用竹片彎曲做設計-自然材料與數位設計之結合

Abstract

本研究的動機來自於一實際竹構築的案例，思考如何用剖竹片的自然彎曲形態做設計，然而在設計過程中所遇到最大的問題是竹片彎曲曲線無法在3D環境被定義或描繪。由於自然材料其中一大特色是非均值性，使它在外力下產生的形態不平整而難以預測其形態，造成後續的空間檢視和結構分析等沒有評估的依據。別於傳統的定義幾何形體的設計方法，案例中的設計方法是以材料行為為誘發因子產生形態，這樣的設計方法需要材料屬性和行為分析以及數位工具的可運算能力做輔助。

由於材料特性，一般而言自然材料搭配的是可以與材料即時互動的工藝生產技術，來面對不均值以及不規格化的材料特性。而數位系統對材料資訊的訴求是可靠性和一致性的資訊交換，需要的是精準的材料資訊。因此，如果沒有一個模型來描述竹片彎曲行為，材料資訊以及所做的材料試驗結果無法直接置入數位設計系統中運算和使用。

為了要連接這兩者間的斷層，本研究透過竹片彎曲試驗、竹片彎曲行為參數模、建築形體生成和材料建議與組裝四部分展示了如何將自然材料和數位設計結合。透過一系列的材料試驗和參數模搭配、分析竹片彎曲行為、整理影響竹節彎曲形態的變數、歸納出彎曲特性以及將這些資訊建成資料庫。最後提出一個竹片設計工具，可設計出具有竹片彎曲行為的形體，並藉由資料庫達到形體預測和材料準備建議的目標。

最後，用數位系統不僅承載了工藝師對材料的知識，也改變了自然材料搭配的傳統工藝技術生產方式，降低傳統工藝技術的施工門檻和各階段的斷層。除此之外，竹材特性和資訊傳遞在數位系統中自動化的過程中，創造了自然材料發揮更大的特性的機會，不再只是幾何形態導向設計的附屬品，這使得我們有了更高的進行創新的數位構築的可能性。

This research was motivated by a built bamboo pavilion, of which the intent was focus on how to design with the natural forming by the bamboo strips when bent. However, the biggest problem encountered during the design process was the bend curve couldn’t be defined or described in 3D environment. Due to a significant characteristic of natural material, heterogeneity, the form created by force is irregular and hard to predict. Subsequently, spatial review and structural analysis couldn’t be evaluated. Unlike conventional geometric-defined design approach, the form of the built bamboo pavilion is generated by material behavior, this kind of design approach should be based on the material properties and material behavior analysis, and should be aided by the computability of digital design tool.

In order to deal with the heterogeneity and the irregularity, generally, natural material is coupled with crafting techniques, which has instant interaction between material the maker. However, the demand of digital system is reliability and consistency of information exchange, precise material data is needed. Therefore, without a model to describe bamboo strips bend behavior, material data and material study results couldn’t be inserted into the digital system for design usage.

This research demonstrated how to bridge the gap between natural material and digital system by 4 parts: bamboo strips bend experiments, bamboo strips bend parametric model, form generator and assembly from material suggestion. A database is constructed based on the parametric model which combined with material experiments, bamboo strips bend behavior analysis, bend form variables and bamboo strips bend characteristics. Additionally, a bamboo strips design tool is proposed, to generate behavior-driven form, and to achieve the goal of form prediction and material suggestion from the database.

As a result, digital system not only carries material knowledge that craftsmen obtain by experiences, but also shifts the way that natural material generally coupled with crafting techniques. The shift reduces construction techniques level and bridges the gaps between stages of crafting techniques. Furthermore, bamboo strips characteristics and data exchange in the process of automation in the digital system, has created an opportunity for better elaboration of material, which no longer just a by-product of geometry-centric design approach. Finally, we may pursue innovative digital crafting with significant potentials.