Avatar body meshes being manipulated wrongly with IK editor

[Rookstun]

Using the manipulator axis on custom avatar bodies produces undesirable effects in the animation editor. The rotations and positions keep forcing themselves into wrong angles when activated and this occurs while dragging the manipulator as well.

Repro
I am animating through the animation editor using R15 bundles that have been imported from the marketplace, as well as my own avatar (That is using a custom avatar body) that I duplicated when spawned in Studio. The manipulator works normally on FK mode, but using it on IK mode and Full Body IK mode causes the bugs to happen.

• This happens even on a blank Studio file, and with all plugins off.

• This does not happen on Roblox’s bundles or the default R15 Blocky Avatar.

• I remember this was not always the case. I believe I first saw the error happening between November and December of 2023.

System Information:
Windows 10
i7-6700k
RTX 3070
32Gb DDR5 RAM
2 SSDs and 2 HDDs

Betas
I am enrolled in every beta except for:

The Updated Docking System
Scripts and Non-Strict by Default

Visual Aid
On my rig copied from spawning

On an imported bundle from the marketplace

Expected behavior

I expect the IK editor to function normally with custom avatar bodies, as it does with the default avatars and default Roblox bundles.

[thirdtakeonit]

Thanks for the report! Just to confirm, we have a ticket filed in our internal database for this issue.

[Rookstun]

It’s been a while, but I managed to find out what was wrong after posing with a dynamic head recently.

The problem was that the pivot positions and pivot orientations of each part in the character was not 0,0,0.

It seems that either the avatar bodies that are being uploaded or the imports from the avatar importer do not have their avatar’s part pivots centered to each part. When animating, this causes the IK calculator in the Animation Editor to go visually crazy due to wrong pivots.

This should at least result in some kind of warning when starting the animation editor.

Solution
To solve it, for each part in a rig to be animated, except for HumanoidRootPart, their part Pivot properties must be seen like this:

You can just shift click to select the affected parts and override the properties.

And this is the result when using the same avatar body my character is using with a dummy rig.