thank you! This works perfectly, and I learned some useful new things for the future.