Changing a Model to Permanently Adopt a Pose as its Rest Position

This is a Cheat Sheet Guide on how to permanently change a model's Rest Position.

Normally when modelling, we create the model in a T pose and when we finish, we want to change its rest position to a more natural pose for creating animations from or we've download a model that has already been posed where the rest pose is not something we can use to modify it and want to change it to a T or another Pose to make it easier to work with.

This guide will illustrate how to permanently change the armature and mesh so that when we take them into edit mode, the model doesn't spring to a different position (the Rest Pose).

Just remember that if the model has any type of animation using the original armature as its base, those animations will have to be modified or redone to work with the new model.
Changing the rest pose will break pre-made animations that were based on the original model.

Process to change a Model's Rest Position (Blender 2.8x)

So, this is is a review of what I did:

[E7ajamy]

as a matter of fact, i tried the first method you suggested, with SDK models using one of team fortress 2 models. at that time, it worked and i completely dumped it away. i was still beginner not even close to intermediate.

now, i can see high potential trying it both methods. specifically, the second method, and learn or discover a new combination with the two.

[Pte Jack]

Tedious, yes... I know and both are just suggestions without trying.

[E7ajamy]

freak! better something than nothing.


i will try both methods. thank you

[Pte Jack]

As far as I know, you cannot apply any modifier to an object that has shapekeys and I believe that also applies to an armature modifier.
So to be truthful, I'm not sure if you can or not.

That said,
You might be able to Duplicate the model, remove all shapekeys from the duplicate, pose and apply the pose as rest position on the dupe, then transfer your shapes to the dupe from the original
OR,
spit the mesh that has shapes into a separate object. Remove the shapekeys from the object that doesn't need them, pose that object and follow the guide for that object (ie create your A-Pose for the object that doesn't have shapes anymore and set pose as rest position),
then (I can't remember if you can do this off the top of my head) rejoin the mesh that has shapekeys back onto the other object you changed the rest positioning on.

[E7ajamy]

question : i have a model in T pose with shapekeys. i want to change his pose to A pose and apply Pose as Rest Position. how i can do that, without the need to delete shapekeys first?