Why don't Blender's motion curves update realtime, huh?

Simple question. If you animate you’d probably agree being able to see realtime feedback from the graph editor curves can be helpful when positioning somthing or adjusting it.

Blender does not currently function this way and I’d like to know why, it’s such a simple feature the animators could all benefit from.

Is there a reason? Or is it just negligence? Not meaning that in a negative way FYI, I’m genuinely curious as to why we don’t have it.

Simple question. If you animate you’d probably agree being able to see realtime feedback from the graph editor curves can be helpful when positioning somthing or adjusting it.
Please explain further. If I keyframe the position of an object and change the curve of the location channel in the graph editor I see the effect that change has to the position of the keyframed object in real time as I change that curve

I drop a keyframe at frame 1. I drop a keyframe at frame 10.
With the time slider at frame 10 with the second keyframe, I move the cube in the viewport with the manipulator. The respective motion curve will not update until the movement on the cube is applied, the curve will not move in sync with the cube during the movement.

Donno if you know how, but could you pass this simple feature along up to HQ for me?

I think this would be a great feature to have as well. But your tone makes you come off as an ahole, so please dial the sarcasm meter down a bit. Unless, of course, you like sounding like an ahole. In which case, carry on! Just don’t expect much positive feedback from either the devs or the community.

You’ll have to forgive me, I just came from a forums for a game I play, I’m still in a**hole mode I would assume. Tough place that forum. I’ll be sure to turn the dial down on that.

Anyways, glad we see eye to eye on the matter Mr. fahr.

If not for autokeying being enabled it wouldn’t do anything. To do as you want it would have to continuously replace keys as you move an object. It would require a bunch more code, be a resource hog, and there’s no good reason for this in the typical workflow (place and key then tweak the curves to refine).

This is just a guess.


Resource hog? Maybe an extra percent of CPU power and or RAM, but hardly much.
It would require a “bunch more code” depending on your idea of bunch, though this somewhat depends on how the manipulation tools work already. I do understand your point though, there seems to be some technical issue with it currently.

Just my 2 cents, can’t know for sure unfortunately.

You say motion curves, but there isn’t technically anything by that name in Blender’s animation toolset. I’ve read the replies, and I’m still not sure what’s being talked about. Are you talking about the graph editor f-curves? Or are you talking about motion paths?

F-curves, I’m used to calling them motion curves (in relation to the graph editor.)

Basically, he wants to see the keyframes and curves in the graph editor updating as he moves objects around in the viewport. This can be helpful when animating. I can see how that could be useful. However, I’m not altogether sure why you would expect it work like it’s some obvious simple feature. I do plenty of animation in Maya as well and it doesnt work like you described. In maya (and blender) the graph editor does not update until you plant the object. If you want realtime feedback of your curves, adjust the curves themselves in the graph editor and watch the object update accordingly in the viewport. That’s how I’ve always animated in every package I’ve used and I’ve honestly never really thought about doing it any other way. What other package do you use that does this? Serious question. Sometimes workflows that seem obvious to one person are completely obtuse to another.

Modo has an AMAZING graph editor!
It’s a rather helpful feature!

But it is quite possible to do as you want. Just click on the red button in the Timeline “Automatic keyframe insertion”.

Yeah I really don’t know enough to be commenting on this either. For all I know a script could do the job.

Blender is a garage-built hotrod not a factory cadillac I know that much. Much of the coding is done by volunteers with limited time. Some features just aren’t possible or sensible to code (like a slick feature that is not needed by the majority of users).

If you say the name Aligorith 3 times he will often appear and enlighten us on hows and whys. He is the dev behind much of Blender’s animation system. Aligorith Aligorith.

@Rimpotche: He is inquiring about real-time update of keys/curves while moving an object or bone grabbed in the viewport.


@LP : Sorry, but the Automatic Keyframe does exactly that : update in realtime the curves in the graph editor while you move the objetc or bone in the viewport. What’s the difference ?

Blender just doesn’t work like this by default. Neither to most leading animation packages. If you want something like this use the autokey feature (record button). Its certainly not negligence and it’s pretty arrogant to assume so.

He wants the keys/curves to update continuously while he’s moving an object, not just set keys after he clicks to confirm a transform or when the 3d manipulator handle is released as autokey does. He’d like it to continuously update while he is moving the object in 3D space with the mouse and hasn’t “dropped” it anywhere yet.


You may want to check out the “AnimAide” add-on. It does pretty much what writing about, so if you absolutely need this feature, you can give it a try. Mind you, I’m not vouching or recommending it by any means as I haven’t tried it myself, but it may be something you may be interested in.

Regarding as to why blender doesn’t do this by default, I’d wager that it’s simply a matter of demand. There are about 30 full-time developers for blender, so adding features that aren’t asked for by a lot of users can be counter-productive and add to the waiting time between updates.

It’s also a bit complicated, I think realtime motion curves was in the plans for 2.8 , even editables ones, but the thing is, to make Fcurve interact with 3D view blender only needs to update FCurve drawing and position of bone/object.
For motion path, as there can be a lot of dependency ( parenting, constraints, drivers, vertex parenting ect…) to actually know how the object moves during the whole animation, the only way is to evaluate all animation for every frame and objects that have some relations to the main object.
So they probably find that it was either too error prone to do, or impossible to do given how the dependancy graph works.