This guide discusses different techniques of loading and running script and their efficiencies.

## LoadScript and RunScript

When running a script from a toolbar button, is it better to use the LoadScript command or RunScript command? Which is better for Rhino, resource wise?

1. Opens the script file, reads the contents of the file into a buffer, and then closes the file.
2. Loads the buffer, read in from the script file, it into the scripting engine. The script engine, then, attempts to parse the script.
3. If the script was parsed successfully, it is run, or executed.

The RunScript command:

1. Runs the script, skipping steps 1. and 2. listed above.

## Considerations

Using LoadScript to load the same script file over and over and over again is somewhat inefficient and certainly unnecessary, as you are simply replacing the same script, over and over again, that is already resident in the script engine. The only time you need reload a script is if the script has changed, or if the script engine was reset.

One technique you can use to be more efficient, when loading scripts, is to have them load at startup. You can specify the scripts to load at startup by selecting Tool > Option > RhinoScript. Then, you can just use the RunScript to execute your pre-loaded scripts.

Another technique you can use it to load your scripts on demand. For example, say you have a Hello.rvb script file with a single function defined as such:

Sub Hello
Call MsgBox("Hello Rhino!")
End Sub


From a toolbar button, you could use the following macro to load it on demand and then run it:

_-NoEcho _-RunScript (
If Not Rhino.IsProcedure("Hello") Then
Call Rhino.Command("_-LoadScript Hello.rvb", 0)
End If
Call Hello


The code above checks for the existence of a user-defined procedure (e.g. subroutine or function) named "Hello". If the procedure is not found, then script file, were the procedure is stored, is loaded by running the LoadScript command. Finally, the specified procedure is called.

To ensure this technique works, make sure to included the path to Hello.rvb is included in Rhino’s file search path by selecting Tools > Options > Files.