check for area test if the face is a triangle.

code/FindDegenerates.cpp

@@ -172,6 +172,7 @@ void FindDegeneratesProcess::ExecuteOnMesh( aiMesh* mesh) {
                     }
                 }
             }
+            if ( face.mNumIndices == 3 ) {
                 ai_real area = calculateAreaOfTriangle( face, mesh );
                 if ( area < 1e-6 ) {
                     if ( configRemoveDegenerates ) {
@@ -182,6 +183,7 @@ void FindDegeneratesProcess::ExecuteOnMesh( aiMesh* mesh) {
                     // todo: check for index which is corrupt.
                 }
             }
+        }
 
         // We need to update the primitive flags array of the mesh.
         switch (face.mNumIndices)