Ho questa dichiarazione un pò spartana

codice:
	union 
	{
		struct 	{
					ID3D10Buffer *VertexBuffer;
					ID3D10Buffer *IndexBuffer;
					UINT Indici;
					D3DXMATRIX Objmatr;
					GeneralMaterial Mats;
					unsigned int TextCount; 
				} ColladaBuffer; 

		struct {
					ID3DX10Mesh	*pMesh;
					Material *Materials;
					DWORD Mat;		
				} XBuffer;
	} MeshData;
Ma quando compilo, ottengo il seguente errore

Error 1 error C2620: member 'CMesh::ColladaBuffer' of union 'CMesh::<unnamed-tag>' has user-defined constructor or non-trivial default constructor c:\users\vincenzo\documents\visual studio 2008\projects\colladadom\include\loadmesh.h 73