Can I change a bone's parent during animation?

Duré

Just like the title says, can I change the parent of a bone as it's animating?

Example: Sword stays on the hip of your character where it's parent is the hip bone. Character unsheathes the sword and it's parent is now the wrist bone.

I figure I could also accomplish this by duplicating the sword on the hip and the wrist bone, and changing the alpha values at the proper times, but that's probably not ideal.

Søren

Afraid reparenting during animation isn't possible. We decided not to do this to keep the runtimes sane.

I figure I could also accomplish this by duplicating the sword on the hip and the wrist bone, and changing the alpha values at the proper times, but that's probably not ideal.

This is a perfectly ok way to do it.

Later on we might introduce constraints that can be animated, but it will be a while before we can look into it if we go for it.

Duré

Ok, will go ahead and use that strategy then. Really won't be too bad.

Duré

I'm trying to implement this and having issue when switching between animations. My Walk animation has the sword on the hip bone visible, my attack animation has the sword on hand bone visible. I also have an additional Equip animation that modifies the sword bone visibility on hip/hand mid animation.

Currently when I'm in the game and I start walking I see the sword on the hip properly. Then when I attack I see the sword in hand properly. If I go back to walking, the sword never shows on the hip.

My question is: in Spine should I be animating the Slot visibility or the Slot alpha value. Currently I'm getting some strange results using slot visibility. Not sure if I'm using Spine as it wasn't intended though.

Duré

I got it working. You can probably use either approach: slot alpha or slot visibility. Just make sure you key the initial state of your character in the first frame, otherwise it will use the values of the previous animation. To key the Slot visibility you have to go in the hierarchy and press on the dot next to the slot under the key column.

Ctrl+L doesn't key these values. As the Editor hotkey post says, ctrl+L only does SRT values.

Nate

Using slot image visibility (hide the image) is better. Setting an image alpha to zero will still affect your fill rate at runtime as if it drew the entire image.

Duré, for your situation, don't key the sword image visibility in animations except the "equip" animation. Animations only affect bones and slots that have keys.

Duré

Nate wrote
Using slot image visibility (hide the image) is better. Setting an image alpha to zero will still affect your fill rate at runtime as if it drew the entire image.

Duré, for your situation, don't key the sword image visibility in animations except the "equip" animation. Animations only affect bones and slots that have keys.

One thing that concerns me is I would like to support many weapons. If all my weapons are attached to the hand slot, wouldn't I need to key the visibility for each of those images for the equip animation?

Nate

You can key just one weapon image, then programmatically change the key for any weapon you like. Animation has a number of timelines. Find the timeline that is the AttachmentTimeline for the slot index you are interested in. AttachmentTimeline has an array of attachment names, you can change these to the weapon you want to equip. Note animations are shared across multiple skeleton instances, so if you have multiple skeleton instances that could possibly use this animation at the same time with different weapon images, you'll need to have an equip animation instance for each.