Inside mesh transparent

Unity Engine
1

Hi,

I’m having a problem with a 3D model i made in Cinema4D. It’s a pen and there is an animation which screws of the top of the pen. You can rotate around the pen. But when i rotate around the pen i don’t see the insides of the pen.
I now about the normals thing, and i know for sure the normals are all pointing the right way. I also read something about setting Cull off in the shader. So i tried some stuff (i’m not familiar with shader programming) and it won’t work for me.
Here’s the code:

Shader "Custom/ShowAllSides" {
	Properties {
		_MainTex ("Base (RGB)", 2D) = "white" {}
	}
	SubShader {
		Pass{
			Material{
				Diffuse(1,1,1,1)
			}
			Lighting ON
			Cull Off
		}
		CGPROGRAM
		#pragma surface surf Lambert

		sampler2D _MainTex;

		struct Input {
			float2 uv_MainTex;
		};

		void surf (Input IN, inout SurfaceOutput o) {
			half4 c = tex2D (_MainTex, IN.uv_MainTex);
			o.Albedo = c.rgb;
			o.Alpha = c.a;
		}
		ENDCG
	} 
	FallBack "Diffuse"
}

So what am i doing won’t the insides of my mesh show?

2

If you haven’t actuaflly modeled the inside side of pen, and normals are set ouside of pen, you won’t see backface in unity. It’s just the thing of the unity. Also adding cull on/off in shader is not the best decision, because it will screw shading of material. The best solution in this case - model the inside of the pen. You can do this either by duplicating the needed faces and then reversing normal, or by extruding pen inside). One way or another - you need additional geometry.

3

Hi, thx for your reply!

I have the inside of the mesh modeled and the normals are all pointing in the right direction. But still the insides aren’t showing :frowning:

Here is a picture of the mesh in Cinema4D:
http://www.plaatjesdump.nl/upload/990ca78502d2639466326eb924cedd61.png

4

All the normals of the polygons on the inside of the pen appear to be pointing outwards. If you want to see them, you need them to point towards the inside of the pen.

(By default, polygons whose normal point away from the camera are not rendered.)

I think you can fix the problem by using the ‘reverse normals’ function in Cinema4D, on the polygons you added on the inside of the pen.

5

Agree. If your inside faces were facing outwards, you’d see the same lines sticking out of them.