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 >__<
If you want your objects to be properly lit, I highly recommend avoiding the Cull Off approach. Basically, Cull Off will get you two-sided geometry with one side lit incorrectly. The work-around is to make complex modifications to existing shaders and take a performance hit due to the extra draw calls.
Unless you are seriously limited by mesh data size, the easiest and best-performing way to render backfaces is to double your mesh and flip the normals on the duplicate.
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!
Reading my post, I don’t think I made it clear that turning culling off is appropriate and faster when you don’t want to do any lighting. As such, it can be useful for special effects or non-photorealistic rendering.
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”):
Shader "StandardCullOFF"
{
Properties
{
_Color("Color", Color) = (1,1,1,1)
_MainTex("Albedo", 2D) = "white" {}
_Cutoff("Alpha Cutoff", Range(0.0, 1.0)) = 0.5
_Glossiness("Smoothness", Range(0.0, 1.0)) = 0.5
_GlossMapScale("Smoothness Scale", Range(0.0, 1.0)) = 1.0
[Enum(Metallic Alpha,0,Albedo Alpha,1)] _SmoothnessTextureChannel ("Smoothness texture channel", Float) = 0
[Gamma] _Metallic("Metallic", Range(0.0, 1.0)) = 0.0
_MetallicGlossMap("Metallic", 2D) = "white" {}
[ToggleOff] _SpecularHighlights("Specular Highlights", Float) = 1.0
[ToggleOff] _GlossyReflections("Glossy Reflections", Float) = 1.0
_BumpScale("Scale", Float) = 1.0
_BumpMap("Normal Map", 2D) = "bump" {}
_Parallax ("Height Scale", Range (0.005, 0.08)) = 0.02
_ParallaxMap ("Height Map", 2D) = "black" {}
_OcclusionStrength("Strength", Range(0.0, 1.0)) = 1.0
_OcclusionMap("Occlusion", 2D) = "white" {}
_EmissionColor("Color", Color) = (0,0,0)
_EmissionMap("Emission", 2D) = "white" {}
_DetailMask("Detail Mask", 2D) = "white" {}
_DetailAlbedoMap("Detail Albedo x2", 2D) = "grey" {}
_DetailNormalMapScale("Scale", Float) = 1.0
_DetailNormalMap("Normal Map", 2D) = "bump" {}
[Enum(UV0,0,UV1,1)] _UVSec ("UV Set for secondary textures", Float) = 0
// Blending state
_Mode ("__mode", Float) = 0.0
_SrcBlend ("__src", Float) = 1.0
_DstBlend ("__dst", Float) = 0.0
_ZWrite ("__zw", Float) = 1.0
}
CGINCLUDE
#define UNITY_SETUP_BRDF_INPUT MetallicSetup
ENDCG
SubShader
{
Tags { "RenderType"="Opaque" "PerformanceChecks"="False" }
LOD 300
// ------------------------------------------------------------------
// Base forward pass (directional light, emission, lightmaps, ...)
Pass
{
Name "FORWARD"
Tags { "LightMode" = "ForwardBase" }
Blend [_SrcBlend] [_DstBlend]
ZWrite [_ZWrite]
Cull Off // HERE IS WHERE YOU PUT CULL OFF
CGPROGRAM
#pragma target 3.0
// -------------------------------------
#pragma shader_feature _NORMALMAP
#pragma shader_feature _ _ALPHATEST_ON _ALPHABLEND_ON _ALPHAPREMULTIPLY_ON
#pragma shader_feature _EMISSION
#pragma shader_feature _METALLICGLOSSMAP
#pragma shader_feature ___ _DETAIL_MULX2
#pragma shader_feature _ _SMOOTHNESS_TEXTURE_ALBEDO_CHANNEL_A
#pragma shader_feature _ _SPECULARHIGHLIGHTS_OFF
#pragma shader_feature _ _GLOSSYREFLECTIONS_OFF
#pragma shader_feature _PARALLAXMAP
#pragma multi_compile_fwdbase
#pragma multi_compile_fog
#pragma vertex vertBase
#pragma fragment fragBase
#include "UnityStandardCoreForward.cginc"
ENDCG
}
// ------------------------------------------------------------------
// Additive forward pass (one light per pass)
Pass
{
Name "FORWARD_DELTA"
Tags { "LightMode" = "ForwardAdd" }
Blend [_SrcBlend] One
Fog { Color (0,0,0,0) } // in additive pass fog should be black
ZWrite Off
ZTest LEqual
CGPROGRAM
#pragma target 3.0
// -------------------------------------
#pragma shader_feature _NORMALMAP
#pragma shader_feature _ _ALPHATEST_ON _ALPHABLEND_ON _ALPHAPREMULTIPLY_ON
#pragma shader_feature _METALLICGLOSSMAP
#pragma shader_feature _ _SMOOTHNESS_TEXTURE_ALBEDO_CHANNEL_A
#pragma shader_feature _ _SPECULARHIGHLIGHTS_OFF
#pragma shader_feature ___ _DETAIL_MULX2
#pragma shader_feature _PARALLAXMAP
#pragma multi_compile_fwdadd_fullshadows
#pragma multi_compile_fog
#pragma vertex vertAdd
#pragma fragment fragAdd
#include "UnityStandardCoreForward.cginc"
ENDCG
}
// ------------------------------------------------------------------
// Shadow rendering pass
Pass {
Name "ShadowCaster"
Tags { "LightMode" = "ShadowCaster" }
ZWrite On ZTest LEqual
CGPROGRAM
#pragma target 3.0
// -------------------------------------
#pragma shader_feature _ _ALPHATEST_ON _ALPHABLEND_ON _ALPHAPREMULTIPLY_ON
#pragma shader_feature _METALLICGLOSSMAP
#pragma shader_feature _PARALLAXMAP
#pragma multi_compile_shadowcaster
#pragma vertex vertShadowCaster
#pragma fragment fragShadowCaster
#include "UnityStandardShadow.cginc"
ENDCG
}
// ------------------------------------------------------------------
// Deferred pass
Pass
{
Name "DEFERRED"
Tags { "LightMode" = "Deferred" }
CGPROGRAM
#pragma target 3.0
#pragma exclude_renderers nomrt
// -------------------------------------
#pragma shader_feature _NORMALMAP
#pragma shader_feature _ _ALPHATEST_ON _ALPHABLEND_ON _ALPHAPREMULTIPLY_ON
#pragma shader_feature _EMISSION
#pragma shader_feature _METALLICGLOSSMAP
#pragma shader_feature _ _SMOOTHNESS_TEXTURE_ALBEDO_CHANNEL_A
#pragma shader_feature _ _SPECULARHIGHLIGHTS_OFF
#pragma shader_feature ___ _DETAIL_MULX2
#pragma shader_feature _PARALLAXMAP
#pragma multi_compile ___ UNITY_HDR_ON
#pragma multi_compile ___ LIGHTMAP_ON
#pragma multi_compile ___ DIRLIGHTMAP_COMBINED DIRLIGHTMAP_SEPARATE
#pragma multi_compile ___ DYNAMICLIGHTMAP_ON
#pragma vertex vertDeferred
#pragma fragment fragDeferred
#include "UnityStandardCore.cginc"
ENDCG
}
// ------------------------------------------------------------------
// Extracts information for lightmapping, GI (emission, albedo, ...)
// This pass it not used during regular rendering.
Pass
{
Name "META"
Tags { "LightMode"="Meta" }
Cull Off
CGPROGRAM
#pragma vertex vert_meta
#pragma fragment frag_meta
#pragma shader_feature _EMISSION
#pragma shader_feature _METALLICGLOSSMAP
#pragma shader_feature _ _SMOOTHNESS_TEXTURE_ALBEDO_CHANNEL_A
#pragma shader_feature ___ _DETAIL_MULX2
#include "UnityStandardMeta.cginc"
ENDCG
}
}
SubShader
{
Tags { "RenderType"="Opaque" "PerformanceChecks"="False" }
LOD 150
// ------------------------------------------------------------------
// Base forward pass (directional light, emission, lightmaps, ...)
Pass
{
Name "FORWARD"
Tags { "LightMode" = "ForwardBase" }
Blend [_SrcBlend] [_DstBlend]
ZWrite [_ZWrite]
CGPROGRAM
#pragma target 2.0
#pragma shader_feature _NORMALMAP
#pragma shader_feature _ _ALPHATEST_ON _ALPHABLEND_ON _ALPHAPREMULTIPLY_ON
#pragma shader_feature _EMISSION
#pragma shader_feature _METALLICGLOSSMAP
#pragma shader_feature _ _SMOOTHNESS_TEXTURE_ALBEDO_CHANNEL_A
#pragma shader_feature _ _SPECULARHIGHLIGHTS_OFF
#pragma shader_feature _ _GLOSSYREFLECTIONS_OFF
// SM2.0: NOT SUPPORTED shader_feature ___ _DETAIL_MULX2
// SM2.0: NOT SUPPORTED shader_feature _PARALLAXMAP
#pragma skip_variants SHADOWS_SOFT DIRLIGHTMAP_COMBINED DIRLIGHTMAP_SEPARATE
#pragma multi_compile_fwdbase
#pragma multi_compile_fog
#pragma vertex vertBase
#pragma fragment fragBase
#include "UnityStandardCoreForward.cginc"
ENDCG
}
// ------------------------------------------------------------------
// Additive forward pass (one light per pass)
Pass
{
Name "FORWARD_DELTA"
Tags { "LightMode" = "ForwardAdd" }
Blend [_SrcBlend] One
Fog { Color (0,0,0,0) } // in additive pass fog should be black
ZWrite Off
ZTest LEqual
CGPROGRAM
#pragma target 2.0
#pragma shader_feature _NORMALMAP
#pragma shader_feature _ _ALPHATEST_ON _ALPHABLEND_ON _ALPHAPREMULTIPLY_ON
#pragma shader_feature _METALLICGLOSSMAP
#pragma shader_feature _ _SMOOTHNESS_TEXTURE_ALBEDO_CHANNEL_A
#pragma shader_feature _ _SPECULARHIGHLIGHTS_OFF
#pragma shader_feature ___ _DETAIL_MULX2
// SM2.0: NOT SUPPORTED shader_feature _PARALLAXMAP
#pragma skip_variants SHADOWS_SOFT
#pragma multi_compile_fwdadd_fullshadows
#pragma multi_compile_fog
#pragma vertex vertAdd
#pragma fragment fragAdd
#include "UnityStandardCoreForward.cginc"
ENDCG
}
// ------------------------------------------------------------------
// Shadow rendering pass
Pass {
Name "ShadowCaster"
Tags { "LightMode" = "ShadowCaster" }
ZWrite On ZTest LEqual
CGPROGRAM
#pragma target 2.0
#pragma shader_feature _ _ALPHATEST_ON _ALPHABLEND_ON _ALPHAPREMULTIPLY_ON
#pragma shader_feature _METALLICGLOSSMAP
#pragma skip_variants SHADOWS_SOFT
#pragma multi_compile_shadowcaster
#pragma vertex vertShadowCaster
#pragma fragment fragShadowCaster
#include "UnityStandardShadow.cginc"
ENDCG
}
// ------------------------------------------------------------------
// Extracts information for lightmapping, GI (emission, albedo, ...)
// This pass it not used during regular rendering.
Pass
{
Name "META"
Tags { "LightMode"="Meta" }
Cull Off
CGPROGRAM
#pragma vertex vert_meta
#pragma fragment frag_meta
#pragma shader_feature _EMISSION
#pragma shader_feature _METALLICGLOSSMAP
#pragma shader_feature _ _SMOOTHNESS_TEXTURE_ALBEDO_CHANNEL_A
#pragma shader_feature ___ _DETAIL_MULX2
#include "UnityStandardMeta.cginc"
ENDCG
}
}
FallBack "VertexLit"
CustomEditor "StandardShaderGUI"
}