Backface culling in Unity

I've been trying to figure out how to get backface culling to turn off in Unity, since I don't want to waste the polys by making everything have two sides.

I've read in a few places that I need to type something like CullOff in the Pass of the shader...I'm not sure where to type this in to turn it off, and I'm not much of a coder so I don't know where to look.

Any help would be greatly appreciated! Thanks!

 

By default, backface culling is on, which means everything has one side (the back face is culled). You don't want to use Cull Off, except for those cases where you do want to render both sides.

--Eric

 

Yeah, that's exactly what I want.

 

Oh, I misunderstood your question. You can look in the shader source for the particle shaders, for example, because they all have backface culling turned off. Basically it's just putting "Cull Off" in the "SubShader" section.

--Eric

 

Thanks for the help, Eric. Unfortunately I'm still not sure exactly what to do though, mostly because I don't know how to access the "SubShader" section, and I only started using Unity yesterday so I'm not sure where to look. I opened the material up in a script editor and didn't see any culling flags (though I know almost nothing about scripting so I may have overlooked something) and I'm not sure if this is a glitch, but if I select "Edit Shader..." in Unity, nothing pops up

I spent a while looking, because I don't want to be like one of those lazy noobs that expects answers to fall in their lap, but I'm really at a loss of what to do...I understand what you suggested, I'm just not sure where to find any of that stuff. Sorry >__<

 

You can only edit your own custom shaders. However, you can download the source for all the built-in shaders (look at the sticky in the Shaderlab forum). I agree that, generally speaking, duplicating geometry is the best way. It's still good to know how to do the cull off thing for special cases though.

--Eric

 

Ah, I didn't realize there was such a drawback to turning off the culling. I guess I'll try it and see how it looks, but it probably won't be pretty by the sound of it. Thank you for the help guys, I REALLY appreciate it!

 

I totally agree with this post: if you need to have a biface mesh the best way is to duplicate it and flip normals.
This is the right way for so many reasons...

Otherwise you have to code your shader but will not perform so fast.

The only drawback, as they told you, is that you will use twice the memory for the mesh... but usually this is not a problem.

 

Thanks for all the tips guys. It's definitely a lot more apparent that Cull Off won't solve the problem.

I really appreciate all the help! Thank you

 

4 years later,
At this moment with unity 4.X back facing culling off works very good for clothes and hair shaders. just depends on your needs, but if you create a shader and then set the culling off in the subshader section everything works very fine, (at least for me)

 

Hi Daniel, how exactly do I do the alternative. Ctrl+D to duplicate right? And then how do I flip the normals on the duplicate?

 

You would have to do it in your 3D Editor of choice. As far as I know you cannot edit Meshes in Unity, at least not through the editor.

 

so how exactly?

 

hi all I just installed n tried using Unity yesterday...

 

Thanks! You saved me a lot of time. I had the same problem of a "side not appearing".
Flipping the normals solved this.

A method showing how to do this can be found at:
http://wiki.unity3d.com/index.php/ReverseNormals

Thanks.

 

I read all the comments and answer for this particular question and i agree to most of it. What if someone is doing vertex paint and want its plane to be double sided then how can we do that?? How can we make a plane double side to do vertex painting in Unity???!!!

 

I am so sick of saying this, but please DO NOT bring back to life threads that are 2 years old.

 

I found this thread trying to find out how to turn off culling in a shader in Unity 2018.x. I'm getting 'shader compile errors' when I try the 'Unity 5' method. Anyways, someone online recommended duplicating all the faces and fliping them over as a solution, but doubling the model size isn't wise. I will keep looking for a 2018 (or now 2019) shader that has back-face culling turned off, but if anyone needed the culling turned off for Unity 5 then I'll post the basic Standard Shader (Unity 5 version) with culling turned off. You can make the same change to any shader, just put the Cull Off in the sub-shader section. (Note: Standard Shaders might vary from version to version, this shader seems to work with Unity 5, but not with Unity 2018.

(Save as "StandardCullOFF.shader"):

Code (CSharp):

1. Shader "StandardCullOFF"
2. {
3.     Properties
4.     {
5.         _Color("Color", Color) = (1,1,1,1)
6.         _MainTex("Albedo", 2D) = "white" {}
7.    
8.         _Cutoff("Alpha Cutoff", Range(0.0, 1.0)) = 0.5
9.  
10.         _Glossiness("Smoothness", Range(0.0, 1.0)) = 0.5
11.         _GlossMapScale("Smoothness Scale", Range(0.0, 1.0)) = 1.0
12.         [Enum(Metallic Alpha,0,Albedo Alpha,1)] _SmoothnessTextureChannel ("Smoothness texture channel", Float) = 0
13.  
14.         [Gamma] _Metallic("Metallic", Range(0.0, 1.0)) = 0.0
15.         _MetallicGlossMap("Metallic", 2D) = "white" {}
16.  
17.         [ToggleOff] _SpecularHighlights("Specular Highlights", Float) = 1.0
18.         [ToggleOff] _GlossyReflections("Glossy Reflections", Float) = 1.0
19.  
20.         _BumpScale("Scale", Float) = 1.0
21.         _BumpMap("Normal Map", 2D) = "bump" {}
22.  
23.         _Parallax ("Height Scale", Range (0.005, 0.08)) = 0.02
24.         _ParallaxMap ("Height Map", 2D) = "black" {}
25.  
26.         _OcclusionStrength("Strength", Range(0.0, 1.0)) = 1.0
27.         _OcclusionMap("Occlusion", 2D) = "white" {}
28.  
29.         _EmissionColor("Color", Color) = (0,0,0)
30.         _EmissionMap("Emission", 2D) = "white" {}
31.    
32.         _DetailMask("Detail Mask", 2D) = "white" {}
33.  
34.         _DetailAlbedoMap("Detail Albedo x2", 2D) = "grey" {}
35.         _DetailNormalMapScale("Scale", Float) = 1.0
36.         _DetailNormalMap("Normal Map", 2D) = "bump" {}
37.  
38.         [Enum(UV0,0,UV1,1)] _UVSec ("UV Set for secondary textures", Float) = 0
39.  
40.  
41.         // Blending state
42.          _Mode ("__mode", Float) = 0.0
43.          _SrcBlend ("__src", Float) = 1.0
44.          _DstBlend ("__dst", Float) = 0.0
45.          _ZWrite ("__zw", Float) = 1.0
46.     }
47.  
48.     CGINCLUDE
49.         #define UNITY_SETUP_BRDF_INPUT MetallicSetup
50.     ENDCG
51.  
52.     SubShader
53.     {
54.         Tags { "RenderType"="Opaque" "PerformanceChecks"="False" }
55.         LOD 300
56.  
57.         // ------------------------------------------------------------------
58.         //  Base forward pass (directional light, emission, lightmaps, ...)
59.         Pass
60.         {
61.        
62.             Name "FORWARD"
63.             Tags { "LightMode" = "ForwardBase" }
64.  
65.             Blend [_SrcBlend] [_DstBlend]
66.             ZWrite [_ZWrite]
67.             Cull Off //  HERE IS WHERE YOU PUT CULL OFF
68.  
69.             CGPROGRAM
70.             #pragma target 3.0
71.  
72.             // -------------------------------------
73.  
74.             #pragma shader_feature _NORMALMAP
75.             #pragma shader_feature _ _ALPHATEST_ON _ALPHABLEND_ON _ALPHAPREMULTIPLY_ON
76.             #pragma shader_feature _EMISSION
77.             #pragma shader_feature _METALLICGLOSSMAP
78.             #pragma shader_feature ___ _DETAIL_MULX2
79.             #pragma shader_feature _ _SMOOTHNESS_TEXTURE_ALBEDO_CHANNEL_A
80.             #pragma shader_feature _ _SPECULARHIGHLIGHTS_OFF
81.             #pragma shader_feature _ _GLOSSYREFLECTIONS_OFF
82.             #pragma shader_feature _PARALLAXMAP
83.  
84.             #pragma multi_compile_fwdbase
85.             #pragma multi_compile_fog
86.  
87.             #pragma vertex vertBase
88.             #pragma fragment fragBase
89.             #include "UnityStandardCoreForward.cginc"
90.  
91.             ENDCG
92.         }
93.         // ------------------------------------------------------------------
94.         //  Additive forward pass (one light per pass)
95.         Pass
96.         {
97.             Name "FORWARD_DELTA"
98.             Tags { "LightMode" = "ForwardAdd" }
99.             Blend [_SrcBlend] One
100.             Fog { Color (0,0,0,0) } // in additive pass fog should be black
101.             ZWrite Off
102.             ZTest LEqual
103.  
104.             CGPROGRAM
105.             #pragma target 3.0
106.  
107.             // -------------------------------------
108.  
109.  
110.             #pragma shader_feature _NORMALMAP
111.             #pragma shader_feature _ _ALPHATEST_ON _ALPHABLEND_ON _ALPHAPREMULTIPLY_ON
112.             #pragma shader_feature _METALLICGLOSSMAP
113.             #pragma shader_feature _ _SMOOTHNESS_TEXTURE_ALBEDO_CHANNEL_A
114.             #pragma shader_feature _ _SPECULARHIGHLIGHTS_OFF
115.             #pragma shader_feature ___ _DETAIL_MULX2
116.             #pragma shader_feature _PARALLAXMAP
117.  
118.             #pragma multi_compile_fwdadd_fullshadows
119.             #pragma multi_compile_fog
120.  
121.  
122.             #pragma vertex vertAdd
123.             #pragma fragment fragAdd
124.             #include "UnityStandardCoreForward.cginc"
125.  
126.             ENDCG
127.         }
128.         // ------------------------------------------------------------------
129.         //  Shadow rendering pass
130.         Pass {
131.             Name "ShadowCaster"
132.             Tags { "LightMode" = "ShadowCaster" }
133.  
134.             ZWrite On ZTest LEqual
135.  
136.             CGPROGRAM
137.             #pragma target 3.0
138.  
139.             // -------------------------------------
140.  
141.  
142.             #pragma shader_feature _ _ALPHATEST_ON _ALPHABLEND_ON _ALPHAPREMULTIPLY_ON
143.             #pragma shader_feature _METALLICGLOSSMAP
144.             #pragma shader_feature _PARALLAXMAP
145.             #pragma multi_compile_shadowcaster
146.  
147.             #pragma vertex vertShadowCaster
148.             #pragma fragment fragShadowCaster
149.  
150.             #include "UnityStandardShadow.cginc"
151.  
152.             ENDCG
153.         }
154.         // ------------------------------------------------------------------
155.         //  Deferred pass
156.         Pass
157.         {
158.             Name "DEFERRED"
159.             Tags { "LightMode" = "Deferred" }
160.  
161.             CGPROGRAM
162.             #pragma target 3.0
163.             #pragma exclude_renderers nomrt
164.  
165.  
166.             // -------------------------------------
167.  
168.             #pragma shader_feature _NORMALMAP
169.             #pragma shader_feature _ _ALPHATEST_ON _ALPHABLEND_ON _ALPHAPREMULTIPLY_ON
170.             #pragma shader_feature _EMISSION
171.             #pragma shader_feature _METALLICGLOSSMAP
172.             #pragma shader_feature _ _SMOOTHNESS_TEXTURE_ALBEDO_CHANNEL_A
173.             #pragma shader_feature _ _SPECULARHIGHLIGHTS_OFF
174.             #pragma shader_feature ___ _DETAIL_MULX2
175.             #pragma shader_feature _PARALLAXMAP
176.  
177.             #pragma multi_compile ___ UNITY_HDR_ON
178.             #pragma multi_compile ___ LIGHTMAP_ON
179.             #pragma multi_compile ___ DIRLIGHTMAP_COMBINED DIRLIGHTMAP_SEPARATE
180.             #pragma multi_compile ___ DYNAMICLIGHTMAP_ON
181.  
182.             #pragma vertex vertDeferred
183.             #pragma fragment fragDeferred
184.  
185.             #include "UnityStandardCore.cginc"
186.  
187.             ENDCG
188.         }
189.  
190.         // ------------------------------------------------------------------
191.         // Extracts information for lightmapping, GI (emission, albedo, ...)
192.         // This pass it not used during regular rendering.
193.         Pass
194.         {
195.             Name "META"
196.             Tags { "LightMode"="Meta" }
197.  
198.             Cull Off
199.  
200.             CGPROGRAM
201.             #pragma vertex vert_meta
202.             #pragma fragment frag_meta
203.  
204.             #pragma shader_feature _EMISSION
205.             #pragma shader_feature _METALLICGLOSSMAP
206.             #pragma shader_feature _ _SMOOTHNESS_TEXTURE_ALBEDO_CHANNEL_A
207.             #pragma shader_feature ___ _DETAIL_MULX2
208.  
209.             #include "UnityStandardMeta.cginc"
210.             ENDCG
211.         }
212.     }
213.  
214.     SubShader
215.     {
216.         Tags { "RenderType"="Opaque" "PerformanceChecks"="False" }
217.         LOD 150
218.  
219.         // ------------------------------------------------------------------
220.         //  Base forward pass (directional light, emission, lightmaps, ...)
221.         Pass
222.         {
223.             Name "FORWARD"
224.             Tags { "LightMode" = "ForwardBase" }
225.  
226.             Blend [_SrcBlend] [_DstBlend]
227.             ZWrite [_ZWrite]
228.  
229.             CGPROGRAM
230.             #pragma target 2.0
231.        
232.             #pragma shader_feature _NORMALMAP
233.             #pragma shader_feature _ _ALPHATEST_ON _ALPHABLEND_ON _ALPHAPREMULTIPLY_ON
234.             #pragma shader_feature _EMISSION
235.             #pragma shader_feature _METALLICGLOSSMAP
236.             #pragma shader_feature _ _SMOOTHNESS_TEXTURE_ALBEDO_CHANNEL_A
237.             #pragma shader_feature _ _SPECULARHIGHLIGHTS_OFF
238.             #pragma shader_feature _ _GLOSSYREFLECTIONS_OFF
239.             // SM2.0: NOT SUPPORTED shader_feature ___ _DETAIL_MULX2
240.             // SM2.0: NOT SUPPORTED shader_feature _PARALLAXMAP
241.  
242.             #pragma skip_variants SHADOWS_SOFT DIRLIGHTMAP_COMBINED DIRLIGHTMAP_SEPARATE
243.  
244.             #pragma multi_compile_fwdbase
245.             #pragma multi_compile_fog
246.  
247.             #pragma vertex vertBase
248.             #pragma fragment fragBase
249.             #include "UnityStandardCoreForward.cginc"
250.  
251.             ENDCG
252.         }
253.         // ------------------------------------------------------------------
254.         //  Additive forward pass (one light per pass)
255.         Pass
256.         {
257.             Name "FORWARD_DELTA"
258.             Tags { "LightMode" = "ForwardAdd" }
259.             Blend [_SrcBlend] One
260.             Fog { Color (0,0,0,0) } // in additive pass fog should be black
261.             ZWrite Off
262.             ZTest LEqual
263.        
264.             CGPROGRAM
265.             #pragma target 2.0
266.  
267.             #pragma shader_feature _NORMALMAP
268.             #pragma shader_feature _ _ALPHATEST_ON _ALPHABLEND_ON _ALPHAPREMULTIPLY_ON
269.             #pragma shader_feature _METALLICGLOSSMAP
270.             #pragma shader_feature _ _SMOOTHNESS_TEXTURE_ALBEDO_CHANNEL_A
271.             #pragma shader_feature _ _SPECULARHIGHLIGHTS_OFF
272.             #pragma shader_feature ___ _DETAIL_MULX2
273.             // SM2.0: NOT SUPPORTED shader_feature _PARALLAXMAP
274.             #pragma skip_variants SHADOWS_SOFT
275.        
276.             #pragma multi_compile_fwdadd_fullshadows
277.             #pragma multi_compile_fog
278.        
279.             #pragma vertex vertAdd
280.             #pragma fragment fragAdd
281.             #include "UnityStandardCoreForward.cginc"
282.  
283.             ENDCG
284.         }
285.         // ------------------------------------------------------------------
286.         //  Shadow rendering pass
287.         Pass {
288.             Name "ShadowCaster"
289.             Tags { "LightMode" = "ShadowCaster" }
290.        
291.             ZWrite On ZTest LEqual
292.  
293.             CGPROGRAM
294.             #pragma target 2.0
295.  
296.             #pragma shader_feature _ _ALPHATEST_ON _ALPHABLEND_ON _ALPHAPREMULTIPLY_ON
297.             #pragma shader_feature _METALLICGLOSSMAP
298.             #pragma skip_variants SHADOWS_SOFT
299.             #pragma multi_compile_shadowcaster
300.  
301.             #pragma vertex vertShadowCaster
302.             #pragma fragment fragShadowCaster
303.  
304.             #include "UnityStandardShadow.cginc"
305.  
306.             ENDCG
307.         }
308.  
309.         // ------------------------------------------------------------------
310.         // Extracts information for lightmapping, GI (emission, albedo, ...)
311.         // This pass it not used during regular rendering.
312.         Pass
313.         {
314.             Name "META"
315.             Tags { "LightMode"="Meta" }
316.  
317.             Cull Off
318.  
319.             CGPROGRAM
320.             #pragma vertex vert_meta
321.             #pragma fragment frag_meta
322.  
323.             #pragma shader_feature _EMISSION
324.             #pragma shader_feature _METALLICGLOSSMAP
325.             #pragma shader_feature _ _SMOOTHNESS_TEXTURE_ALBEDO_CHANNEL_A
326.             #pragma shader_feature ___ _DETAIL_MULX2
327.  
328.             #include "UnityStandardMeta.cginc"
329.             ENDCG
330.         }
331.     }
332.  
333.  
334.     FallBack "VertexLit"
335.     CustomEditor "StandardShaderGUI"
336. }
337.  

 

Thanks for this, Eric! I found this post via search tonight and it was exactly what I needed,
Derek

 

I read through this twice and still don't know how to access the sub shader section.

 

You have to create a new 'Standard Surface Shader' in Unity, then double click on it to open it in Visual Studio.

 

It's 2020 now, I have Unity 2019 but am using 2018. I had the same problem trying to turn off backface culling. I edited an Unity 2018 shader too include CULL OFF but it didn't seem to work. It did work with Unity 5 shaders though.

Anyways, I found a couple of shaders that have culling off and work in Unity 2018:
https://gist.github.com/unitycoder/469118783af9d2fd0e2b36becc7dd347

Namely, this one:
https://gist.github.com/unitycoder/...dea2b044497bde3b4cf492/Standard-2Sided.shader

I find that CULL OFF is necessary for things like hair and capes or clothing.

 

See? There's still people talking about it in 2019 and 2020. Maybe contribute to the conversation.

Many threads need updating still because they still exist online and appear in web searches but are outdated. Contribute also, or stay quiet and let others converse.

 

I got the 2019.4.10f1 and this shader

https://forum.unity.com/threads/backface-culling-in-unity.48919/#post-3538719

Works like a charm !

Thanks a lot !

 

I got the 2019.4.12 f1 and it worked great! Is there something else similar to test other solution?

 

It's still working, thank you so Much!

 

Any solution for Unity 2021.1?

 

You can switch Cull fuction here in shader.

 

That's for "Shader Graph", and it sounds like the OP is talking about regular shaders. If they were using Shader Graph, they could just turn off culling by default...but then what do you do if you need back-face culling for some models?

*Just as an update about back-face culling in Unity:
I was still having some problems with culling properly shut off in Unity, since some 2-sided shaders turned out to have side-effects like being semi-transparent on one side, or causing some other models to be seen through them even when opaque. To achieve proper double-sided meshes with proper 2-sided shadows, so far my best results have come from using Unity's Nature/Tree Soft Occlusion Leaves shader (built-in). The slider settings will need to be adjusted though.

 

I had this problem, and the easy solution was to go to the material and change shader from Standard to Standard_two_sided.

 

Yes, I thought I had found the same solution years ago, but that shader (and most others) have weird effects you may not have noticed yet, like the backside of the object (with the 2-sided shader) will be semi-transparent. So, for example, if you had a flag with a 2-sided shader, you can now see both sides, but if you look from the other side, the flag is partially transparent. There's also other side effects, like lighting anomalies, etc..

Here's a post about 2-sided shaders where I show screenshots of some errors caused by the 2-sided shaders for Unity:
https://forum.unity.com/threads/how-to-turn-off-back-face-culling.329744/#post-8086097
It shows things like other objects being seen through the 2-sided shader object (like the barn where you can see the fences inside the barn through the walls).