外裝型氣罩的捕集功能深受多種因素的影響。根據以往研究顯示，氣罩所產生的吸氣氣流在側風下會形成一捕集區，在捕集區內的有害物較易被氣罩捕集，在捕集區外的有害物則較有可能隨側風脫逃。國內有關捕集區的研究已進行多年，本計畫整合以往研究，並以一既有程式為基礎開發一能以動畫顯示氣罩於側風中捕集空氣中粒子的模擬程式，程式名稱為HOODCAPTURE。除了使用投影技巧外，HOODCAPTURE 程式使用兩個動態配置的二維矩陣以及一個動態配置的陣列儲存所需的數據。兩個矩陣分別儲存模擬畫面每一個像素的粒子數與背景色彩，陣列則用來儲存每一模擬粒子的三維座標位置、速度向量以及粒子狀態。程式除能以動態模擬捕集狀況外，尚可顯示捕集區範圍並計算捕集效率。HOODCAPTURE 程式整體而言已能順暢執行各種模擬狀況，且對系統資源的使用也具有相當效率，此程式有助於未來對捕集區問題更進一步研究，也有助於教學的進行。

The capture performance of an exterior hood used in a local exhaust device may be affected significantly by air flow from other source. According to previous theoretical and experimental studies, the combination of the exhaust flow generted by an exhaust hood and a cross draft will form a capture envelope in the flow field. All streamlines inside the envelope are lead to the exhaust opening,those outside the envelope are lead to the infinite downstream of the cross draft. This study compiled the results from those studies, and developed a computer program to simulate how an exterior hood capture the air-borne particles under a cross draft in animation. This program was named as HOODCAPTURE.HOODCAPTURE program was developed According to an old version program which can only show capture in a static manner. Two dynamically allocated matrixes were used to store the particle number and background color of each pixel in the simulation window respectively. A dynamically allocated array was used to store the position, velocity components and status of each particle. In addition to capture simulation, the new program will show the range of the capture envelope and compute the capture efficiency.This program run smoothly under every simulation condition, and consumed system resources in an efficient manner. It is helpful for further studies to capture velope, and also useful in education use.