[求助]谁知道AO中的ITinFilter怎么用？

<P>在求一定范围内TIN的体积时，想通过ITinFilter这个接口获取圈定的范围，但不知道怎么初始化和应用ITinFilter，这是我程序的部分代码，请高手赐教！！</P>

<P>  Dim pTFilter As ITinFilter<BR>  pTFilter.DataElementsOnly = False<BR>  <BR>  Dim pEnumTriangle As IEnumTinTriangle<BR>  Set pEnumTriangle = pTin.MakeTriangleEnumerator(pPoly.Envelope, esriTinInsideDataArea, pTFilter)<BR>  Dim a As Variant, b As Variant, c As Variant<BR> Dim pTinSurface As ITinSurface<BR> Set pTinSurface = pTin.Surface<BR> pTinSurface.GetPartialVolumeAndArea 0, esriPlaneReferenceAbove, pEnumTriangle, a, b, c</P>