上回提到BIM的應用令一眾工程設計人員可以不用繪圖，其實有點語言偽術，因為這樣說忽略了重要的一點：原始BIM的模型也要一磚一瓦的建立。你問 我，建立BIM模型不能說不花時間，設計時要同時兼顧模型和資訊的輸入，也比CAD要多功夫。那問題又來了，為甚麼要花這時間？ 我常和學員說，BIM是一個「先苦後甜」的程序，換句話說設計初期要投放的心機時間的確較多，甚至表面上比CAD繪圖要慢一點，但當BIM模型漸見雛形，你就享受到他帶給你的協同效益，其中之一是我們做任何設計改動都會更易，因為你改動的是模型，但相關的圖紙及數據電腦已助你同步更新。
那麼如果用 CAD是「先甜」 (草草幾條線就可有一設計圖) 「後苦」 (改動較多手動跟進)，看似是打個和，那BIM來幹甚麼？其實答案很簡單，我們做設計，是要來「搵食」的，世上任何商業行動，都是有時限 (Deadline)的，如果我們還在deadline臨近之際還讓一個緊急的設計改動伴隨沒完沒了的文件修正，你一定會敗給一個在早期勤勞，但後來可輕鬆應對改變的BIM。
可能你已認為只用BIM作為一個設計表達工具，已是莫大的改善，其實這還未發揮BIM的真正益處，就像超級跑車在香港的公路悶行一樣。BIM的最大 益處，是分析。現代建築已有很多問題會先模擬一下，在建造前先找出問題及解決方案，免得起好才後悔。例如很多人都知香港的高樓大廈要在風洞模擬測試是否抗風，以前要做一次風洞測試所費不菲，既要建實體模型又要比實驗室費用。現在有了BIM模型，不但準確，還附有所需資訊，在風力模擬的軟件虛擬的測一下，詳 細結果立即出來，還有你的設計不斷改，分析數據也是同步更新的，你說這慳了多少？設計精準了多少？所以如果你希望或正在以BIM為你的專業路向，請不要忽略分析這一大片高價值的領域。
Last time, I was being tricky to say that you “do not need to draw your design anymore”. The statement neglected one fact, i.e. you still have to create original BIM models step by step. You may ask, “Building BIM takes time, and the word load can be much heavier than CAD, while you have to take care of the models and information simultaneously, then why do we bother to spend those time for BIM?”
I often tell my students that BIM is a “pleasure comes through toil”, in other words, you will be spending more time and effort in the initial design, and most probably the workflow will be slower than CAD, but when the model is gradually taking shape, you will enjoy the synergy it brings you. One of the advantage of BIM is that you will find design revise very easy since when you adjust the model, all relevant drawings and data will be updated correspondingly. If you find CAD a pleasure to complete the drawing with lines, then the toil come when you will have to make a lot of changes manually afterwards. You may still say that “it sounds like that the comparison of BIM and CAD workflow is a draw game, then why should we go BIM? ” The answer is simple and clean, we make a living with design, and there is always a deadline in every commercial activities. If we want to give yourself crazy adjustment workload revising designs, you won’t be able to compete with somebody who is willing to work hard on the initial stage and make them very flexible to cope with changes.
You may consider BIM as a big improvement in design expression, however, this design workflow has not played the real benefit of BIM, which is like supercars that are stuck in Hong Kong’s highway. The largest benefit of BIM, in fact, is analysis. There can be many problems in modern architectures, that you want to simulate and find out solutions and alternatives before construction. For example, many people want to know buildings in Hong Kong has to go through wind tunnel test in order to know the wind resistant data, but the price of the test is very expensive, which cost include the construction of solid model and experiments. Now with BIM, with high accuracy, you can obtain all the data you need with virtual wind simulation, and the data updates as you make new adjustments to your model. In this case, you can tell how much money you have saved, and how much more accurate is your design. Therefore if you wish to develop your career with BIM, please do not neglect “analysis”, since it is the most valuable area of the technology.
Joshua@The Outstanders, Trainer in creative training, rambles on construcions, design, culture and lifestyle.