Advantages of the Grasshopper Interface
Grasshopper provides a suitable environment for developing the initial design concept. Through the visual scripting environment, parametric model design is feasible for users without programming knowledge. The direct visibility of the parametric model geometry also facilitates interdisciplinary evaluation and further development of the design. The parametrization of the geometry allows changes and variant consideration to be implemented with little effort.
With the help of the Dlubal plug-in for Grasshopper, the design model can be extended with an analysis model within the Grasshopper environment. This utilizes the existing parametrization for the structural model in RFEM 6. This link makes it possible to consider static aspects already in the early design phase and to directly derive the structural analysis and design for different model variants.
The following illustration aims to show a possible workflow between RFEM 6 and Grasshopper.
Subsequently, the implementation of individual areas of the workflow will be discussed in detail.
Parametric Geometry
The geometry is generated via Grasshopper components or an already existing model can serve as a basis. Lines and surfaces are required as geometry input for the components of the Dlubal plugin.
Dlubal Plugin
Dlubal-specific model and load data can be defined via various components and connected to the parametric Grasshopper geometry. The design model is thus extended to include an analysis model. The component structure follows the definition logic of RFEM 6. For example, the definition of a member requires a cross-section and a material.
Model Data
Model data adds properties for an analysis model to the parametrically defined geometry (e.g., material, cross-sections, members, hinges, supports, eccentricities, etc.). Properties that are selected from a list in RFEM can also be selected via value lists in Grasshopper.
Design Properties
The definition of design properties in Grasshopper is done only via the index numbers of the design properties. For this, information about, for example, buckling lengths, boundary conditions, and load-bearing capacity configurations is predefined in an RFEM template and controlled from Grasshopper. Creating a template is explained in the section Template for RFEM.
Load Data
With load data, the combinatorics (e.g., load cases, design situations, load combinations) and the loads (e.g., node, line, member, member set, surface, and volume loads) can be specified.
To define a load, a load case is always required in RFEM. For the definition of a load case, static analysis settings must be created and an action category for the classification of load cases must be specified. The necessary Grasshopper components for this are available. However, the complete load case classification and combinatorics can also be predefined in an RFEM template. In Grasshopper, only the load case number for the loads and the relevant load parameters are stored.
Template for RFEM 6
In an RFEM template (*.ft6 file), RFEM elements can be defined that are available in every new model created with this template. To do this, a model template must first be created in RFEM:
For design control, the required add-on is activated in the template, standards are set, and the corresponding design properties are defined, which are assigned via their index number in Grasshopper.
Object Selections
Object selections can also be defined in a template by filtering objects, for example, via a comment. If a comment is added in a Dlubal component, all objects with this comment appear in the predefined object selection.
Result Tables
The exported results from the "Export Results to Files" component always refer to the result tables in RFEM 6. In the result table manager, you can specify which results are exported with the component.
Printout Report
Required views as well as model and result documentation can be stored in the template via the printout report manager.
Export Settings
When exporting the model from Grasshopper to RFEM, an empty model file is first created in RFEM, and the data from Grasshopper is loaded into this model. If the storage path of a template file is stored in the export component (Use Template), the data from the template file is already loaded during the initialization of the new model, and the imported information from Grasshopper can reference it.
If the export is successful, the "RFEM 6 Calculate Component" automatically starts the calculation in RFEM. After the calculation is completed, the preset results of the calculation and design are saved into a CSV file. After saving the results, the printout report is also saved with the "Export Printout report" component in the specified storage path.
