IK + FlipX breaks animation

Maltakreuz

I have made an running cycle from left to right, using 4 constraints for ankles and feet. It works fine until I flip it by X-axe. That's what happens in Editor:

That's what happens in Unity by this code
skeletonAnimation.skeleton.flipX = true;

(scale.x = -1; just flips the sprite and works fine)

I am not really sure why this happens. Is something wrong with my setup? Or is this a bug/missing feature? Or IK just does not works with FlipX? Essentially i just want a run cycle with flipX, what is the best way to do it in Spine? What disadventages i have if i just use scale.x = -1 in Unity?

Is this related to this topic?

Pharan

Using non-uniform scale in Unity breaks batching and breaks the transforms of non-uniform-scalable child components like many types of colliders. If neither is a concern for you, it should be fine.

So to clarify:
skeleton.flipX causes IK to behave incorrectly in Spine-Unity?

PS
why does her chest have eyes?

BinaryCats

Pharan wrote
Using non-uniform scale in Unity breaks batching and breaks the transforms of non-uniform-scalable child components like many types of colliders. If neither is a concern for you, it should be fine.

So to clarify:
skeleton.flipX causes IK to behave incorrectly in Spine-Unity?

The problem is that the IK is manipulating one bone. this was 'fixed' in all the runtimes, but unity has not received the fix. viewtopic.php?f=9&t=4049&p=19551#p19551

there are other methods of flipping, (i.e. -1 scale on the x axis) but this causes other problems, and will cause you to do a lot of work arounds which would not be present if the IKs flipped correctly.

In the meantime, create 2 bones per ik, even if one bone does nothing, it will fix the problem

Maltakreuz

Pharan wrote
Using non-uniform scale in Unity breaks batching and breaks the transforms of non-uniform-scalable child components like many types of colliders. If neither is a concern for you, it should be fine.

Do you mean a scale of unity "empty object" where Spine-Skeleton is attached to? And what is non-uniform scale exactly? Is 0.4 everywhere ok or not? Anyway to make collider a child of animation is a bad idea, a better approach is make an animation a child, who can change scale. But collider2d and rigidbody2d components are always a parent and will be never scaled. Otherweise unity will recalculate the whold physic.

Pharan wrote
skeleton.flipX causes IK to behave incorrectly in Spine-Unity?

Right. But actually not only in Unity-Spine, in Editor too.

Pharan wrote
why does her chest have eyes?

Because i can 🙂 It's a dummy-test sprite, not final version of character. Anyway she will recieve a clothes/armor in slots.

BinaryCats

Maltakreuz wrote
Pharan wrote
Using non-uniform scale in Unity breaks batching and breaks the transforms of non-uniform-scalable child components like many types of colliders. If neither is a concern for you, it should be fine.

Do you mean a scale of unity "empty object" where Spine-Skeleton is attached to? And what is non-uniform scale exactly? Is 0.4 everywhere ok or not? Anyway to make collider a child of animation is a bad idea, a better approach is make an animation a child, who can change scale. But collider2d and rigidbody2d components are always a parent and will be never scaled. Otherweise unity will recalculate the whold physic.

Pharan wrote
skeleton.flipX causes IK to behave incorrectly in Spine-Unity?

Right. But actually not only in Unity-Spine, in Editor too.

Pharan wrote
why does her chest have eyes?

Because i can 🙂 It's a dummy-test sprite, not final version of character. Anyway she will recieve a clothes/armor in slots.

I think he was referring to scaling by -1 to make the image flip.

yup, its broken in editor too. I image it will be fixed next release as they have fixed it in the runtimes

Maltakreuz

BinaryCats wrote
The problem is that the IK is manipulating one bone. this was 'fixed' in all the runtimes, but unity has not received the fix. viewtopic.php?f=9&t=4049&p=19551#p19551

Oh, thank you. It looks like this is a problem. I will try just to add empty bones. Actually i just copied an approach of raptor, he has identical legs.

For now i just flip the scale in Unity, what problems does it cause?

One thing confuses me: as you can see in Editor legs are flipped incorrectly too. So does not looks like only runtime problem. UPD: OK, then it should really be that. Thank you.

BinaryCats

Maltakreuz wrote
BinaryCats wrote
The problem is that the IK is manipulating one bone. this was 'fixed' in all the runtimes, but unity has not received the fix. viewtopic.php?f=9&t=4049&p=19551#p19551

Oh, thank you. It looks like this is a problem. I will try just to add empty bones. Actually i just copied an approach of raptor, he has identical legs.

For now i just flip the scale in Unity, what problems does it cause?

One thing confuses me: as you can see in Editor legs are flipped incorrectly too. So does not looks like only runtime problem. UPD: OK, then it should really be that. Thank you.

[I will premis this with :I am not a unity user just a 'the Spine tech guy', but we have people here who do use spine + unity ]

If you are using lighting, your character will be unlit as the normal will be the wrong way around. You can write your own shader to combat this though

Maltakreuz

It works 🙂
Btw: single bone should be attached to dummy, not dummy to single bone.