Picking things up

Jen

Hello,

I'm trying to work out the best way to pick objects up while using Spine as my animation system...

As far as I can tell, the best way to do this is to have a pick-up animation where the character's hand can be targeted to a position, have a slot in the character's hand, and then set the appropriate sprite to the slot at runtime. That's all fine.

The bit I'm stuck on is what comes either side of that: is there a workflow anyone can recommend for how to go from having a complex game object in a scene (i.e. a game object with its own scripts attached), to just a sprite while the character is holding it, and back to the game object when you put it down? - The game object needs to be in a very specific position relative to the character for this to work - if it's not, there's a noticeable jump in position when the game object is set inactive, and the sprite is added. There's also the need to track which game object belongs to which sprite (there are hundreds of things that can be picked up) so that if you drop the object, the game object can be activated again.

Is there a different/better way to do this?

And am I right in thinking there's no way for the game object itself to be attached to a slot?

Thanks!

Harald

Jen schrieb
And am I right in thinking there's no way for the game object itself to be attached to a slot?

You can use a BoneFollower component to let any GameObject follow a bone of your skeleton.

Jen schrieb
The game object needs to be in a very specific position relative to the character for this to work - if it's not, there's a noticeable jump in position when the game object is set inactive, and the sprite is added.

This location difference could be compensated in one of these ways:

a) Adjusting the animation. Use a hand-IK IK target to offset the location of your hand during animation. This changes the look of the animation slightly.
b) Adjusting the character position.
- 1) by animation scaling (root motion delta compensation): Scale motion of the previous approaching animation accordingly so that the animation end-point matches up with the target. When using SkeletonMecanim, we offer a SkeletonMecanimRootMotion which offers root motion scale and scripting methods for root motion delta compensation.
- 2) by slowly lerping the current character position to the precise target position over time. This is a simpler version of delta compensation.
c) Adjusting the target item position. E.g. by slowly lerping the current item position to the precise target item position over time.

There's also the need to track which game object belongs to which sprite (there are hundreds of things that can be picked up) so that if you drop the object, the game object can be activated again.

I see no real problem here, you could use many ways to implement this map between a GameObject and a Sprite or sprite name. Either each GameObject template holds a reference to the sprite (by name or reference), or create a central map (via a ScriptableObject perhaps) that maps from GameObject template to Sprite.

Jen

Thanks! I've finally had a chance to implement this - I went with the BoneFollower and c). In case it helps anyone else, this is what I ended up with:

I added a bool to the BoneFollower script so that I could control when it should follow the bone.
I used the SkeletonRenderSeparator to split the player into two layers (far arm/hand and rest of body) so that the object was ordered correctly once the BoneFollower was in use.
The pick up animation is triggered when the player's and object's colliders collide.
I added an event in the Spine project that fires when the player's hand is close to the ground in the pick up animation.
When that event fires in Unity, I tween the object to the holding-in-hand bone over 0.1 seconds.
Once the tween is finished, I activate the BoneFollower, and set the sorting order of the object picked up.
My character has a SortingGroup component on it, so I also parent the object to the character.

It works really well - thanks again.

Harald

Glad it worked, thanks for sharing!