How to make wind for effecting plants by physics

suanLoBeach

like wind wave on grasses[

Spinebot

To create a wind effect on plants using physics in Spine, you can utilize the physics constraints feature to simulate wind and gravity. You can set the wind and gravity values directly on the physics constraints to achieve the desired effect. By keying these values, you can modulate them to create a dynamic wind effect. Additionally, you can write code at runtime to control the wind, providing a more random and natural behavior. For a more organic feel, consider slightly varying the apex of your curves so that each bone has different values and spacing, which can enhance the realism of the wind effect.

For more detailed guidance, you might find it helpful to watch tutorials or explore examples of similar effects, such as the windmill tutorial or the Wave principle video.

suanLoBeach

Spinebot so we do not have the feature global wind ?

Nate

We do, check the "global" icon next to wind:

All physics constraints with that checked will use the same timeline. This works will if you have a single set of physics constraints to key together. If you have multiple sets of physics constraints that you want to key differently, you'll have to key the wind for them separately (or use global for one set and key the other set separately).

suanLoBeach

Nate Do I have to set the wind value one by one to achieve the affect in game engine like Unity or Godot ?

Misaki

suanLoBeach You can set the wind value on the physics constraints directly at runtime. If you keyed the wind to the physics constraints, you'd have to change the values after you applied animations.

If you'd rather use an animation, you'd have to create a new animation and timelines, or dig through an existing animation's timelines to find the wind timeline, then you can change the keyed values, add/delete keys, etc. on the wind timeline.

You might want to check out Nate's answer to a question from a user who tried to do something similar with Unity in the past:
https://esotericsoftware.com/forum/d/25363-spine-42-physics-general-questions/12

suanLoBeach

Misaki I do not find out the options about physcis on inspector, so How can I set those keys or value ?

Misaki

suanLoBeach Ah, sorry if my answer was confusing. The Inspector doesn't allow changing constraint properties or adding animation keys. To modify a skeleton's constrained property or add keys, you need to do it in code. This applies not only to physics constraints, but to other elements as well.

If you just want to change the value of the Wind property directly, you can write code like this:

        SkeletonAnimation skeletonAnimation = GetComponent<SkeletonAnimation>();
        PhysicsConstraint constraint = skeletonAnimation.Skeleton.FindPhysicsConstraint("YourConstraintName");
        constraint.Wind = -2.0f;

suanLoBeach

Misaki sorry for the late reply
As what Nate said, I set wind key to global in a skeleton, but I still need to set them one by one for each skeleton characters.

I need real-time dynamic wind to achieve the effect of multiple trees being blown by the same gust of wind, so is using loop to set each skeleton wind value with the code you gave me a correctly mothed ? What I wish is that a wind object can affect all spine skeleton instead of setting one by one.

I want a global physics system in the game world. For example, if I drag and drop a spine skeleton into the game scene, the skeleton will automatically be affected by the wind and gravity in the scene.

Will the future Unity-runtime have a global automatic physics environment ? Is there such a plan?

Nate

If you load a single skeleton data and share it with multiple skeleton instances, you can change the data (which represents the setup pose) and all instances will be affected. See this image:

Skeletons loaded from separate data are always separate, changing one doesn't affect the others. We don't have plans to support global physics. Spine's physics are generally just for animation. A full blown physics engine is a lot more complex and has more features, like collision. Games generally use Box2d or another physics library for gameplay and Spine's physics for animation.

suanLoBeach

Nate Can the spine skeleton use Unity's built-in physics system? Like a ragdoll?

Nate

Yes, you can adjust Spine skeleton bones from Unity GameObjects. See the docs, eg:
http://esotericsoftware.com/spine-unity-utility-components#SkeletonUtilityBone
http://esotericsoftware.com/spine-unity-utility-components#SkeletonRagdoll

suanLoBeach

Nate oh that good, but it could cost more performence, maybe I'll choose spine physics yet