visualpython-users

Re: [Visualpython-users] Do Vpython have good future?

[Arthur <aj...@ix...>]

Good question.

I think VPython is wonderful.  And could have a great future.

If its potential  beyond physics currciulum visualization were actively
pursued and better considered and promoted.

Unfortunately its seems to have found itself cornered in a situation were
those who have undertaken responsibility for it have only that one narrow
interest in it.

Art

Re: [Visualpython-users] Do Vpython have good future?

[Bruce S. <bas...@un...>]

Some context and history may be helpful. The creator of Visual, David
Scherer, left college early to take advantage of an unusual business
opportunity. That left Ruth Chabay and me as custodians of the project, but
during the last year and a half or so we were pretty consumed with a major
move from Carnegie Mellon University to North Carolina State University and
were unable to exploit a grant from the National Science Foundation to push
VPython in new and broader directions. Also, our major responsibilities are
not VPython, so any enhancements or maintenance we were able to undertake
were necessarily aimed for the most part at supporting our physics education
work, though much of this work has been of wider benefit. We finally have
our feet on the ground at our new institution and plan to use the NSF grant
resoursces to hire a strong full-time programmer to begin to address wider
interests and needs of current and potential research and educational users.

Also, Scherer has some interesting ideas on a longer-range restructuring of
the Visual module to make it an open-source project in fact as well as in
principle. Scherer's original implementation in C++ got VPython running
amazingly quickly, with excellent capabilities, execution speed, and
stability. However, the code is rather complex, which has meant in practice
that no one other than Scherer has felt competent to make major changes to
the core of Visual. Mind you, no one is preventing anyone from changing
Visual to suit their own needs, since Visual is an open source project
housed at sourceforge.net. But the benefits of open source may not be fully
realizable if the source looks too difficult for newcomers to modify.

Scherer believes that it could be possible to rewrite Visual with a
radically different architecture which would have the goal of making it
feasible for many people to be able to contribute to its further
development, once the new architecture is in place. A related goal is to
make the basic graphics capabilities sufficiently "professional" to attract
the interest and inputs of those people who are very knowledgeable in
computer graphics. No one is currently working on such a new architecture,
but Scherer's vision is important, because if the project were truly
modifable by many people it could more easily and quickly grow or be
customized to address diverse needs and interests. And if it were made
interesting to graphics experts that too would stimulate interesting further
development.

Bruce Sherwood

----- Original Message -----
From: "Arthur" <aj...@ix...>
To: <vis...@li...>
Sent: Sunday, December 29, 2002 8:54 AM
Subject: Re: [Visualpython-users] Do Vpython have good future?


> Good question.
>
> I think VPython is wonderful.  And could have a great future.
>
> If its potential  beyond physics currciulum visualization were actively
> pursued and better considered and promoted.
>
> Unfortunately its seems to have found itself cornered in a situation were
> those who have undertaken responsibility for it have only that one narrow
> interest in it.
>
> Art

----- Original Message -----
From: "zhang xianying" <th...@ya...>
To: <vis...@li...>
Sent: Sunday, December 29, 2002 7:23 AM
Subject: [Visualpython-users] Do Vpython have good future?


> Hello!
>
> I find out this list is very dull.Do Vpython have future?
>
> I hope get your response.
>
> Thanks!
>
> Zhang xianying

Re: [Visualpython-users] Do Vpython have good future?

[Gary P. <pa...@in...>]

> Some context and history may be helpful. The creator of Visual, David
> Scherer, left college early to take advantage of an unusual business

Thanks for the note, Bruce.

I'm a VPython newbie, and a physicist, not a programmer, and I'm finding
VPython intriguing.  My interest is primarily for demos and simulations.
What programing I do I do in Python, so VPython is potentially perfect.  I
check for submission to this list daily, and I'm sure I'll contribute as I
get to know it better.   I for one appreciate the effort being done.  I've
had a vague understanding that resouce issues have slowed maintenance and
development.  I think think visual fills an important need in python, and I
look forward to its healthy future.

-gary

[Visualpython-users] controlling zooming

[jon s. <js...@so...>]

(Happy New Year!)

This program builds blocks out into space correctly, but it automatically
"zooms" way out (too far out) about midway through.

I can't figure out how to control this.

When I fiddle with scene.range, the image gets dim as if the lights have
been turned down.

I'd appreciate any ideas.


from visual import *
from time import sleep

pause=.2

c=[]
def init():
	for i in range(10):
		c.append((0,0,0))

	c[0]=[255,255,255]
	c[1]=[255,153,51]
	c[2]=[102,102,153]
	c[3]=[255,0,102]
	c[4]=[102,102,153]
	c[5]=[255,102,0]
	c[6]=[128,0,128]
	c[7]=[255,255,0]
	c[8]=[51,51,153]
	c[9]=[255,0,102]
	for each in c:
		for i in (0,1,2):
			each[i]=each[i]/255.
	scene.forward=[0.5,-0.5,-1]

init()

def tenblocks(firstblock=0):
	global pause
	for i in range(10):
		box(color=c[i],pos=(0,0,-firstblock + 10 -i))
		print scene.forward
		if pause>0.1:
			pause= pause * 0.99
			sleep(pause)

def ShowUpTo(Number=50):
	Tens=Number/10
	for i in range(Tens):
		tenblocks(firstblock=i*10)

ShowUpTo(Number=100)

Re: [Visualpython-users] controlling zooming

[Bruce S. <bas...@un...>]

Jon Schull is correct; there is something wrong with autoscaling when
scene.forward is not along z. Thanks for reporting this. The autoscaling
seems to be based on the view seen with the default scene.forward rather
than the actual scene.forward.

The other problem he reported, "When I fiddle with scene.range, the image
gets dim as if the lights have been turned down," was basically due to the
fact that the blocks lie along the z axis and so only the single front face
is directly illuminated. The color problem was compounded by setting RGB
values to a maximum of 255 rather than 1, which gives strange results. The
version of the program below resets the RGB values to be within the valid
parameter range. One might also change the direction of the lighting so that
the side faces of the blocks are directly illuminated. (When running the
program, click to advance.)

from visual import *

##"jon schull" <js...@so...>
##This program builds blocks out into space correctly, but it automatically
##"zooms" way out (too far out) about midway through.

c=[]
def init():
    for i in range(10):
        c.append((0,0,0))

    c[0]=[255,255,255]
    c[1]=[255,153,51]
    c[2]=[102,102,153]
    c[3]=[255,0,102]
    c[4]=[102,102,153]
    c[5]=[255,102,0]
    c[6]=[128,0,128]
    c[7]=[255,255,0]
    c[8]=[51,51,153]
    c[9]=[255,0,102]

    for i in range(10):
        for j in range(3):
            c[i][j] = c[i][j]/255.0

for each in c:
    for i in (0,1,2):
        each[i]=each[i]/255.
scene.forward=[0.5,-0.5,-1]
scene.range=10 ## added to avoid the autoscaling problem

init()

def tenblocks(firstblock=0):
    for i in range(10):
        b = box(color=c[i],pos=(0,0,-firstblock + 10 -i))
    scene.mouse.getclick()

def ShowUpTo(Number=50):
    Tens=Number/10
    for i in range(Tens):
        tenblocks(firstblock=i*10)

ShowUpTo(Number=100)

RE: [Visualpython-users] controlling zooming

[jon s. <js...@so...>]

Thanks for your help!

Attached is the kind of image I'm working on (its the decimal system
visualized).

Is there a way of adjusting the foreshortening?  When I zoom closer to the
nearest point (the 0) it disappears (perhaps I'm too close to the camera).
I'd like to see more of the single-digit integers and be able to see detail
a few orders of magnitude further.

I think if I could have the camera "way back"  but telescope in to the
object of interest, the foreshortening would be reduced..?


------------------------------------------
Jonathan Schull, Ph.D.
Sc...@Di... <mailto:Sc...@Di...>
http://radio.weblogs.com/0104369/stories/2002/09/24/JonathanSchullOnOnePage.
html
<http://radio.weblogs.com/0104369/stories/2002/09/24/JonathanSchullOnOnePage
.html>
36 Brunswick St., Rochester NY 14607
585-738-6696 cell and v-mail
585-242-9497 landline
978-246-0487 fax
------------------------------------------



> -----Original Message-----
> From: vis...@li...
> [mailto:vis...@li...]On Behalf Of
> Bruce Sherwood
> Sent: Wednesday, January 01, 2003 8:20 PM
> To: vis...@li...
> Subject: Re: [Visualpython-users] controlling zooming
>
>
> Jon Schull is correct; there is something wrong with autoscaling when
> scene.forward is not along z. Thanks for reporting this. The autoscaling
> seems to be based on the view seen with the default scene.forward rather
> than the actual scene.forward.
>
> The other problem he reported, "When I fiddle with scene.range, the image
> gets dim as if the lights have been turned down," was basically due to the
> fact that the blocks lie along the z axis and so only the single
> front face
> is directly illuminated. The color problem was compounded by setting RGB
> values to a maximum of 255 rather than 1, which gives strange results. The
> version of the program below resets the RGB values to be within the valid
> parameter range. One might also change the direction of the
> lighting so that
> the side faces of the blocks are directly illuminated. (When running the
> program, click to advance.)
>
> from visual import *
>
> ##"jon schull" <js...@so...>
> ##This program builds blocks out into space correctly, but it
> automatically
> ##"zooms" way out (too far out) about midway through.
>
> c=[]
> def init():
>     for i in range(10):
>         c.append((0,0,0))
>
>     c[0]=[255,255,255]
>     c[1]=[255,153,51]
>     c[2]=[102,102,153]
>     c[3]=[255,0,102]
>     c[4]=[102,102,153]
>     c[5]=[255,102,0]
>     c[6]=[128,0,128]
>     c[7]=[255,255,0]
>     c[8]=[51,51,153]
>     c[9]=[255,0,102]
>
>     for i in range(10):
>         for j in range(3):
>             c[i][j] = c[i][j]/255.0
>
> for each in c:
>     for i in (0,1,2):
>         each[i]=each[i]/255.
> scene.forward=[0.5,-0.5,-1]
> scene.range=10 ## added to avoid the autoscaling problem
>
> init()
>
> def tenblocks(firstblock=0):
>     for i in range(10):
>         b = box(color=c[i],pos=(0,0,-firstblock + 10 -i))
>     scene.mouse.getclick()
>
> def ShowUpTo(Number=50):
>     Tens=Number/10
>     for i in range(Tens):
>         tenblocks(firstblock=i*10)
>
> ShowUpTo(Number=100)
>
>
>
>
> -------------------------------------------------------
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> _______________________________________________
> Visualpython-users mailing list
> Vis...@li...
> https://lists.sourceforge.net/lists/listinfo/visualpython-users
>

Re: [Visualpython-users] controlling zooming

[Bruce S. <bas...@un...>]

I don't really understand what you're trying to achieve, and the display is
very far away after autoscaling and therefore requires huge zooming to see
anything, so I may miss the mark in trying to respond to your questions. I'm
guessing though that what you're looking for is scene.fov. From the Visual
reference manual:

Field of view of the camera in radians. This is defined as the maximum of
the horizontal and vertical fields of view. You can think of it as the
angular size of an object of size range, or as the angular size of the
longer axis of the window as seen by the user. Default pi/3.0 radians (60
degrees).

Bruce Sherwood

----- Original Message -----
From: "jon schull" <js...@so...>
To: <vis...@li...>
Sent: Thursday, January 02, 2003 8:43 PM
Subject: RE: [Visualpython-users] controlling zooming


> Thanks for your help!
>
> Attached is the kind of image I'm working on (its the decimal system
> visualized).
>
> Is there a way of adjusting the foreshortening?  When I zoom closer to the
> nearest point (the 0) it disappears (perhaps I'm too close to the camera).
> I'd like to see more of the single-digit integers and be able to see
detail
> a few orders of magnitude further.
>
> I think if I could have the camera "way back"  but telescope in to the
> object of interest, the foreshortening would be reduced..?