Walls in Geometry Gym

A recent webinar about interoperability between Grasshopper and Revit make me look again on these tools, particularly for importing walls, In fact, I generally test these kinds of tools with a set a beams, more or less intricate, but never with walls, so I decide to generate a set of walls using the Geometry Gym IFC Importer for Revit.

Using Geometry Gym require at least some basic knowledge of the IFC structure. In fact, using this tool can be a really good starting point for studying the model behind Industry Foundation Classes.

Any IFC building object must be included in a (IFC) building, itself included in a (IFC) project, both of them must have a GUID and a name. So we start by placing these components on the Grasshopper’s caneva.

In order to have our NURBS path curve understood by Revit, we approximate it into a set of lines and arcs, using the specific Geometry Gym component.

We create an ggIFCElementParameter component to give a pretty name to our wall.

In order to create the multy-layer structure, we add two materials, both of them linked to a MaterialLayer component where we define the thickness of each layer. These component are merged into a MaterialLayerSet, itself link to a wall type.

The IFC class used by Revit for generating walls is the IFCWallStandardCase, so we use this component in our Grasshopper definition. We link all these components to our IFC Wall Standard Case, had a height parameter, and bake the whole think.

The resulting IFC file contains a pretty good wall, with every expected parameter. We check it in my favorite IFC viewer, the Solibri Model checker.

Once imported in Revit, using the embedded plugin, it creates a generic component looking like our wall. It appears in a schedule with the family name and type as set, but it’s still not an editable Revit wall.

I generally use the massing tool to create walls in Geometry Gym. I create a simple IFCExtrudedAreaSolid (for example) from a base NURBS curve, and then import it in Revit to generate a mass.

 

I can now use this mass to create my curved walls in Revit, along with the floors slabs. This method need an additional step (creating the wall from the Revit mass faces), but create native Revit walls.

As I write these lines, a new version of the IFC Import plugin for Revit have been posted on the Geometry Gym blog, I still have to review the improvement.

From Grasshopper to Tekla

I keep on trying the Grasshopper Plugin Geometry Gym, and one of our current projects made me search more extensively in the Tekla export module.

It presents itself as a set of tools to create beams, plates, bolts and welds. There is also a TeklaBakeStructure component to send our Grasshopper geometry to Tekla.

Creating beams is pretty easy, all you need is a BeamProfileProperty before, where you set all Tekla parameters of your expected beam. Then you just link your wireframe lines to the beam component.

I struggled for a while to set the Insertion Point property in order to set the position of the beam axis before realizing that I only had to right-click on the parameter to set it. I finally extracted it to keep it visible.

The plate component is also quite simple, with a polyline as input and more or less the same set of property as for beams.

To link two parts together, and so create a Tekla assembly, you have to create a group of bolts (or a weld), then assign it to the main part with the specific input, and add to the assembly all secondary parts you need. I am not sure if it is realistic to create assembly for a whole project directly in Grasshopper, but maybe I am missing some point here. My current project involves a lot of connexions, so I will keep on exploring these features.

 

To exploit a model imported in Rhino, Jon Mirchtin has developed two specific components call Reverse Engineer. You can use it to retrieve beams or plates properties from geometry. Here is an example of a plate recreated from a standard Rhino Closed PolySurface.

Once all you profiles and other parts are created into Grasshopper, you can export them. Just run Tekla, start a new project, and click on the TeklaBakeStructure component on your Grasshopper canvas.

Your model is now export in your Tekla project.

This plug in fill one of the most lack in the Tekla functionalities, the ability to create complex shape quickly. With this module, it became pretty easy to adapt a lot of beam on a double-curved roof, and create them in Tekla.

Geometry Gym

I was talking on a previous article about the Grasshopper plugin develop by Jon Mirtschin called Geometry Gym.

This set of tool for building modeling firstly came as a plugin for Rhino, implementing commands for designing structures and linking these models to structural analysis software.

These tools where integrated as commands in Grasshopper, allowing generating building elements parametrically, a very interesting feature at an early stage of the project.

But for me, the most interesting part of this plugin is its ability to generate IFC files into Grasshopper. A large part of the IFC classes are implemented directly as Grasshopper functions.

By combining these functions, we generate the structure of our IFC file exactly as we want it, and if our favorite BIM software is known for missing some IFC classes, we can still use a workaround by designing yourself your IFC data structure.

Using this plugin requires a little understanding of the IFC data structure, but examples can be found on the Geometry Gym blog, and are quite self-explaining.

Combined with the building modeling tools described above, it provides a powerful way of designing building, especially at the early stage of the project.

Geometry Gym came also with various plugins used as bridges for other BIM software

The plugin for Revit implement a new IFC Import module, especially design to import files generated in Grasshopper. This allows integrating native Revit element from an IFC file.

There is also a direct link with Tekla, use to generate native Tekla elements directly from the Grasshopper model.

If this software need some time to get used to it, and a little knowledge about the IFC Data structure, once taken in hand, it become powerful enough for replace any conventional BIM software, at least at the beginning of a project, and especially for complex shapes and structures.