Unity 3d Skyboxes Download ((LINK))

For skybox materials you can go to the Asset Store and download the free Standard Assets for 4.6 from Unity. There should be some other free skyboxes on the Asset store are well, or you can download from the web then create a new material in Unity 5 and select the Skybox shader (supports 6 sides, cube map, procedural) and set the textures.

#pragma surface surf StandardSpecular noambient precision mediump float; uniform vec3 WorldPos; varying vec3 vWorldPos; uniform samplerXY opaque; uniform struct { vec4 CubeTex; vec4 Specular; vec3 Scale; vec3 InvTrans; } Colors; uniform mat4 ProjMtx; varying vec3 VWorldPos; void main() { gl_Position = ProjMtx * vec4(WorldPos, 1.0); vWorldPos = (vec3(WorldPos) * InvTrans).xyz; ivec2 c = ivec2(gl_WorkgroupIndex); ivec4 tex = ff4(c, gl_LocalInvocationID, texCoord); vec4 v0 = texture(opaque, tex2D(CubeTex, vec4(c,gl_PrimitiveID, 0))); vec4 vSpecular = texture(opaque, vec2(tex2D(Specular, c).xy)); vec4 v0Specular = vec4(vSpecular.a * v0.rgb, v0.a); gl_TexCoord[0] *= Colors.CubeTex.rgbw; // recalculate based on new texture, radius and scale gl_FragColor = v0Specular + v0.a; } Pixel Shader : d2c66b5586