hy.
I have the attached file.
I have a doub on this mesh (mesh2):
<node id="mesh2" name="mesh2">
<instance_geometry url="#mesh2-geometry">
<bind_material>
<technique_common>
<instance_material symbol="material_1_1_0" target="#material_1_1_0ID">
<bind_vertex_input semantic="UVSET0" input_semantic="TEXCOORD" input_set="0"/>
</instance_material>
<instance_material symbol="material_5_4_0" target="#material_5_4_0ID">
<bind_vertex_input semantic="UVSET0" input_semantic="TEXCOORD" input_set="0"/>
</instance_material>
<instance_material symbol="material_9_8_0" target="#material_9_8_0ID">
<bind_vertex_input semantic="UVSET0" input_semantic="TEXCOORD" input_set="0"/>
</instance_material>
<instance_material symbol="material_3_16" target="#material_3_16ID"/>
<instance_material symbol="material_16_15_0" target="#material_16_15_0ID">
<bind_vertex_input semantic="UVSET0" input_semantic="TEXCOORD" input_set="0"/>
</instance_material>
<instance_material symbol="material_7_6_0" target="#material_7_6_0ID">
<bind_vertex_input semantic="UVSET0" input_semantic="TEXCOORD" input_set="0"/>
</instance_material>
<instance_material symbol="material_0_16" target="#material_0_16ID"/>
<instance_material symbol="material_11_19_0" target="#material_11_19_0ID">
<bind_vertex_input semantic="UVSET0" input_semantic="TEXCOORD" input_set="0"/>
</instance_material>
<instance_material symbol="material_8_7_0" target="#material_8_7_0ID">
<bind_vertex_input semantic="UVSET0" input_semantic="TEXCOORD" input_set="0"/>
</instance_material>
<instance_material symbol="material_11_10_0" target="#material_11_10_0ID">
<bind_vertex_input semantic="UVSET0" input_semantic="TEXCOORD" input_set="0"/>
</instance_material>
<instance_material symbol="material_10_9_0" target="#material_10_9_0ID">
<bind_vertex_input semantic="UVSET0" input_semantic="TEXCOORD" input_set="0"/>
</instance_material>
<instance_material symbol="material_12_11_0" target="#material_12_11_0ID">
<bind_vertex_input semantic="UVSET0" input_semantic="TEXCOORD" input_set="0"/>
</instance_material>
<instance_material symbol="material_17_16_0" target="#material_17_16_0ID">
<bind_vertex_input semantic="UVSET0" input_semantic="TEXCOORD" input_set="0"/>
</instance_material>
<instance_material symbol="material_18_17_0" target="#material_18_17_0ID">
<bind_vertex_input semantic="UVSET0" input_semantic="TEXCOORD" input_set="0"/>
</instance_material>
<instance_material symbol="material_15_14_0" target="#material_15_14_0ID">
<bind_vertex_input semantic="UVSET0" input_semantic="TEXCOORD" input_set="0"/>
</instance_material>
<instance_material symbol="material_4_3_0" target="#material_4_3_0ID">
<bind_vertex_input semantic="UVSET0" input_semantic="TEXCOORD" input_set="0"/>
</instance_material>
<instance_material symbol="material_20_20_0" target="#material_20_20_0ID">
<bind_vertex_input semantic="UVSET0" input_semantic="TEXCOORD" input_set="0"/>
</instance_material>
<instance_material symbol="material_2_2_0" target="#material_2_2_0ID">
<bind_vertex_input semantic="UVSET0" input_semantic="TEXCOORD" input_set="0"/>
</instance_material>
<instance_material symbol="material_19_18_0" target="#material_19_18_0ID">
<bind_vertex_input semantic="UVSET0" input_semantic="TEXCOORD" input_set="0"/>
</instance_material>
<instance_material symbol="material_13_12_0" target="#material_13_12_0ID">
<bind_vertex_input semantic="UVSET0" input_semantic="TEXCOORD" input_set="0"/>
</instance_material>
<instance_material symbol="material_14_13_0" target="#material_14_13_0ID">
<bind_vertex_input semantic="UVSET0" input_semantic="TEXCOORD" input_set="0"/>
</instance_material>
<instance_material symbol="material_21_21_0" target="#material_21_21_0ID">
<bind_vertex_input semantic="UVSET0" input_semantic="TEXCOORD" input_set="0"/>
</instance_material>
</technique_common>
</bind_material>
</instance_geometry>
</node>
why so many materials?
and What should I do in my collada importer?
my game engine only accept one effect at once.
What I doing with all those materials