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Won't Fix

Votes

3

Found in

5.3.4f1

Issue ID

794020

Regression

No

Graphics.DrawMesh does not handle mirror (negative scale) transforms well, should flip backface culling properly

Graphics - General

-

Steps to reproduce:

1. Open attached project
2. Open scene "Exmaple"
3. Select "Main Camera" and notice that Scale specified in Draw Mesh Scale component uses one negative value
4. Run scene and notice that normals of mesh are messed up

Reproduced with: 5.2.4f1, 5.3.4p6, 5.4.0.b18

Comments (3)

  1. MUGIK

    Jan 25, 2021 18:27

    I had overcome this issue by using this code:

    Matrix4x4 matrix = ... object's localToWorlMatrix ...;
    Vector3 s = matrix.lossyScale;
    bool needToInvertCulling = Mathf.Sign(s.x * s.y * s.z) < 0;
    CommandBuffer.SetInvertCulling( needToInvertCulling );

  2. hedgehog90

    Oct 14, 2016 16:24

    Please add a feature that allows Graphics.DrawMesh to flip normals

  3. z_blush

    May 25, 2016 20:17

    I am running into a similar issue with a skinned 2d character (polygon planes skinned to joints). Here is an example:

    Often, the character is scaled to -1 on X to flip it. The scale happens on the root joint of the character which has no skin influence on the polygons. In this case, all meshes draw perfectly in positive and negative scale space. However, if a child joint which has influence on a mesh is scaled to -1 on X, the affected mesh is drawn in reverse space (the normals are pointing in the opposite direction of the other meshes) - essentially the same problem of backface culling not flipping.

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