Surface from polygon from TIN

Discussion created by CEBRON on Nov 4, 2011
Hi everobdy....

I have a TIN and a featureClass of polygons.

I want to create a elevation-surface law to describe each polygon.

For each polygon, I do this :

Dim pTinAdvanced As ITinAdvanced = pTin
Dim pEnumTinTriangle As IEnumTinTriangle = pTinAdvanced.MakeTriangleEnumerator(monCasier.Shape.Envelope, esriTinQualification.esriTinInsideDataArea, Nothing)

Dim pTinSurface As ITinSurface = pTin         
Dim masurface2D As Double
pTinSurface.GetPartialVolumeAndArea(CType(maCote, Double), esriPlaneReferenceType.esriPlaneReferenceBelow, pEnumTinTriangle, pProjectedArea:=masurface2D)

However, the calculation is done on the envelopp of the polygon and not on the real shape !!!

How can I do the calculation on the real shape of the polygon and not on this envelopp ?