Re: [Visualpython-users] deleting scenes

[Guy K. K. <g....@ma...>]

On Mon, 29 Jun 2009 11:28:22 Bruce Sherwood wrote:
> Here's what I've put into the documentation at vpython.org (and will go
> into the documentation that is installed locally for Visual):
>
>
> To hide a Visual object just make it invisible: ball.visible = 0. This does
> not delete the object from computer memory, and you can make it visible
> again later.
>
> If however you later re-use the name ball, for example by creating a new
> object and naming it ball, Python will be free to release the memory used
> by the object formerly named ball (assuming no other names currently refer
> to that object). If the object is visible when you re-use the name ball,
> the original object will not be deleted from computer memory, and it will
> remain visible in the window.
>
> Suggestions for improvement?

You might want to add something how to explicitly delete items as well. E. g. 
to remove them *now* call "del foobar" after setting the object to 
"obj.visible = False".

BTW, I'd also suggest to use "ball.visible = False" rather than "... = 0". The 
boolean nature is much more expressive, and it also implies that you don't 
have a "value" there, which could be interpreted as visible = 0.5 is like 
opacity and makes it only half visible. This change would remove ambiguity 
straight off the bat.

Guy

-- 
Guy K. Kloss
Institute of Information and Mathematical Sciences
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