How to make a stencil shader only affect a certain object?

I'm working on a building designer and I'm using two planes with stencil shaders to cut holes in the walls for each window, one back and one front facing. The problem is that the stencils affect wall sections other than the ones the window is attached to, causing this x-ray effect on the corners. Is there a property I can set when I create the object to tell it to only affect the wall section in its parent?

I appreciate any insight, shaders are forbidden magic to me.


Shader on the stencil planes:

Code (CSharp):

1.  
2. Shader "Mask"
3. {
4.    //show values to edit in inspector
5.    Properties{
6.        [IntRange] _StencilRef("Stencil Reference Value", Range(0,255)) = 0
7.    }
8.  
9.        SubShader{
10.        //the material is completely non-transparent and is rendered at the same time as the other opaque geometry
11.        Tags{ "RenderType" = "Opaque" "Queue" = "Geometry-1"}
12.  
13.        //stencil operation
14.        Stencil{
15.            Ref[_StencilRef]
16.            Comp Always
17.            Pass Replace
18.        }
19.  
20.        Pass{
21.                //don't draw color or depth
22.                Blend Zero One
23.                ZWrite Off
24.  
25.                CGPROGRAM
26.                #include "UnityCG.cginc"
27.  
28.                #pragma vertex vert
29.                #pragma fragment frag
30.  
31.                struct appdata {
32.                    float4 vertex : POSITION;
33.                };
34.  
35.                struct v2f {
36.                    float4 position : SV_POSITION;
37.                };
38.  
39.                v2f vert(appdata v) {
40.                    v2f o;
41.                    //calculate the position in clip space to render the object
42.                    o.position = UnityObjectToClipPos(v.vertex);
43.                    return o;
44.                }
45.  
46.                fixed4 frag(v2f i) : SV_TARGET{
47.                    return 0;
48.                }
49.  
50.                ENDCG
51.            }
52.    }
53. }

Shader on the wall sections:

Code (CSharp):

1.  
2. Shader "WallShaderDefault" {
3.    Properties{
4.        _Color("Tint", Color) = (0, 0, 0, 1)
5.        _MainTex("Texture", 2D) = "white" {}
6.        _Smoothness("Smoothness", Range(0, 1)) = 0
7.        _Metallic("Metalness", Range(0, 1)) = 0
8.        [HDR] _Emission("Emission", color) = (0,0,0)
9.  
10.        [IntRange] _StencilRef("Stencil Reference Value", Range(0,255)) = 0
11.    }
12.        SubShader{
13.            Tags{ "RenderType" = "Opaque" "Queue" = "Geometry"}
14.  
15.            //stencil operation
16.            Stencil{
17.                Ref[_StencilRef]
18.                Comp Equal
19.            }
20.  
21.            CGPROGRAM
22.  
23.            #pragma surface surf Standard fullforwardshadows
24.            #pragma target 3.0
25.  
26.            sampler2D _MainTex;
27.            fixed4 _Color;
28.  
29.            half _Smoothness;
30.            half _Metallic;
31.            half3 _Emission;
32.  
33.            struct Input {
34.                float2 uv_MainTex;
35.            };
36.  
37.            void surf(Input i, inout SurfaceOutputStandard o) {
38.                fixed4 col = tex2D(_MainTex, i.uv_MainTex);
39.                col *= _Color;
40.                o.Albedo = col.rgb;
41.                o.Metallic = _Metallic;
42.                o.Smoothness = _Smoothness;
43.                o.Emission = _Emission;
44.            }
45.            ENDCG
46.        }
47.            FallBack "Standard"
48. }

 

I'm having exactly the same problem. Did you find a solution?