Editing Mesh Vertices and Trigonometry - CLOSED - Solved

Scripting
1

Before everything, please refer to the image attached to help you follow up my explanation.

I have a box that I created procedurally (actually, its more complex then a box, but lets assume its a box for simplification purposes), and I want to make it look that it was ‘cut’ at an angle. In order to do that, I must move the mesh vertices along the Z axys, forward or backwards, depending on the angle given.

This is the code that I use to do so:

Mesh mesh = GetComponent<MeshFilter>().mesh;

Mesh mesh = GetComponent<MeshFilter>().mesh;
    
Vector3[] verts = mesh.vertices;

        for(int i = 0; i < verts.Length; i++)
        {
                float newZ = center.z + (verts[i].z - center.z) * Mathf.Cos(angle) - (verts[i].y - center.y) * Mathf.Sin(angle);
        }
        verts[i].Set(verts[i].x, verts[i].y, newZ);[/INDENT]
        mesh.vertices = verts;

The problem with this code is that it clamps the slicing angle between 45 to 135 (a 90º angle). So, if I want to slice it at a 30º, it will slice it at 45º, and so on. You get the point.

Any ideias?

2301016--154908--Untitled-1.png
2301016--154908--Untitled-1.png582×654 6.64 KB

2

2 things

  1. You Shouldn’t compare floats with ==. Use Mathf.Approximately [Float precision errors]
  2. You create a newX variable, and never assign it to anything

also, aren’t you calculating a new z value for the verts?
I don’t really understand the brief

3

You are right, I was missing a line of code. Changed it a litle so it avoids confusing more people. Please take another look.

4

I’ve uploaded my project file, along with a PDF explaining a litle better what I need it to do. Please take a look at both of them.

https://dl.dropboxusercontent.com/u/20794300/Problem.rar

5

it will not work as you expected with only two vertices of one edge!! you need a third one, depend on which vertex you are dragging!!

you need to find the median at this vertex, let says you are moving V0 which is connected to V1 and V3

Vmedian = (V0V1 + V0V3).normalized

once you find the median, you need to change the vertices of the egde V0V1 and V0V3 at this corner through the median direction

let me know if you need more help

6

Solved!
The code wasn’t

float newZ = center.z + (verts[i].z - center.z) * Mathf.Cos(angle) - (verts[i].y - center.y) * Mathf.Sin(angle)

But

float newZ = (Mathf.Abs(verts[i].y) / Mathf.Tan(local_angle * Mathf.Deg2Rad));

I was using Sin as Cos when what I should have been using Tan
:wink: