CUI為新加坡BCA Green Mark計算永續發展的指標之一，但未提供二氧化碳等溫室氣體的資料，而BEES提供材料計算，但不考慮設計合不合理，本研究希望整合兩者優點，製作同時考慮CUI與BEES的永續整合指標計算系統。
為了同時計算CUI和BEES，本研究選擇在Revit上做功能擴充，Revit支援add-in功能，使用者可以自由加入功能元素，原本計算CUI值的部分，採用bounding box的計算方式，加總牆壁，地板，天花板等元件的體積後，除上可用地面積，也就是地板的加總，這樣就能計算出建築物的CUI值。
之後是BEES的計算，先在BEES網站取得各種混凝土資料，再和Revit CUI add-in 做結合，BEES的資料儲存格式是Excel，資料轉換過程使用了Excel macro，Excel macro 使用VBA以執行巨集的方式運作。而所謂的巨集就是使用 Visual Basic 語言撰寫之循序漸進的步驟流程，在 Excel 中使用 VBA 最常見的原因就是為了自動化重複性的工作，本研究的BEES資料共有24種混凝土，每種混凝土有26筆屬性和4筆小計。為了快速把BEES資料轉換為Revit 所接受的C#格式，所以本研究的資料轉換過程使用了Excel macro，然後和CUI的程式結合，製作出結合CUI與BEES兩者的永續整合指標計算系統。

CUI (Concrete Usage Index), one of the most important Singapore BCA (Building & Construction Authority) Green Mark sustainability indexes, has been extensively utilized in construction projects and is calculated in accordance with building geometry. However, it does not shed light on the information regarding how much greenhouse gas, like carbon dioxide, methane, is generated for a given construction project in analysis, which can be determined by using BEES (Building for Environmental and Economic Sustainability), developed by U.S. NIST (National Institute of Standards and Technology). Nevertheless, the information presented by BEES is not related to building geometry, which implies that an architect cannot adjust the building’s geometry in order to find out the optimal design regarding the environmental impact. This research aimed at combining the benefits of both CUI and BEES and at creating an integrated sustainable index calculation system. The system can automatically retrieve a building’s geometry data from a Revit file and perform the CUI calculation task. It will then synthesize the BEES output data to show how much greenhouse gas generated for a given BIM model. To calculate CUI, a Revit add-in was created. Then, several EXCEL macros were crafted to collect data from BEES and to combine them with the CUI add-in. A total of 24 cement types from BEES, each holding 26 attributes and 4 subtotals, was compiled into the CUI codes, in order to show the amount of greenhouse gas for a project. The system should be able to assist architects as well as construction managers in estimation of greenhouse gas impact in accordance with a BIM model automatically, which may expedite the design cycle to quickly find out the best design from the perspective of environmental impact.

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