EMU is a form-finding tool implemented as a plugin to the parametric 3D modelling software Grasshopper3d. It was developed as a part of my M.Sc thesis in structural engineering. The question the thesis addresses is the feasibility of elastically bent gridshells in a Scandinavian context. Looking worldwide at realized gridshells and existing design methods, a gap has been identified between the required analysis process and existing available design tools. This has led to the pursuit of formulating a design and analysis process. Included in this has been to develop a codebase which can simulate the highly non-linear bending process with automatic supervision of the material capacity. The mechanics used is based on a six degree of freedom formulation of the Dynamic Relaxation method (6DoF DR). All equations and logics are compiled into a C# .NET class library which functions as an application programming interface (API). In order to achieve good code design which easily can be maintained and extended, the concepts of object oriented design patterns are used.


The structural output of the developed numerical framework is compared against analytical and physical models. Through four test cases the code is benchmarked and proven to be performing accurately. As a real-time structural analysis plug-in in a parametric environment, the user can easily interact with the model during run-time. Suggestions of how the developed tool fits into a bigger system of the gridshell design and analysis process are presented. The implementation of software design patterns makes EMU.dll straightforward to extend and modify to suit project specific needs.


The developed tool can be used in the structural design and analysis process of elastic gridshells. The combination of the underlying 6DoF DR engine and the implementation in GH makes EMU a novel tool with capabilities to interactively control structural models. Although the tool was written in the purpose of elastic gridshells, EMU can be used to perform various non-linear frame analysis including buckling, progressive collapse and form-finding.

Due to the 6DoF formulation used in EMU, bending moments about all three axes can be computed (including torsion).