Normal Index Array Is Missing!

Hi everyone, I found something interesting,
I just export a polygon plane and polygon sphere both were triangulated.
In DAE file i only see
<triangles material=“initialShadingGroup” count=“200”>
<input semantic=“VERTEX” source="#pPlaneShape1-vertices" offset=“0”/>

0 1 11 1 12 11 1 2 1…</p>
</triangles>

But the normal array is above, here maybe missing such line below
<input semantic=“NORMAL” source="#pPlaneShape1-normals" offset=“1”/>

and the array should be twice big.

Is COLLADA smart enough to know we do not need to ouput normal index array so we can share the vertex index array ?

Is COLLADA smart enough to know we do not need to ouput normal index array so we can share the vertex index array ?
Not exactly. The <vertices> can reference the normals via an <input>, just like it references positions. That’s probably what’s happening in your model. This is an alternative to having the normals <input> adjacent to the <vertices> input in the <triangles> element. An importer should support both.

Steve