获取REVIT Reference的法向量和原点

// 标记子构件的参考面时，需要依据Reference确定最外侧的标记进行总体标注。如顶部标记的最左侧和最右侧
// 构建参考线，将所有Reference的点向参考线投影，获取最左侧和最右侧Reference
public static bool GetFamilyInstanceReferencePlaneLocation(
    FamilyInstance fi, Reference r,
    out XYZ origin,
    out XYZ normal, bool needTrans=false)
{
    bool found = false;
    origin = XYZ.Zero;
    normal = XYZ.Zero;

    if (null != r)
    {
        Document doc = fi.Document;
        using (Transaction t = new Transaction(doc))
        {
            if (needTrans) t.Start("Create Temporary Sketch Plane");

            using (SubTransaction st = new SubTransaction(doc))
            {
                st.Start();
                SketchPlane sk = SketchPlane.Create(doc, r);
                if (null != sk)
                {
                    Plane pl = sk.GetPlane();
                    origin = pl.Origin;
                    normal = pl.Normal;
                    found = true;
                }

                st.RollBack();
            }

            if (needTrans) t.RollBack();
        }
    }
    return found;
}