Updating shape of extrusion object

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pri...@gmail.com

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Aug 8, 2022, 4:47:27 PM8/8/22
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How can I update the shape (and path) of an extrusion object with a slider?
The following simple example is far from perfect:

If possible, I would like to update the shape and path without the while loop in the same way as is possible with the length of the rod.


Poul Riis

Bruce Sherwood

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Aug 8, 2022, 5:24:48 PM8/8/22
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An extrusion is a compound and has the attributes of a box. It is not possible to change the path or shape.

Bruce

pri...@gmail.com

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Aug 8, 2022, 5:30:51 PM8/8/22
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Can I then delete the compound and redraw it whenever the slider modifies the path and/or shape?

Poul Riis

Bruce Sherwood

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Aug 8, 2022, 6:38:47 PM8/8/22
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Of course. Just make it invisible and create a new one.

Bruce

pri...@gmail.com

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Aug 9, 2022, 2:08:07 AM8/9/22
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But won't that will fill the memory with hundreds of objects?  Even if that may not be a problem I would find it better to delete old objects...

Poul Riis

mandag den 8. august 2022 kl. 23.24.48 UTC+2 skrev Bruce Sherwood:

Bruce Sherwood

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Aug 9, 2022, 1:05:02 PM8/9/22
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Oddly, no, it's really not a memory problem. When I run the program below and observe the memory usage, I find that 1e4 extrusions are created and then made invisible in 10 seconds with a memory rise of 1e9 bytes of CPU memory. That's 1e9/1e4/10 = 1e4 bytes per second, or only 10 kilobytes per second. It's fortunate that this is the case, since the documentation says this:

Deleting an Object

To hide a VPython object just make it invisible: ball.visible = False. This does not delete the object from computer memory, and you can make it visible again later.

Currently it is not possible to use del ball to delete a Web VPython object.

Web VPython 3.2
scene.range = 8
sphere(radius=0.5)
p = paths.rectangle(width=10, height=10)
s = shapes.rectangle(width=2, height=3)
t = clock()
n = 0
while True:
    rate(1000)
    ex = extrusion(path=p, shape=s)
    ex.visible = False
    n += 1
    if clock()-t > 10: break
print(n)
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