how to shade a mesh created in unity

Questions & Answers
1

I used the Mesh class to create a curved wall and it worked well as the shape is exactly what I want. However, the shading is off as you cannot tell the top from the side as I can with a basic cube mesh. I use Vertex-Lit shader and the top of the curved wall is completely flat but does not light up on top like the ther meshes. I use a simple direct light straight down and the camera is looking down from above as well. I might be missing something when i created the curved wall, i did call RecalculateNormals and set the uvs although i dont know which effects the shader. The straight wall is lit like I want. Thank you

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Edit: here is after swapping triangle order in step commented as top 1. Here is my code. I think I have the vertices and triangles but I dont understand the uvs and if I did that right.

var curveMaterial : Material;

function Start() {
CreateCurvedWall(0,0,9,10,0,45,10,0);
}

function CreateCurvedWall( xc : float , zc : float, r1 : float, r2 :float, sa : int, ea : int, ht : int, btm : int) {
var newCurvedWall : GameObject = new GameObject("Curved Wall");
var newMesh : Mesh = new Mesh();
newCurvedWall.AddComponent(MeshFilter);
newCurvedWall.AddComponent(MeshRenderer);
// make vertices
var steps : int = (ea - sa) / 15;
var cnt : int = 0;
var rads : float = 0.0;
var verts : Vector3[] = new Vector3[(steps+1)*4];
var tris : int[] = new int[12+((steps)*24)]; // 4 for ends and 8 per step X 3
for (var i = 0 ; i < (steps + 1); i++) {
    rads = ((i * 15) * Mathf.Deg2Rad);
    verts[cnt] = Vector3(Mathf.Cos(rads)*r1, btm + ht, Mathf.Sin(rads)*r1); cnt++;
    verts[cnt] = Vector3(Mathf.Cos(rads)*r2, btm + ht, Mathf.Sin(rads)*r2); cnt++;
    verts[cnt] = Vector3(Mathf.Cos(rads)*r1, btm, Mathf.Sin(rads)*r1); cnt++;
    verts[cnt] = Vector3(Mathf.Cos(rads)*r2, btm, Mathf.Sin(rads)*r2); cnt++;
}
newMesh.vertices = verts;
// make uvs ?
var uvs : Vector2[] = new Vector2[newMesh.vertices.Length];
for (i = 0 ; i < uvs.Length; i++) {
    uvs <em>= Vector2 (newMesh.vertices_.x, newMesh.vertices*.z);*_</em>
<em>_*}*_</em>
<em>_*newMesh.uv = uvs;*_</em>
<em>_*// make triangles*_</em>
<em>_*cnt = 0;*_</em>
<em>_*tris[cnt] = 0; cnt++; tris[cnt] = 1; cnt++; tris[cnt] = 2; cnt++; //start edge 1*_</em> 
<em>_*tris[cnt] = 1; cnt++; tris[cnt] = 3; cnt++; tris[cnt] = 2; cnt++; //start edge 2*_</em> 
<em>_*for (i = 0 ; i < (steps); i++) {*_</em>
 <em><em>_tris[cnt] = i*4; cnt++; tris[cnt] = (i*4)+6; cnt++; tris[cnt] = (i*4)+4; cnt++; //inner 1_</em></em> 
 <em><em>_tris[cnt] = i*4; cnt++; tris[cnt] = (i*4)+2; cnt++; tris[cnt] = (i*4)+6; cnt++; //inner 2_</em></em>
 <em><em>_tris[cnt] = i*4; cnt++; tris[cnt] = (i*4)+4; cnt++; tris[cnt] = (i*4)+5; cnt++; //top 1_</em></em> 
 <em><em>_tris[cnt] = i*4; cnt++; tris[cnt] = (i*4)+5; cnt++; tris[cnt] = (i*4)+1; cnt++; //top 2_</em></em>
 <em><em>_tris[cnt] = (i*4)+1; cnt++; tris[cnt] = (i*4)+5; cnt++; tris[cnt] = (i*4)+7; cnt++; //outer 1_</em></em> 
 <em><em>_tris[cnt] = (i*4)+1; cnt++; tris[cnt] = (i*4)+7; cnt++; tris[cnt] = (i*4)+3; cnt++; //outer 2_</em></em>
 <em><em>_tris[cnt] = (i*4)+2; cnt++; tris[cnt] = (i*4)+7; cnt++; tris[cnt] = (i*4)+6; cnt++; //bottom 1_</em></em> 
 <em><em>_tris[cnt] = (i*4)+2; cnt++; tris[cnt] = (i*4)+3; cnt++; tris[cnt] = (i*4)+7; cnt++; //bottom 2_</em></em>
<em>_*}*_</em>
<em><em>_tris[cnt] = (steps*4); cnt++; tris[cnt] = (steps*4)+2; cnt++; tris[cnt] = (steps*4)+1; cnt++; //last edge 1_</em></em> 
<em><em>_tris[cnt] = (steps*4)+2; cnt++; tris[cnt] = (steps*4)+3; cnt++; tris[cnt] = (steps*4)+1; cnt++; //last edge 2_</em></em>
<em>_*newMesh.triangles = tris;*_</em>
<em>_*newMesh.RecalculateNormals();*_</em>
<em>_*newCurvedWall.GetComponent(MeshFilter).mesh = newMesh;*_</em>
<em>_*if (curveMaterial) newCurvedWall.renderer.material = curveMaterial;*_</em>
<em>_*newCurvedWall.AddComponent(MeshCollider);*_</em>
<em>_*}*_</em>
<em>_*```*_</em>
2

Maybe the winding order is backwards for the triangle generation, so it's showing the back side of the polygons?

3

After seeing the code, the winding order is fine. You need to split the vertices so that each side has its own set. The way it is now, the lighting is being smoothed over the entire model. You can see a similar effect if you make a cube in a 3D app, then import it into Unity, changing the normals to "Calculate" and using 180 for the smoothing angle.

In order to get hard edges, you need to split vertices. So that particular wall should have 40 vertices (8 top + 8 bottom + 8 left side + 8 right side + 4 front + 4 back) rather than 16. UVs only affect how textures are mapped to vertices, not lighting.