解决了嵌入部分也会布置砖胎膜或土方问题
1.需根据板往相应方向拉伸，创建拉伸体（非实例）
2.根据轮廓创建融合体
3.将两个物体融合
//创建平面
//创建草图平面，文档必须是族文档
Plane plane = app.Create.NewPlane(new XYZ(0, 0, 1), new XYZ(0, 0, 0));
SketchPlane sp = SketchPlane.Create(familyDoc, plane);
Transaction transaction = new Transaction(familyDoc, "0");
transaction.Start();
//创建拉伸并融合
try
{
blend = familyDoc.FamilyCreate.NewBlend(true, curveArray1, curveArray, sp);
Extrusion rectExtrusion = familyDoc.FamilyCreate.NewExtrusion(false, curveArrArraymtjc, spmtjc, 50);
Parameter parameter23 = rectExtrusion.get_Parameter(BuiltInParameter.MATERIAL_ID_PARAM);
Parameter parameter1 = blend.get_Parameter(BuiltInParameter.MATERIAL_ID_PARAM);
fmFamilyManager.AssociateElementParameterToFamilyParameter(parameter1, newParameter);
CombinableElement rect = rectExtrusion as CombinableElement;
CombinableElement bl = blend as CombinableElement;
blendArray.Append(rect);
blendArray.Append(bl);
familyDoc.CombineElements(blendArray);
}