Ramp Easy
Introduction
Expected Time: 30 min
In this tutorial you will learn how to create a ramp, based on a curve. This ramp will have no plateaus, if you do want them, take a look at Tutorial 13 - Ramp Intermediate Of course, you can combine this tutorial with Tutorial 3 - Railing. This will be explained in the final chapter. Before we start building the ramp however, this tutorial will have an intermezzo explaining planes in Grasshopper.
The Design
The design of the ramp will consist of the following parameters:
- A Rhino curve/the shape of the ramp
- The shape of the ramp section
- Standard railing parameters, as can be seen in Tutorial 3 - Railing
Intermezzo - Planes in Grasshopper
As you may have noticed in the previous tutorials, geometries have always been created using X, Y and Z values. These X, Y and Z values tell us something about the location and size of the object in 3D space. Sometimes however, it is useful not to use the standard coordinate system of Rhino, but to create a plane and define what the X, Y and Z directions are yourself.
In this intermezzo, you will learn some methods to create a plane.
2D Plane
2D planes are based on an origin point. For example, by using an XZ plane, the original Z direction in Rhino becomes Y in the new plane. You can use this plane to create a rectangle. The origin input is the point where the plane is created.
- The XY, XZ and YZ Plane can be found under
Construct Plane
You can also create a plane yourself, based on an origin point, X-axis and Y-axis. This can be useful when you want to create a 2D or 3D object in a specific direction without rotating it manually.
- The Construct Plane can be found under
Plane Normal
A plane normal is based on an origin and the normal direction, otherwise known as the direction perpendicular to the plane.
- The Plane Normal can be found under
Curve Planes
Multiple planes based on a curve division. Generally speaking there are two functions to do this: horizontal planes and perpendicular planes.
- Curve divisions by planes can be found under
Step 1 - Creating the Ramp
First we create a curve in Rhino that is the basis of our ramp. In this example we used the spiral function. Next this curve should be set on a curve parameter in Grasshopper.
- Create a curve in Rhino, for example
- Set the curve to a curve parameter
Now we need to create a section through the curve for the final ramp. An easy method to do this is using horizontal frames.
- Divide the curve by horizontal frames
- Add a number slider to the count, 50 would be a good start
As you can see, we have one problem now. The sections should be created in the perpendicular direction from the curve, which is not possible with this two-dimensional plane. Therefore we need to deconstruct the current planes. After that, using the new axes, we create new perpendicular planes.
- Deconstruct the created Frames
- Create a new plane (Y becomes X, Z becomes Y)
Create a section of the ramp on each frame with a rectangle. You can set the X Size and the Y Size with a construct Domain function, as we have done in previous exercises. For the domain start we add a negative function, so that the rectangles is created in two directions.
- Connect the Plane output with a rectangle
- Add a Construct Domain function to the X Size and Y Size
- Before connecting a Number Slider, add a negative function to the Domain Start
The ramp can be created by lofting the sections.
- Loft the rectangles
As you can see, the ends of the loft are not closed. This can be fixed by adding the cap function
- Cap the loft
The ramp is now finished. Set off the preview of all nodes and add a final geometry parameter.
- Set off the preview of all nodes
- Finish the script with a geometry parameter
Step 2 - Adding the Railing
Now that we have finished the main part of the ramp, Tutorial 3 - Railing tutorial can be used to create a railing. However, the input of this script is a curve, so we need to select which curves we will be using for the model.
First we should deconstruct the ramp in faces, edges and vertices with the Deconstruct Brep function.
- Deconstruct Brep output
Now we use list item to select the edges we need. Probably you should use numbers 9 and 10.
- Select the correct edges with a List Item
- Connect a panel to the Index and type 9 (Enter) 10
Your script will probably not work because your panel is not set right. By right-clicking on the panel and selecting Multiline Data, you can solve the problem.
- Set the panel to multiline data
As you see in the left picture, we now have the two curves we need for the railing.
Although you might think the script will work like this, we still need to graft the output. We have been talking about grafting before, but it is still hard to explain at this moment. Think about it like this: you want the curves to be handled individually and not as group. Of course we could add a graft node, but a cleaner way to do this is by right clicking on the Item output and select graft.
- Graft the resulting curves
Finally, you can import the railing script created before. The tutorial can be found on Tutorial 3 - Railing Just connect the output of the List Item with the curve input of the railing script. This may look like the image on the left.
- Copy your railing script to the ramp script
- Connect the List Item output with the curve input of the railing script
By selecting the ramp geometry parameter and the railing geometry parameter, you will see the full ramp.
