yess

FreeCam/Assets/BlockSpawner.cs

 
 public class BlockSpawner : MonoBehaviour
 {
+
     [SerializeField]
     private GameObject _blockToPlace;
     public GameObject BlockToPlace
 
     public float spawnDistance = 3f;
 
+    public Shader previewShader;
     private GameObject _blockInstance;
 
+
     private bool _isPreview = false;
+    private Shader _initialShader;
 
     public void OnPlaceBlock()
     {
         if (!_isPreview) return;
         _blockInstance.transform.SetParent(null);
+        SwitchToDefaultRender();
         _blockInstance = null;
         DisablePreviewMode();
     }
         _blockInstance = Instantiate(_blockToPlace, spawnPos, Quaternion.identity);
         _blockInstance.transform.SetParent(this.transform, false);
         _isPreview = true;
+        SwitchToMeshRender();
     }
 
     private void DisablePreviewMode()
         if (_blockInstance != null) Destroy(_blockInstance);
         _isPreview = false;
     }
+
+    private void SwitchToMeshRender()
+    {
+        MeshRenderer vRenderer = _blockInstance.GetComponent<MeshRenderer>();
+        Material vMaterial = vRenderer.material;
+        _initialShader = vMaterial.shader;
+        vMaterial.shader = previewShader;
+    }
+
+    private void SwitchToDefaultRender()
+    {
+        MeshRenderer vRenderer = _blockInstance.GetComponent<MeshRenderer>();
+        Material vMaterial = vRenderer.material;
+        vMaterial.shader = _initialShader;
+    }
 }

FreeCam/Assets/BlockSpawner.cs.meta

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+  - previewShader: {fileID: 4800000, guid: 167cdc0b24acc2f449b7fb1756fbc873, type: 3}
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FreeCam/Assets/Effects.meta

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FreeCam/Assets/Effects/NewShaderVariants.shadervariants

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+--- !u!200 &20000000
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+  m_Name: NewShaderVariants
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FreeCam/Assets/Effects/NewShaderVariants.shadervariants.meta

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FreeCam/Assets/Effects/standardSurfaceShader.shader

+Shader "Custom/standardSurfaceShader"
+{
+    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
+    }
+    SubShader
+    {
+        Tags { "RenderType"="Opaque" }
+        LOD 200
+
+        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;
+
+        struct Input
+        {
+            float2 uv_MainTex;
+        };
+
+        half _Glossiness;
+        half _Metallic;
+        fixed4 _Color;
+
+        // Add instancing support for this shader. You need to check 'Enable Instancing' on materials that use the shader.
+        // See https://docs.unity3d.com/Manual/GPUInstancing.html for more information about instancing.
+        // #pragma instancing_options assumeuniformscaling
+        UNITY_INSTANCING_BUFFER_START(Props)
+            // put more per-instance properties here
+        UNITY_INSTANCING_BUFFER_END(Props)
+
+        void surf (Input IN, inout SurfaceOutputStandard o)
+        {
+            // 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 "Diffuse"
+}

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FreeCam/Assets/Effects/wMaillageShader.shader

+Shader "Custom/wMaillageShader"
+{
+    Properties
+    {
+		_MainTex("Texture", 2D) = "white" {}
+		_Color("Color", Color) = (1,1,1,1)
+		_Threshold("Threshold", float) = 0.01
+
+		_EdgeColor("Edge color", Color) = (1,0,0,1)
+
+		_Glossiness("Smoothness", Range(0,1)) = 0.5
+		_Metallic("Metallic", Range(0,1)) = 0.0
+    }
+    SubShader
+    {
+        Cull Off ZWrite Off ZTest Always
+		Tags { "RenderType" = "Opaque" }
+        Pass
+
+		{
+
+			CGPROGRAM
+
+			#pragma vertex vert
+
+			#pragma fragment frag 
+			
+
+			#include "UnityCG.cginc"
+
+			struct appdata
+
+			{
+
+				float4 vertex : POSITION;
+
+				float2 uv : TEXCOORD0;
+
+			};
+
+			struct v2f
+
+			{
+
+				float2 uv : TEXCOORD0;
+
+				float4 vertex : SV_POSITION;
+
+			};
+
+			sampler2D _CameraDepthNormalsTexture;
+			float4 _MainTex_ST;
+
+			v2f vert(appdata v)
+
+			{
+
+				v2f o;
+
+				o.vertex = UnityObjectToClipPos(v.vertex);
+
+				o.uv = TRANSFORM_TEX(v.uv, _MainTex);
+
+				return o;
+
+			}
+
+			sampler2D _MainTex;
+
+			float4 _MainTex_TexelSize;
+
+			float _Threshold;
+
+			fixed4 _EdgeColor;
+
+			float4 GetPixelValue(in float2 uv) {
+
+				half3 normal;
+
+				float depth;
+
+				DecodeDepthNormal(tex2D(_CameraDepthNormalsTexture, uv), depth, normal);
+
+				return fixed4(normal, depth);
+
+			}
+
+			fixed4 frag(v2f i) : SV_Target
+
+			{
+
+				fixed4 col = tex2D(_MainTex, i.uv);
+
+				fixed4 orValue = GetPixelValue(i.uv);
+
+				float2 offsets[8] = {
+
+					float2(-1, -1),
+
+					float2(-1, 0),
+
+					float2(-1, 1),
+
+					float2(0, -1),
+
+					float2(0, 1),
+
+					float2(1, -1),
+
+					float2(1, 0),
+
+					float2(1, 1)
+
+				};
+
+				fixed4 sampledValue = fixed4(0,0,0,0);
+
+				for (int j = 0; j < 8; j++) {
+
+					sampledValue += GetPixelValue(i.uv + offsets[j] * _MainTex_TexelSize.xy);
+
+				}
+
+				sampledValue /= 8;
+
+				return lerp(col, _EdgeColor, step(_Threshold, length(orValue - sampledValue)));
+
+			}
+
+			
+			ENDCG
+		}
+    }
+}

FreeCam/Assets/Effects/wMaillageShader.shader.meta

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FreeCam/Assets/Materials/New Material.mat

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FreeCam/Assets/Scenes/SampleScene.unity

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