宿迁三台山森林公园花田剧场，一次大型景观建筑的设计挑战。通常景观建筑多为小体量，掩映在景观中。剧场容纳3000座室外观众席，有可遮蔽的屋顶覆盖，体量远大于一般景观建筑。剧场周围绵延五公里三色花海，两公里彩虹桥蜿蜒其间。剧场如何消解较大的体量，融入花海无尽延伸的背景是设计的难点。

▼项目外观，external view of the project

Huatian Theater, built in Mount Santai Forest Park, Suqian, is one design challenge of a large landscape building. Usually landscape buildings are small, melting into the landscape, yet our theater with big volume is to accommodate as much as 3,000 outdoor audiences with a shaded roof covering. Hence, the volume of the Huatian Theater is much larger than general landscape buildings. The tricolor flower sea stretches over five kilometers around the theater with a two-kilometer-long rainbow bridge meandering through it. How to dissipate the large volume of the theater and integrate it properly into the background of the endless flower sea is the key point in the design process.

▼剧场与花海，view of the theater through the flowers

影响剧场体量感的最重要因素是结构选型。常用的拱或悬索等大跨结构形式，在花海当中很容易形成类似体育场或者机场候机楼的印象。分析形成这种感觉的原因，与结构线性的转折拐点多少，线性组合均有关系。曾尝试单元式的分散体量，虽然可以减少体量感，但又很难满足剧场观众视线要求。最终采用自由曲面网架屋面加树枝状支撑结构的形式，暗合花朵和周边树林形态。

▼剧场鸟瞰，aerial view of the theater

The most important factor affecting the sense of volume of the theater is the selection of structure. Large-span structures with arches or suspended cables in the flower sea may easily remind you of a stadium or an airport terminal building. The generation of his feeling is largely related to the number of structural linear turning points and design of the linear combination. Unitary dispersions can reduce the sense of volume yet may not satisfy the audiences of their visual requirements so well. Hence, the form of a freeform surface grid roof plus a dendritic support structure which well echoes with the shape of the flowers and the surrounding woods was finally chosen.

▼剧场结构与周边环境相呼应，the structure of the theater corresponded with the environment

屋面设计的难点是曲面形态控制。造型要求轮廓起伏转折以减少体量感，曲面中部则因为排水方向的限制，需要平滑避免过多凹凸，造成无法排出的内凹面。

▼立面图，曲线屋面通过数字找型，elevations, the shape of the roof was designed by digital method

The difficulty of roof design is surface shape control. An undulated contour is important to reduce the sense of volume, while the restriction of the drainage system in the middle part of the surface requires a relatively plainer rather than a bumpy surface to discharge water as smoothly as possible.

▼曲线屋面减少体量感，the curved roof reduce the impact of the volume

树枝以长度与角度为参数，三级迭代生成树枝，查找就近点确定树枝与屋面网架的连接位置。树枝结构位置最大限度的减少支撑体系对观演视线的影响。

Length and angle as the branches’ parameters，supporting structure and the three-stage iteration of branches are helpful in finding the nearest point which can determine the connecting position between the branches and the grid roof. Moreover, the location of branch structure greatly minimizes the influence of the supporting system on the line of sight.

▼树状支撑分析图，analysis of the treelike structure

屋面三层张拉膜，中间透明膜遮雨，上下两层彩色膜遮阳。彩色膜的三种色彩呼应花田粉，黄，紫三种颜色。彩色膜的选色是设计过程中遇到的又一技术难题。几种正常光线照射下色彩鲜艳的膜，吊挂到屋顶逆光下从下往上看变成了灰色，进行了多次色彩实验，发现网格膜在逆光下的发色反而比光面膜准确。最终选择了网格膜，厂家订制了三种接近花田三色花的特制颜色，与衲田花海呼应。

▼分解轴测图，exploded axonometric

▼三层张拉膜布置图，drawings of the tensioned membranes （左）ETFE膜体布置图，(left) ETFE membrane （中）上层彩色膜体布置图，(middle) upper colored membrane （右）下层彩色膜体布置图，(right) lower colored membrane

The roof has three layers of stretched membranes, the middle transparent layer serves as the rain cover and the upper and lower layers as the sunshade. Three colors of the colored membrane echo three ones (pink, yellow and purple) of the flower sea. The selection of colors is another technical problem encountered in the design process. Several kinds of membranes reflect their bright color very well under normal light yet can turn into a gray color when is viewed from the floor in backlight. It proved that the coloration performance of mesh membranes in backlight was accurater than that of glossy ones. Mesh membranes were finally selected as a result. We ordered three special colors from the manufacturer which best echoed with the Natian Flower Sea.

▼彩色膜体细部，closer view of the colored membranes

观众席采用覆土的形式遮挡升起高度，使得衲田花海得以延续到观众身边。剧场成为纳田花海的组成部分，观众身处花海闻着花香观看舞台演出，表演者与观众、舞台与观众席的界限与关系得以改变。室外剧场这一古老的观演场所得到了重新的定义。

The raised height of the auditorium is covered by soil which can perfectly place the audiences into the Flower Sea, making our theatre a natural part of it. Audiences can thus enjoy the fragrance of flowers while watching the stage performance. Standing here, you will find the relationship between performers and audiences, the boundary between the stage and the auditorium all stay in harmony. In this way, the ancient concept of outdoor theaters has been redefined.

▼剧场位于自然之中，the theater was located in natural environment

▼覆土观众席与花田融合在一起，soil covered auditorium merged with the flower sea

▼剧场入口，entrance of the theater

▼剧场内看屋顶，view of the roof from inside the theater

▼夜景，night view

▼总平面图，site plan

▼一层平面图，first floor plan

▼二层平面图，second floor plan