Updating shape of extrusion object

[pri...@gmail.com]

How can I update the shape (and path) of an extrusion object with a slider?

The following simple example is far from perfect:

https://www.glowscript.org/#/user/priisdk/folder/My_Programs/program/extrusionslider

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]

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]

Can I then delete the compound and redraw it whenever the slider modifies the path and/or shape?

Poul Riis

[Bruce Sherwood]

Of course. Just make it invisible and create a new one.

Bruce

[pri...@gmail.com]

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]

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)