unity建筑物生长切片动画

效果如下图：

对应shader如下，将对应模型材质shader替换为下文shader

Shader "Custom/ClippingShader"
{
	Properties
	{
		_Color("Color", Color) = (1,1,1,1)
		_MainTex("Albedo (RGB)", 2D) = "white" {}
		_Glossiness("Smoothness", Range(0,1)) = 0.5
		_Metallic("Metallic", Range(0,1)) = 0.0


	   [HDR] _CutoffColor("Cutoff Color",Color) = (1,0,0,0)
	}
		SubShader
		{
			Tags { "RenderType" = "Opaque" }


			LOD 200

			Cull off

			CGPROGRAM
			// Physically based Standard lighting model, and enable shadows on all light types
			#pragma surface surf Standard fullforwardshadows

			// Use shader model 3.0 target, to get nicer looking lighting
			#pragma target 3.0

			sampler2D _MainTex;


		   float4 _Plane;
		   float4 _CutoffColor;

			struct Input
			{
				float2 uv_MainTex;
				float3 worldPos;
				float facing : VFACE;
			};

			half _Glossiness;
			half _Metallic;
			fixed4 _Color;

			void surf(Input IN, inout SurfaceOutputStandard o)
			{
				float distance = dot(IN.worldPos, _Plane.xyz);
				distance = distance + _Plane.w;

				clip(-distance);

				float facing = IN.facing*0.5 + 0.5;

				// Albedo comes from a texture tinted by color
				fixed4 c = tex2D(_MainTex, IN.uv_MainTex) * _Color;
				o.Albedo = c.rgb;
				// Metallic and smoothness come from slider variables
				o.Metallic = _Metallic;
				o.Smoothness = _Glossiness;
				o.Alpha = c.a;
			}
			ENDCG
		}
			FallBack "Standard"
}

对应C#脚本如下，将模型中对应材质赋值给下面脚本中，然后修改挂载此脚本的物体的y值，即可实现此效果

using UnityEngine;

public class ClippingPlane : MonoBehaviour
{
    public Material[] materials;

    private void Update()
    {
        Plane plane = new Plane(transform.up, transform.position);
        Vector4 planeVisulization = new Vector4(plane.normal.x, plane.normal.y, plane.normal.z, plane.distance);
        for (var i = 0; i < materials.Length; i++)
        {
            materials[i].SetVector("_Plane", planeVisulization);
        }
    }
}

如果你感觉手动赋值materials比较麻烦，可以写一个编辑器工具，自动搜索项目中对应的材质，然后赋值到materials中即可。
对应的测试工程在这里