Transformations grasshopper
Introduction
The tools for transformation in Grasshopper are quite similar to the tools in Rhino In Grasshopper however you need to define every component of the translation. This can make the process quite time consuming, however once the transformation is set up correctly the adjustments can be done very fast. The options for transformation can be found on the Transformation tab
Move
Move geometry input
To move an object in Grasshopper we first need to select an object to move and the move component. If you use existing geometry from Rhino the geometry is already defined. That means that you can define that geometry as a Parameter. It might be necessary to cut a part of the design if the part which you want to move is connected to another object. You can connect it again once the final design is established.
If the geometry is a surface the Brep parameter is used.
If the geometry is a curve made in Rhino then the Curve parameter van be used.
If the geometry is a set of points made in Rhino or Grasshopper then the Point parameter
Vector
A Vector describes a direction and distance. Vectors are widely used in Grasshopper and form often the basis for complex transformations. The vector can be defined in three ways.
- A Unit vector. This is a vector in the X, Y or Z direction. The standard distance is set to 1. If you want to increase the distance you add a number slider to the Unit vector component.
- A point can also work as a transformation vector. This point can be created or an existing point can be used. If the point has the coordinates of X=2, Y=4 and Z=6 and it is used as a move vector the object will move 2 units in X direction, 4 units in Y direction and 6 units in Z direction.
- If you have two points then you can use these points to define a vector
Rotate
There are several option for rotating an object. We will focus on two options. The Rotate around an axis and the Rotate 3D option. Both are similar to the options of rotation which we use in Rhino. And in both cases we need to define the geometry to rotate and a rotational axis. The difference between both options is that the rotate around axis uses a line as an axis. The 3D rotate option uses a point and a vector. The point defines the location of the axis and the vector will define the orientation of the axis. It does therefore exactly the same as the previous option only the inputs are different. This is something you will often see in Grasshopper.
- Rotation around axis. This option needs an rotation axis which can be defined in Rhino as a curve and then defined in Grasshopper as a parameter. The other option is to extract an edge from a surface and use that as a rotational axis. In this case we only will focus on the definition of the axis in Rhino. And of course we need the amount of rotation. This is defined in Radians. There is a component which makes it possible to convert degrees to radians. It can be found in the Math tab- Trig - Radians
- 3D rotate. This option is the same as the previous one, with one major difference. The rotation axis is defined by a point of rotation and a vector as orientation of the axis.
Scale
The scale options are quite straight forward. There are two main options. A uniform scale option and a non uniform scale option.
- Uniform scale option. This option requires only the geometry input and a reference point for defining the center of scaling and of course the scale factor. The center point can be defined by using the point parameter.We can use a slider for the scale factor.
- Non Uniform scale option. In this case we can define the direction of scaling. This x,y or z direction is coupled to its construction plane, the grid. If you want to use the standard grid / construction plane then leave the settings as they are. The settings for the construction plane can be altered at Vector - Plane. here you will find several options of defining the direction of the construction plane.
The Construction plane can also be defined as a Parameter. That allows you to define the construction plane in your scene.
