Here's an example of what the final model does when interacting with the parametric sliders.
I will now go through screen shots of grasshopper and rhino to show you what I did to create the model. Click the link or go to the bottom of the post to watch a video going over the process.
Santiago Calatrava's TGV Station in Grasshopper
As you can see, the only components visible in rhino are control points I used to create nurbs curves that mimicked the skeleton of the model.
The scale sliders use the control points of these basic nurbs curves to control the scale of the form hence the multitude of inputs into the nurbs curve node. From these nurbs curves, I was able to begin creating the basic form of the model. I began with the outer wings I couldn't simply create a loft between corresponding nurbs curves because they both began and ended at the ground plane, while the model shows a surface that begins at the ground and ends about two-thirds the distance of the imaginary curve. To do this, I divided the corresponding curves by a number parametrically controlled by the structure slider. I then selected certain points using the list item node as well as the split list node. These points created the skeleton of the final lofted surface for the outer wings. In addition to this, I also created the structure needed for piping offset from the surface as well as create the beginning of the vertical structure using a series of divide and split list nodes.
As I stated before the beginnings of the vertical structure were created int he previous "outer wing group." I simply projected lines created by find the midpoints of the before mentioned lofts. Only this time, the portion of these lines were selected to project down to the base tunnel surface because in the model, there is an are without vertical structure in both the front and back of the model.
The next step was to create the inner wings. What made it difficult to create these wings were that they also contained skylights. To do this, I created a lofted surface between corresponding lines much like mentioned before, but used the sub-surf node to divide the surface and explode and extract the vertices I then used these vertices and through the use of various list item nodes, I was able to create paths that resembled that of the TGV's skylights. I finally used the surface split node to split the surface at the paths and used the cull node to delete the unwanted surfaces.
Finally, I used the pipes node to visualize the structure much like the TGV used and joined all of my lofts to create a easily bake able final product.
Santiago Calatrava's TGV Station in Grasshopper
