Scott Davidson's Blog – May 2009 Archive (5)

Data Inheritance



Data is stored in parameters (either in Volatile or Persistent form) and used in components. When data is not stored in the permanent record set of a parameter, it must be inherited from elsewhere. Every parameter (except output parameters) defines where it gets its data from and most parameters are not very particular. You can plug a double parameter into an integer source and it will take care of the conversion. The plugin defines many conversion schemes but… Continue

Data matching is a problem without a clean solution. It occurs when a component has access to differently sized inputs. Imagine a component which creates line segments between points. It will have two input parameters which both supply point coordinates (Stream A and Stream B). It is irrelevant where these parameters collect their data from, a component cannot "see" beyond its in- and output parameters:

As you can see there are… Continue

How to set and alter persistent data records



Types of Data



Parameters are only used to store information, but most parameters can store two different kinds;



Volatile and Persistent data. Volatile data is inherited from one or more source parameters and is destroyed (i.e. recollected) whenever a new solution starts. Persistent data is data which has been specifically set by the user. Whenever a parameter is hooked up to a source object the… Continue

Definition Objects

A Definition can consist of many different kinds of objects, but in order to get started you only need to familiarize yourself with two of them:





Parameters contain data, meaning that they store stuff. Components contain actions, meaning that they do stuff. The following image shows some of the possible objects you are likely to encounter in a History Definition:…



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The Main Dialog

Once you have loaded the plugin, the _Grasshopper command will display the main Grasshopper window:

This interface contains a number of different elements, most of which will be very familiar to Rhino users:



1.The window title bar

2.The main menu bar

3.Component panels

4.The canvas toolbar

5.The canvas itself

6.The status bar

7.The remote control panel

8.Rhino… Continue