Collision on generated mesh

Question

According to the documents, mesh colliders are only constructed when the mesh is placed into the scene.

Is it possible to force a collider component to construct itself based on a mesh filter which you yourself have constructed at runtime? i.e. if geometry changes?

I.e. if I were to make a parametric spiral mesh, for example, and wanted to be able to tweak how many degrees it generates through at run time, and then wanted the result to be collidable, how would I go about that?

If a prefab was instantiated into the scene, and the geometry was constructed in the "Start()" function, would that be early enough to let the mesh collider construct itself?

Or should I add a mesh collider to the game object at runtime after the mesh data is set up?

Answer 1

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Answer by duck · Oct 21, 2010 at 11:26 AM

All you need to do is add the mesh collider component to the same object after you've finished generating the procedural mesh itself. It's fine if it's all in the Start() method. For example:

void Start() {

 // create new Mesh Filter &amp; Mesh objects
 var meshFilter = AddComponent&lt;MeshFilter&gt;();
 var mesh = new Mesh();

 // set up mesh
 mesh.name = name;
 mesh.vertices = myVerts;
 mesh.triangles = myTris;
 mesh.RecalculateNormals();
 meshFilter.mesh = mesh;
 mesh.RecalculateBounds(); 

 // add collider! 
 AddComponent&lt;MeshCollider&gt;();

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Aubrey Hesselgren · Oct 21, 2010 at 11:41 AM 0

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Thank you!

There's no need to point the MeshCollider at the actual mesh, after adding it, or...?

duck ♦♦ · Oct 21, 2010 at 12:17 PM 0

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No, I guess unless you specifically tell it to use another mesh, it uses the same mesh as the MeshFilter object.

If you want to make a lower-res proxy mesh for the collision (while using a higher res mesh for the renderer), you'd have to look into that more closely - or just use separate gameObjects for each :)

Aubrey Hesselgren · Oct 25, 2010 at 09:55 AM 0

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Thanks again duck! Really appreciate the help!

Collision on generated mesh

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