unity - Blend Shape - 变形器 - 实践

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目的

拾遗，备份

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Blend Shape 逐顶点 多个混合思路

blend shape 基于： vertex number, vertex sn 相同，才能正常混合、播放
也就是 vertex buffer 的顶点数量一样，还有 triangles 的 index 要一致

这样 blend shape 才能逐个顶点计算

计算公式：使用一张大佬整理的图，大佬的文章：BlendShapes基础与拓展练习（面捕与物体变形）

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Blender

Shift+A 新建一个 sphere

选中

Tab 进入 Editor Mode，并且在 Data 页签属性的 Shape Keys 添加对应的 blend shape 状态

调整好每一个 Shape Keys (或是叫：blend shape) 的顶点位置
然后再 Object Mode 下，我们可以选中对应的 Shape Keys 然后调整 value 查看变形结果

最终我们尝试 K帧动画来查看 多个 shape keys 混合控制的情况

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3Ds max

interlude _1 : working on Yui-chan’s face morphing. - 3Ds max 中的演示 二次元 脸部表情 FFD

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Unity 中使用

先在 blender 导出 fbx

将 fbx 模型拖拽到 hierarchy

尝试拖拉 inspector 中的 blend shape 拉杆，即可查看效果

所以我们写脚本控制 blend shape 混合拉杆即可达到我们各种表情的混合控制

在原来 blendshape_1 基础上在混合 blendshape_2

blendshape_1 和 blendshape_2 一起播放

然后可以尝试看一下 blendshape_1 和 blendshape_2 不同速率的控制混合的情况
这里使用 pingpong 算法

下面是测试 csharp 脚本

// jave.lin 2023/10/07 测试 blend shapeusing System.Collections;
using UnityEngine;public class TestingBlendShape : MonoBehaviour
{public SkinnedMeshRenderer skinnedMeshRenderer;private int _BlendShape_1_IDX = -1;private int _BlendShape_2_IDX = -1;private IEnumerator _couroutine_blendShape1;private IEnumerator _couroutine_blendShape2;private IEnumerator _couroutine_pingpong;private void OnDestroy(){StopAllCoroutines();}private void Refresh(){if (skinnedMeshRenderer != null){_BlendShape_1_IDX = skinnedMeshRenderer.sharedMesh.GetBlendShapeIndex("BlendShape_1");_BlendShape_2_IDX = skinnedMeshRenderer.sharedMesh.GetBlendShapeIndex("BlendShape_2");}}public void ToBlendShape_1(){Refresh();if (_couroutine_blendShape1 != null){StopCoroutine(_couroutine_blendShape1);}StartCoroutine(_couroutine_blendShape1 = Play_ToBlendShape(_BlendShape_1_IDX, 100.0f));}public void ToBlendShape_2(){Refresh();if (_couroutine_blendShape2 != null){StopCoroutine(_couroutine_blendShape2);}StartCoroutine(_couroutine_blendShape2 = Play_ToBlendShape(_BlendShape_2_IDX, 100.0f));}public void ToBlendShape_1_2(){Refresh();if (_couroutine_blendShape1 != null){StopCoroutine(_couroutine_blendShape1);}StartCoroutine(_couroutine_blendShape1 = Play_ToBlendShape(_BlendShape_1_IDX, 100.0f));if (_couroutine_blendShape2 != null){StopCoroutine(_couroutine_blendShape2);}StartCoroutine(_couroutine_blendShape2 = Play_ToBlendShape(_BlendShape_2_IDX, 100.0f));}public void ToPingPong_BlendShape_1_2(){Refresh();if (_couroutine_pingpong != null){StopCoroutine(_couroutine_pingpong);}StartCoroutine(_couroutine_pingpong = PingPong_BlendShape());}public void StopAll(){StopAllCoroutines();}public void ResetAll(){if (skinnedMeshRenderer != null){var count = skinnedMeshRenderer.sharedMesh.blendShapeCount;for (int i = 0; i < count; i++){skinnedMeshRenderer.SetBlendShapeWeight(i, 0.0f);}}}private IEnumerator Play_ToBlendShape(int idx, float to_val){to_val = Mathf.Clamp(to_val, 0.0f, 100.0f);var start_val = skinnedMeshRenderer.GetBlendShapeWeight(idx);var cur_val = start_val;while (cur_val < to_val){cur_val = Mathf.MoveTowards(cur_val, to_val, (to_val - start_val) * Time.deltaTime);skinnedMeshRenderer.SetBlendShapeWeight(idx, cur_val);yield return null;}Debug.Log($"play to blend shape [{idx}] : [{to_val}] complete!");}private IEnumerator PingPong_BlendShape(){var now_time = Time.time;while (true){var _time = Time.time - now_time;var weight1 = Mathf.PingPong(_time * 200f, 100f);var weight2 = Mathf.PingPong(_time * 50f, 100f);skinnedMeshRenderer.SetBlendShapeWeight(_BlendShape_1_IDX, weight1);skinnedMeshRenderer.SetBlendShapeWeight(_BlendShape_2_IDX, weight2);yield return null;}}
}

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Project

个人备份用

• blender 工程: TestingBlenderShapeKeys.blend
• unity 工程: TestingBlendShape_BRP_2020.3.37f1.rar

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• 百人计划-BlendShapes基础（物体变形与面捕应用）
• google : how to implementing the blend shape in blender
• google : how to create shape keys animation in blender
  • Shape Key / Blendshape Hacks to easily create expressions and actions for your avatar
  • Blender 2.8 Shapekeys and Morphing
  • How to Add Shape Keys in Blender
• 形态键
• 在Unity中实现BlendShape表情和骨骼动画混合的实践 - 讲得挺不错
• BlendShapes基础与拓展练习（面捕与物体变形） - 讲得挺不错
• GDC2011: Fast and Efficient Facial Rigging
• GDC jeremy_ernst_fastandefficietfacialrigging.pdf
• 技术美术百人计划-美术 3.5 BlendShape基础 笔记
• 3.5 BlendShapes基础
• 百人计划-BlendShapes基础（物体变形与面捕应用）
• 【技术美术百人计划】美术 3.5 BlendShape基础
• Unity通过导入器优化动画关键帧数据 - 删除仅仅只有 blend shape 的动画的其他骨骼信息，优化性能
• interlude _1 : working on Yui-chan’s face morphing. - 3Ds max 中的演示 二次元 脸部表情 FFD