緣起
2012年7月10日Trimble SketchUp團隊受SketchUpBBS論壇的邀請，首度訪問中國上海、武漢、廣州三個城市，除了考察參訪以外，SketchUpBBS在三個城市各安排一場跟中國SketchUp使用者面對面的技術交流研討會。7月10日在上海外灘的遊艇俱樂部舉行的研討會，從下午13:30開始一直到晚上10:00結束。
SketchUpBBS一共準備了27個議題，含括了對SketchUp在各專業領域的應用，以及使用者對SketchUp未來走向BIM的看法與期待。筆者身為SketchUpBBS論壇的資深會員，特別為此提出對SketchUp的期望做為研討議題，議題的原文如後。
Expectation to SketchUp
By Paul Pai, Architect in Taiwan, SketchUpBBS Member: digitalarch (數碼阿叔)
● SUBIM = SketchUp + Plugins
I have been using SketchUp as our primary design tool for 10 years (since 2002). As an architect, I have been hoping the SketchUp team comes up with a Ruby plug-in that supplies comprehensive BIM functionalities.
我把SketchUp做為主要設計工具已達10年(始自2002年)。從一個建築師的角度，我希望SketchUp開發團隊能發展出Ruby外掛插件，賦予SketchUp完整的BIM功能。
〖說明〗
Despite of the fact that some people, due to unfamiliarity to SketchUp or other reasons, think SketchUp is only capable of conceptual design, many architects and designers like us have already been using SketchUp for the stage of schematic design and design development. With the help of LayOut of other CAD software, we can also produce construction document with SketchUp. In fact, SketchUp has always been the primary design tool, rather than just a sidekick.
In recent years, Building Information Modeling (BIM) is flourishing, forming a revolutionary wave in the architecture industry, and the China market will not be an exception. The China government is already on its way to settle down regulations for BIM implementation, and BIM may become a requirement in 2 years. With the raising of BIM, the BIM-based softwares will become the mainstream tools in the industry, and SketchUp can not be absent. We hope that the value of SketchUp can be extended to support BIM implementation.
However, it does not mean SketchUp needs to change its core functionality for BIM. We hope that SketchUp Pro can be enhanced to provide BIM functions via Ruby plug-ins, to keep the flexibility.
雖然有些建築業者、學者和軟體供應商，由於對SketchUp的功能一知半解或者基於其他目的，仍然堅持SketchUp僅能應用在建築概念設計(Conceptual Design)上。但是這些年來建築行業中的確有許多建築師和設計師不這麼認為，他們除了把SketchUp用在概念設計階段，還延伸到方案設計(Schematic Design)和深化設計(Design Development)階段，並且運用SketchUp搭配LayOut模組或其他CAD軟體，去完成建築施工圖說(Construction Document)。事實上SketchUp一直是許多建築設計工作者的主要設計工具(而不是製圖工具)
近年，建築資訊模型化(Building Information Modeling, BIM)在建築業界被炒得火熱，形成全球性的變革浪潮。當前中國的建築業界也無可避免的身處其中，推想在可預見的未來，基於BIM的建模軟體勢將成為建築行業的主流工具，政府正在制定BIM的實施標準，兩三年後可能會要求建築行業必須把BIM應用在工作中。我們不想SketchUp在這場變革中缺席，或者被摒除在主流設計工具之外，期待SketchUp的開發團隊能把SketchUp的功能擴展到BIM的領域，使我們能繼續把它應用在建築生命週期的各個階段。
全世界使用SketchUp的設計師數目可能超過了百萬以上，雖然其中大多數是在跟建築相關的專業領域裡，然而SketchUp是個面向多種設計專業的三維設計軟體，用在各種不同專業的設計師手中都是為人稱道的設計工具。因此我們認為不必為了BIM而更改SketchUp既有的核心程式，保持它與生俱來的高效率操作性，繼續讓SketchUp跟設計師的思維能同步運行比什麽都重要。我們的建議是強化SketchUp Pro版的功能，經由Ruby插件來賦予SketchUp完整的BIM功能，由使用者自己來決定怎麼有效的使用它。
● Building Information Modeling
In our interpretation, a BIM model satisfies the following two criteria:
1. It must be an object-oriented, three-dimensional representation of a building.
2. It must consist of some additional information about the objects beyond the graphical properties.
我們認知，所謂BIM模型需要具備下面二個特徵：
1. 它必須是一種基於物件導向、以三維表示的建築物。
2. 模型物件的屬性中必須包含圖形以外的特定建築資訊。
〖說明〗
SketchUp has leveraged the advantage of geometrical faces to the maximum. We can create a detailed skyscraper model in less than 100 kilobytes, as it only consists of the visual information of the building exterior.
However, when it comes to practical architecture design, there are three essential criteria to satisfy:
1. Architectural Object: These visual elements have to be grouped into architectural objects, such as predefined walls, windows, etc.
2. Data Association: Each object has to associate to its material and physical properties. For example, given a wall object, we need to keep track of its materials of construction, strength, weight, noise rate, heat transfer rate etc.
3. Calculation and Query: In the later stages of design, we have to do aggregated calculation and object query based on these properties. For instance, we may need to sum up the total volume of walls of a certain material, or to retrieve a list of objects that involve the use of a certain material in the model.
The challenge is, SketchUp model elements are not object based at the core. When we use push/pull function to generate a "wall", instead of a real wall object, it just creates 6 faces visually shaped like a wall. In addition, we also need to keep track of the physical properties of the wall, such as its materials of construction, strength, weight, noise rate, heat transfer rate etc.
With the current SketchUp. A possible way to work around is to support the object model via the use of Dynamic Component, and put the material information in Component attributes. However, with this approach, we will stuck at the stage that requires data manipulation.
We don't have a solid solution on how we can achieve the requirements yet. A wild guess could be handling the data externally by a 3rd party program, with Dynamic Component providing callbacks upon model changing and API for making changes back to SketchUp, so that the state of both sides can be synchronized via a plug-in as a bridge. In this way, SketchUp probably doesn't have to change much, while users can pick up their own backend BIM implementations.
SketchUp在三維模型上極致發揮了幾何面的效益，我們可以構建一座百米高樓的模型，看起來精緻得栩栩如生，卻只有一層薄薄的外殼表皮，內部空空如也。整個模型檔案的大小可能不到100 Kb，在Google Earth上你總會發現滿是這種型態的模型。否則如果拿那種動輒超過數百Mb的三維資訊模型栽在GE上，我不相信Google Earth還跑得動，更別說拿來利用3D模型做什麽GIS定位了。
但是在實際的建築設計應用中，需要構建的設計模型並非僅僅是一層薄薄的外殼表皮或者粗略的體塊。我們的模型包含了建築物內外部所有的建築構件，從樑、柱、牆體、樓板、屋頂、門窗、樓梯、欄杆…等等，甚至包含建築設備的細節，同時在模型的面(face)上也賦予了適當的表面紋理(texture)，通常我們不是僅只簡單的使用顏色(Color)，而是使用真實的材料紋理圖像(texture image)。
一向以來，經由SketchUp建立模型不是運用所謂"基於物件"(Object-based)的方式，也就是說在建模的過程中並非運用"牆"命令去創建一堵牆，或者運用"柱"命令去創建一根柱子。說得清楚一點，例如我們在SketchUp裡利用"Push/Pull"命令拉伸出一堵牆，實際這堵牆只是由6個面(Face)連接成"牆的形狀"，除了視覺上的主觀認知以外，在模型的數據庫(database)裡並不記錄或生成什麽跟這堵"牆"(Wall)相關聯的性質(properties)。即使你選取了這堵牆，你也無法得知牆體的構造材料、強度、重量、隔音率、熱傳透率和耐火時效等等特性。
原因是這堵牆的性質此刻並不是一個"物件"(Object)，可是當我們把它定義成動態組件(Dynamic Component)以後，它就具有了物件的性質。實際上當前那些所謂基於物件的件的BIM建模軟體所建立的模型構件(Model Elements)，骨子裡也都是些組件(Components)和組裝件(Assemblies)，利用相同的方式由程式建立，並附加了許多預設的屬性值和相應的編碼。我們可以從另一個角度來看，SketchUp的動態組件功能很大程度的能滿足這種需要，但是得預設一些必要的屬性欄位和內容，這些屬性值也就是這個模型構件所攜帶的建築資訊。在接下去的設計、施工以及使用階段中，我們適當的提取這些資訊，有效的用於設計、模擬(simulation)、分析(analysis)、乃至於估算、排程等等，這樣就能符合建築資訊模型化BIM的目的要求。
● Object-based Model Element
We hope, via plug-ins, we can create architectural objects (like wall, column, beam, slab, roof, window, door, etc.) directly in SketchUp, while assigning each model element a global unique object identifiers (OID) with a naming convention based on the classification given by UnitFormat II and MasterFormat.
我們期望，經由插件能在SketchUp裡直接建立"建築物件"(例如：牆體、柱、樑、樓板、屋頂、窗、門…等等)。對於Model Element賦予"全球唯一物件識別碼"(global unique object identifiers, OID)，並且參照AIA E202-2008 BIM Protocol Exhibit的要求，運用UniFomat II和MasterFormat對物件進行分類和命名。
● Query and List
It would be great if SketchUp provides a constraint query/listing function, so that user can retrieve target elements or aggregated values from the model. (For instance, the count of windows of a specific type, or the total area of building exterior tiles.)
建議SketchUp能提供查詢和輸出明細表的功能，使得使用者能從明細表進行計算和估價。
(例如：計算模型裡某型窗戶的數目，或者統計所有貼磁磚外牆的面積等等)
● Import / Export IFC file
As the members of consulting team may use different software, we hope SketchUp can supply import/export functionalities from/to IFC file format, so it would be easier to communicate with other software.
設計顧問團隊的成員可能使用不同的軟體，我們期望SketchUp提供導入和導出IFC格式的功能，以利於跟其他軟體進行溝通。
● LayOut
We hope we can insert Microsoft Excel file (perhaps .xlsx) into LayOut, in addition to Skp, image, plain text and RTF text.
對於LayOut模組，除了可以插入Skp模型、Raster Image、Plain Text和RTF Text等文件格式以外，我們建議能增加插入Excel表格(例如.xlsx試算表)的功能。
〖說明〗
The feature of Scene (Page) is one of the best features in SketchUp, regarding to BIM design. In many other BIM softwares, only a few fixed views are provided, so that users are forced to work on model from restricted viewpoints. Unlike those softwares, in SketchUp, user can freely decide the view, and freely orbit and zoom in/out the scenes. These scenes correspond to the drawing sheets in the old 2-dimensional CAD design methodology and serve as pivots to create different architectural documents. For example, to create a Construction Document, a SketchUp user would import the scenes into LayOut, set up print size, add a frame, legends, text comments, and eventually turns it into a formal document.
As LayOut can be used to create such documents, there is a common demand to enhance it to work with data tables and charts. Therefore we are also looking forward a possibility that LayOut can integrate with Excel.
往昔建築界應用二維CAD表達設計內容，不惟圖形數目很多，並且每個圖形(Drawing file)就只對應一張圖紙(Sheet)，個別製圖和改圖的過程中容易造成遺漏和各圖面內容不一致。
晚近，當所謂BIM建模軟體出現以後，在軟體供應商的一再宣傳下，眾多使用CAD的設計師驚喜的發現，BIM建模軟體在三維模型上預設了能對應平面、立面、剖面等等的各種"視圖"(View)，使用者可以從任一個視圖去修改模型，想當然爾其他視圖中顯示的內容也跟著改變。從這些視圖導出二維設計圖紙自然避免了圖形內容不一致的錯誤，減少了更改設計時的工作量，實際上也成為許多設計師改用 BIM建模軟體製圖的動機。
然而這種被說成史上初見的好功能，對於SketchUp的使用者來說，並沒有引起什麽刺激和興奮。因為"視景"(Scene / Page)頁面從多年前就始終是SketchUp固有的功能，每個設計師在工作中都會創建多個不同角度和觀視範圍的視景，並且在編輯過程中可以任意的環視(Orbit)和縮放(Zoom)操作視景。真正的三維設計軟體是能讓設計師按照自己的思維自由操控模型，而不是勉強自己去適應軟體程式設計者的操作想法，或者只能在固定比例的視景中工作。如果在應用三維設計過程中，設計師還是以傳統製圖習慣在平面視景上工作，那又何能算是三維設計呢？
SketchUp輸出二維圖紙(drawing sheet)的方式，和那些BIM建模軟體採用的方式有所不同，SketchUp並非從模型的視圖(View)直接輸出二維圖紙，而是透過LayOut模組操作。設計師完成精確的模型細節以後，從模型中把需要的"視景"(Scene)分別導入到LayOut裡，設定圖紙大小、加上圖框、尺寸標註、文字註解等等，最終輸出建築施工圖。
關於製作建築施工圖說(Construction Document)，除了應用到圖形、圖像和文字說明以外，設計師還會應用到各種表格和明細表類，諸如面積表、門窗清單、工程材料清單、估價表等等，因此很需要LayOut能具備插入Excel試算表的功能。
● "Partial" X-Ray Mode
We hope there is a "partial" X-Ray mode that transparentize only user-selected objects.
我們期望SketchUp的X光模式能針對使用者選取的物件顯示成透明或不透明。
〖說明〗
In the process of architecture design with BIM, it is often necessary to view only the objects of a certain types. In the X-ray mode of SketchUp, we can make all the faces semi-transparent, but there is no way to keep a group of objects opaque and the others transparent. It will be great if, perhaps in a new X-ray mode, user can select the objects he wants to keep opaque and show the texture, and leave others transparent.
開啟SketchUp既有的X光模式以後，模型中所有的表面(face)都顯示成半透明狀態，讓我們能透視到原先被表面遮蔽的模型內部，並且可以選取到位於內部的構件進行某些編輯。SketchUp的X光模式是全域性的，它無法只針對某些部份顯示成透明，換句話說，也無法讓某些部份維持原先顯現表面材質的不透明狀態。
當詳細的模型構建完成以後，有些模型構件會隱蔽在模型內部，例如被澆灌在混凝土樑柱內部的鋼筋，或者被封閉在管道井內部的管線等等。在實際應用中，我們有很大的機會需要把場景切換成可以透視到建築構件內部的狀態，方便經由視覺回饋檢查那些被遮蔽的物體，然而在SketchUp既有的X光模式下內外部都變成了透明狀態，反而不利於看清楚位於內部的物體。
因此我們需要增加一種新的X光模式，讓使用者能選擇那些部份顯示成透明(例如上圖中樑柱混凝土部份)，而其餘的部份(例如樑柱內部的鋼筋)維持不透明狀態，並且顯現出其表面材質。
● SketchUp can do more than visual representations.
SketchUp不僅僅用於視覺表現。
Model creator: digitalarch, SketchUpBBS member, 2008
● Our members have done more.
我們的會員已經做得更多。
Model creator: zfbim, SketchUpBBS member, 2009
Model creator: zfbim, SketchUpBBS member, 2009
● The Future:
• Visualization
• Integration
• Coordination
• Construction
• Maintenance
