TransformInternalWorlds_03

private void CreateTransformedFeatures(IFeatureClass sourceClass, IQueryFilter sourceQF,
IFeatureClass targetClass, IAffineTransformation2D3GEN affineTransformation)
{
    IGeoDataset targetGDS = (IGeoDataset)targetClass;
    IFeatureCursor sourceCur = sourceClass.Search(sourceQF, true);
    IFeature sourceFea = sourceCur.NextFeature();
    while (sourceFea != null)
    {
        // Create the new feature
        IFeature targetFea = targetClass.CreateFeature();

        // Get the source geometry and project to the target spatial reference
        IPolyline sourcePolyline = (IPolyline)sourceFea.ShapeCopy;
        sourcePolyline.Project(targetGDS.SpatialReference);

        // Create a transformed geometry
        IPolyline sourcePolyline = (IPolyline)sourceFea.ShapeCopy;
        ITransform2D transform2D = (ITransform2D)sourcePolyline;
        transform2D.Transform(esriTransformDirection.esriTransformForward,
        (ITransformation)affineTransformation);

        // Assign the transformed geometry
        targetFea.Shape = sourcePolyline;

        // Assign other attributes
        // ...

        targetFea.Store();
        sourceFea = sourceCur.NextFeature();
    }
}