# Physics Blend Weight causing jitter **URL:** \ **Category:** World Creation\ **Tags:** content-examples, unreal-engine, Physics, bug-report, question\ **Created:** [January 16, 2016, 11:21am UTC](https://forums.unrealengine.com/t/physics-blend-weight-causing-jitter/344268 "2016-01-16T11:21:25Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![asmrpuppy](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@asmrpuppy](https://forums.unrealengine.com/u/asmrpuppy)\ **Post date:** [January 16, 2016, 11:21am UTC](https://forums.unrealengine.com/t/physics-blend-weight-causing-jitter/344268/1 "2016-01-16T11:21:25Z")
I’m having troubles with using the Physics Blend Weight functionality. When blending between physics and animation, there is a lot of jitter between the two. * * * **How to reproduce** Open the map PhysicsAnimation in the content examples. Slide the Physics Blend Weight slider to 0.5 **What happens** The limbs with physics applied jump around erratically (they have jitter) **What’s expected** The limbs should blend between physics and the animation smoothly. * * * Here’s the documentation on the map and subsequent feature I am referring to: > **[Physics-Based Animation](https://docs.unrealengine.com/4.27/en-US/AnimatingObjects/SkeletalMeshAnimation/PhysicallyDrivenAnimation/)** > > You can blend the results of physics-based animations to ragdoll your characters. Hope anyone can shed any light on why this might be. Best, Minxies ---
**Author:** ![asmrpuppy](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@asmrpuppy](https://forums.unrealengine.com/u/asmrpuppy)\ **Post date:** [January 21, 2016, 11:49pm UTC](https://forums.unrealengine.com/t/physics-blend-weight-causing-jitter/344268/2 "2016-01-21T23:49:17Z")
Really hope someone can throw me a bone with this. I’m really at a loss with it. ---
**Author:** ![Zexus](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Zexus](https://forums.unrealengine.com/u/Zexus)\ **Post date:** [March 26, 2016, 10:06am UTC](https://forums.unrealengine.com/t/physics-blend-weight-causing-jitter/344268/3 "2016-03-26T10:06:39Z")
I came here hoping to find an answer to this, did you figure it out yet ? ---
**Author:** ![hiili](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@hiili](https://forums.unrealengine.com/u/hiili)\ **Post date:** [May 10, 2016, 11:13am UTC](https://forums.unrealengine.com/t/physics-blend-weight-causing-jitter/344268/4 "2016-05-10T11:13:14Z")
I also stumbled on this on engine & content examples version 4.11 (binary release). It definitely seems like a bug in the blending system. Epic, is someone already looking at this? The issue becomes even more pronounced by setting the active animation sequence of the characters to “Idle”. (Select the character → select the SkeletalMesh1 component → set “Anim to Play” to “Idle”) Initially, the characters stand almost still. Moving the blend weight slider even slightly away from 0.0 immediately introduces a steady “jitter” cycle: all affected bones seem to alter between falling freely and snapping back toward an apparently correctly blended pose. On my computer, this cycle runs at around 2-3 times per second. ---
**Author:** ![hiili](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@hiili](https://forums.unrealengine.com/u/hiili)\ **Post date:** [May 10, 2016, 11:24am UTC](https://forums.unrealengine.com/t/physics-blend-weight-causing-jitter/344268/5 "2016-05-10T11:24:38Z")
For others who find this question, the discussion seems to continue here: [Full ragdoll blending + stability - Character & Animation - Unreal Engine Forums](https://forums.unrealengine.com/showthread.php?73797-Full-ragdoll-blending-stability) ---
**Author:** ![UnexpectedSquirt](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@UnexpectedSquirt](https://forums.unrealengine.com/u/UnexpectedSquirt)\ **Post date:** [April 20, 2018, 8:09pm UTC](https://forums.unrealengine.com/t/physics-blend-weight-causing-jitter/344268/6 "2018-04-20T20:09:27Z")
Same issue. I’m stumped. ---
**Author:** ![asmrpuppy](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@asmrpuppy](https://forums.unrealengine.com/u/asmrpuppy)\ **Post date:** [April 20, 2018, 8:35pm UTC](https://forums.unrealengine.com/t/physics-blend-weight-causing-jitter/344268/7 "2018-04-20T20:35:43Z")
This issue can be resolved by using the new PhysicsAnim UActorComponent. You might also want to look at some of the animation solutions in the AnimGraph. ---
**Author:** ![UnexpectedSquirt](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@UnexpectedSquirt](https://forums.unrealengine.com/u/UnexpectedSquirt)\ **Post date:** [April 20, 2018, 9:59pm UTC](https://forums.unrealengine.com/t/physics-blend-weight-causing-jitter/344268/8 "2018-04-20T21:59:17Z")
In my case the issue was resolved by turning off ‘bEnableUpdateRateOptimizations’ on the skeletalmeshcomponent. Apparently this optimization interferes with the physics blending, even when the camera is very close to the mesh.