visualpython-users

[Visualpython-users] Best way to position fixed text ?

[Stef M. <s.m...@ru...>]

hello,

The label item has nice properties to position the text absolute in a frame,
through xoffset / yoffset,
so it's not affected by zooming.

But it's still moves when the window is resized.

Now the windows parameters width and height are not available, when the 
window is shown.
Therefor it doesn't seem possible to position the text in the upper left 
corner and keep it there,
unless you place the center in the upper left corner.

How are others position fixed texts ?
(btw most scripts I've seen now, doesn't use xoffset / yoffset, why ? )

thanks,
Stef

Re: [Visualpython-users] Is it possible to reset the userzoom (VP3) ?

[Stef M. <s.m...@ru...>]

thanks Bruce,

I've it finally working,
and had a lot of trouble because of some strange timing issues:
Basically this is the code:

    scene.forward = Temp_Forward
    scene.up = Up
    scene.forward = Forward

    time.sleep ( 0.1 )
    a = mag ( scene.mouse.camera ) / abs ( Scale )
    scene.scale = a * scene.scale

where Up, Forward and Scale are a constants given by the designer.
Temp_Forward is a calculated value to prevent parallelism of Up and Forward
Now this only works,
if the delay of about 100 msec is inserted,
why ???
( I couldn't find anything in the documentation, but that happened 
before ;-)
At other places I've also seen that scene.mouse.camera is the zero vector,
if placed to soon in the program.
Looks like a similar effect to me.
Any explanation ?

thanks,
Stef


Bruce Sherwood wrote:
> There really isn't a fully functional way, though see movecamera.py in 
> the VPython 3 contributed programs.
>
> Bruce Sherwood
>
> Stef Mientki wrote:
>> hello,
>>
>> I've made an overview of VPython applications.
>> Now I can easily switch from 1 example to another,
>> reset all default values of the scene,
>> and watch another demo.
>>
>> But there's one parameter I can't find how to control,
>> and that's the user zoom.
>> It seems that the shown image is something like Range * UserZoom (if 
>> it's called that way).
>>
>> Is there a way to reset the user zoom (VPython 3) ?
>>
>> thanks,
>> Stef Mientki
>>
>>
>> ------------------------------------------------------------------------------ 
>>
>> _______________________________________________
>> Visualpython-users mailing list
>> Vis...@li...
>> https://lists.sourceforge.net/lists/listinfo/visualpython-users
>>   
>
>

[Visualpython-users] Fwd: Re: Robot Simulator in vPython, PyODE, and wxPython

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

Resent due to our terminal network failure at uni yesterday.

----------  Forwarded Message  ----------

Sweet!

I have proposed a good year ago pretty much *exactly* the same as a project 
for some honours student. But apparently everybody here at our uni was too 
afraid of Python and this "magical" looking stuff ... :-(

Keep it up,

Guy

-- 
Guy K. Kloss
Institute of Information and Mathematical Sciences
Te Kura Pūtaiao o Mōhiohio me Pāngarau
Room 2.63, Quad Block A Building
Massey University, Auckland, Albany
Private Bag 102 904, North Shore Mail Centre
voice: +64 9 414-0800 ext. 9585   fax: +64 9 441-8181
eMail: G....@ma...  http://iims.massey.ac.nz

Re: [Visualpython-users] Robot Simulator in vPython, PyODE, and wxPython

[Stef M. <s.m...@ru...>]

hello ...

very nice !
And it still works perfectly under VPython 3.
In VP-5 the middle mouse zoom bug appears ;-)
I didn't install PyODE, but I had already Scipy installed,
and I guess it's getting the ode solver from there.
Hope to see more of your creations in the future.

cheers,
Stef

CL wrote:
> I've packed the source code for a robot simulator for your reference.
>
> http://code.google.com/p/clrobotsim/
>
> The simulator performs a simulation for a DIY robot, you can take a look here:
> http://www.youtube.com/watch?v=puwZhbTOOqE
> http://www.youtube.com/watch?v=K15FfdML6mk
>
> BTW, my skill on python, vpython, pyode, is average only. Let me know
> if you find any problems in the source code. It is only tested on my
> PC (Windows XP) and never tested on other platform and hardware.
>
> The original program was running on vpython 3.x, and recently moved to
> 5.0. I have not used any new feature in 5.0 yet, because my video card
> is quite old already. I only find the scene.hide() function is not
> there any more, other than that, there is no change in the migration.
>
> ------------------------------------------------------------------------------
> _______________________________________________
> Visualpython-users mailing list
> Vis...@li...
> https://lists.sourceforge.net/lists/listinfo/visualpython-users
>
>
>   

[Visualpython-users] Visual 5.01 for Linux

[Bruce S. <Bru...@nc...>]

008-12-31 Visual 5.01 for Linux corrects an error in the size attribute 
of the points object. New documentation of size and shape attributes for 
graphing gdots. Package now includes threadpool files.

Bruce Sherwood

Re: [Visualpython-users] Robot Simulator in vPython, PyODE, and wxPython

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

Sweet!

I have proposed a good year ago pretty much *exactly* the same as a project 
for some honours student. But apparently everybody here at our uni was too 
afraid of Python and this "magical" looking stuff ... :-(

Keep it up,

Guy

-- 
Guy K. Kloss
Institute of Information and Mathematical Sciences
Te Kura Pūtaiao o Mōhiohio me Pāngarau
Room 2.63, Quad Block A Building
Massey University, Auckland, Albany
Private Bag 102 904, North Shore Mail Centre
voice: +64 9 414-0800 ext. 9585   fax: +64 9 441-8181
eMail: G....@ma...  http://iims.massey.ac.nz

[Visualpython-users] Robot Simulator in vPython, PyODE, and wxPython

[CL <clc...@gm...>]

I've packed the source code for a robot simulator for your reference.

http://code.google.com/p/clrobotsim/

The simulator performs a simulation for a DIY robot, you can take a look here:
http://www.youtube.com/watch?v=puwZhbTOOqE
http://www.youtube.com/watch?v=K15FfdML6mk

BTW, my skill on python, vpython, pyode, is average only. Let me know
if you find any problems in the source code. It is only tested on my
PC (Windows XP) and never tested on other platform and hardware.

The original program was running on vpython 3.x, and recently moved to
5.0. I have not used any new feature in 5.0 yet, because my video card
is quite old already. I only find the scene.hide() function is not
there any more, other than that, there is no change in the migration.

[Visualpython-users] points and gdots

[Bruce S. <Bru...@nc...>]

2008-12-30 Visual 5.01 for Windows and Mac corrects an error in the size 
attribute of the points object. New documentation of size and shape 
attributes for graphing gdots. Linux version not corrected yet.

Bruce Sherwood

Re: [Visualpython-users] updating Mac Python

[Bruce S. <Bru...@nc...>]

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
  <meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type">
</head>
<body bgcolor="#ffffff" text="#000000">
>From the VPython wiki, here is my response to a question about Python
2.6:<br>
<div class="content" id="post-content-288920">
<p>Indeed, the version of Visual has to have been built for a specific
version of Python, and a mismatch cannot work. Just this week I worked
a bit with Python 2.6 to see what the issues are going to be. There are
some problems. The Boost libraries, which enhance C++, have to be built
for a specific version of Python, and since there aren't yet available
these binaries for 2.6, I built them from source. Similarly for numpy.
Turns out that something has changed in these components, because
there's now a type mismatch between numpy integers and Python integers
(this is a simplified description). Moreover, for the new Visual about
to be released, there's a problem with a native-mode version for the
Mac because the Mac Python 2.6 has an IDLE that won't run!</p>
<p>Summary: There are various problems in the Python 2.6 world. But
we'll be tracking them and looking for solutions. We would prefer to
release the new Visual for Python 2.6, because the new Python builds a
bridge between Python 2.5 and the coming Python 3.0, a version of
Python that will actually break some existing programs. Python 2.6
offers tools to check on possible incompatibilities.</p>
<p>------------------------<br>
</p>
<p>Also, from James Mueller:<br>
</p>
<p>2.6 only came out in October, so numpy will probably be less than 6
months behind.&nbsp; It would be earlier, but they have other things to take
care of first.&nbsp; Most linux distributions are planning to roll out 2.6
over the next 6 months, so that is the time scale they are looking at.&nbsp;
2.6 might also be the python when OS X 10.6 comes out.&nbsp;&nbsp; 3.0 is a BIG
change, which is why they estimate a year to get numoy ported.&nbsp; I
expect a lot of projects will take some time to move from the 2.x
series to 3.x.&nbsp; There are a lot of non-backward-compatible syntax
changes.
</p>
</div>
<br>
Joe Heafner wrote:
<blockquote
 cite="mid:e7f...@ma..."
 type="cite">Would updating Mac Python from 2.5.2 to 2.6.x break the
latest Visual?
  <div><br>
  </div>
  <div>Joe</div>
  <pre wrap="">
<hr size="4" width="90%">
------------------------------------------------------------------------------
  </pre>
  <pre wrap="">
<hr size="4" width="90%">
_______________________________________________
Visualpython-users mailing list
<a class="moz-txt-link-abbreviated" href="mailto:Vis...@li...">Vis...@li...</a>
<a class="moz-txt-link-freetext" href="https://lists.sourceforge.net/lists/listinfo/visualpython-users">https://lists.sourceforge.net/lists/listinfo/visualpython-users</a>
  </pre>
</blockquote>
</body>
</html>

[Visualpython-users] updating Mac Python

[Joe H. <hea...@gm...>]

Would updating Mac Python from 2.5.2 to 2.6.x break the latest Visual?
Joe

Re: [Visualpython-users] dotsize and linewidth

[Bruce S. <Bru...@nc...>]

The simplest answer is you can't.

More complicated answer:

The following statements will make a thick curve which may or may not do 
what you want, given that the x and y axes typically have different scales.

f  = gcurve() # creates a gcurve object; f.gcurve is the curve used to 
display
f.gcurve.radius = 2

In Visual 3, gdots were implemented with labels containing letter o's. 
See the "class gdots" section of visual.graph.

In Visual 5, gdots are implemented with the new points object which 
should permit the specifying of size, but I see that something's broken 
with the size attribute of points.

Bruce Sherwood

Poul Riis wrote:
> How can I control the dot size in gdots and the line width in gcurve?
>
> Poul Riis
>
>
> ------------------------------------------------------------------------------
> _______________________________________________
> Visualpython-users mailing list
> Vis...@li...
> https://lists.sourceforge.net/lists/listinfo/visualpython-users
>   

Re: [Visualpython-users] event driven programming

[Bruce S. <Bru...@nc...>]

This code fragment displays a blue sphere named ball, then enters an 
infinite loop looking for mouse events. If you click on the ball, the 
ball is "picked" and its color is changed to red:

from visual import *
ball=sphere(color=color.blue)
while True:
    if scene.mouse.events:
        m = scene.mouse.getevent()
        if m.pick is ball:
            ball.color = color.red

Mr Gerard Kelly wrote:
> Hi, I'm new to using Python and I haven't looked at VPython yet, but I
> was just wondering about what it can do. Is it possible to create an
> event-driven 3D model, as in it responds to pointing and clicking on the
> actual graph itself (for instance, clicking on a ball makes it change
> color, or move, or something like that)?
>
> ------------------------------------------------------------------------------
> _______________________________________________
> Visualpython-users mailing list
> Vis...@li...
> https://lists.sourceforge.net/lists/listinfo/visualpython-users
>   

[Visualpython-users] dotsize and linewidth

[Poul R. <Pou...@sk...>]

How can I control the dot size in gdots and the line width in gcurve?

Poul Riis

[Visualpython-users] event driven programming

[Mr G. K. <s40...@st...>]

Hi, I'm new to using Python and I haven't looked at VPython yet, but I
was just wondering about what it can do. Is it possible to create an
event-driven 3D model, as in it responds to pointing and clicking on the
actual graph itself (for instance, clicking on a ball makes it change
color, or move, or something like that)?

[Visualpython-users] Parallelism of forward and up ...

[Stef M. <s.m...@ru...>]

hello,

while trying to get the correct the user zoom changed by code (as Bruce 
suggested),
I bounced into another problem, parallelism of up and forward.
Normally this problem won't occur, but switching between application, 
made by different persons,
within the same scene (as I do right now) can cause this problem.
So I've made a convenience procedure to prevent the problem,
maybe some of you might benefit from it ,...
... or even have better (simpler) solutions.
cheers,
Stef


# ***********************************************************************
def Forward_Up ( Forward, Up ) :
  """
  Sets both FORWARD and UP,
  preventing temporary parallelism of FORWARD and UP
  """
  # Be sure we've vectors
  Forward = vector ( Forward )
  Up      = vector ( Up      )

  # Temp_Forward should not allign with
  #   1. scene.up
  #   2. Up
  #   3. Forward
  # And we may assume that Up and Forward don't allign
  # The sum of Forward and Up, will fullfill conditions 2,3
  Temp_Forward = Up + Forward

  # calculate alfa, critical a=0  and alfa=pi
  alfa = Temp_Forward.diff_angle ( scene.up )
  # make alfa in range 0 .. pi/2, critical alfa = pi/2
  alfa = abs ( alfa - pi/2 )
  # make alfa in range pi/2 .. 0, critical alfa = 0
  alfa = pi/2 - alfa
  # if Temp_Forward alligned with current scene.up
  if alfa < 0.1 :
    # Create the product vector,
    # which is perpendicular to Up and Forward (conditions 2,3)
    # and will not allign with scene.up
    Temp_Forward = dot ( Up, Forward )

  scene.forward = Temp_Forward
  scene.up = Up
  scene.forward = Forward

[Visualpython-users] DELETE My name

[R.M. SPERANDEO-M. <spe...@di...>]

Please delete my e-mail address from the list
===================================
Prof. R. M. Sperandeo-Mineo
Dipartimento di Fisica e Tecnologie Relative
Università di Palermo
Viale delle Scienze (Edificio 18)
90128-Palermo (Italy)
Tel: +39-091-6615101
Fax: +39-091-6615107
E_mail: spe...@di...
http://www.griaf.unipa.it
  ----- Original Message ----- 
  From: symion 
  To: Visual Python 
  Sent: Saturday, December 27, 2008 1:17 PM
  Subject: [Visualpython-users] tools


  Here is another program related to big spaces. MeasuringStick.py
  A measuring stick that uses a simple line drawing tool with point and click.
  The simulation is a Sun/Earth gravity gradient that you can use to measure the distance of various objects.

  New Year wish list:

  Two new methods for display():
  scene.spin : a replacement to scene.forward for reading and writing user spin input
  scene.zoom : a new method for reading and writing user based zoom input

  This would leave scene.range/scale for defining overall scene settings and make scene.forward redundant.

  Scene.zoom should set and get user driven zoom values in the same way that scene.forward returns user spin values.

  The purpose of this would be to enable programs to turn on or off labels and other objects when user zooms in to field of view or zooms out, respectively.
  Also, such methods would make it very easy to design a Vpython Scene Animator, driven by a user input stream of spin and zoom and capable of producing smooth, time based Fly-Throughs of ANY scene.

  Any how, I'm taking a break for a few days.

  Happy New Year to Everyone on the mailing list.

  Symion



------------------------------------------------------------------------------


  ------------------------------------------------------------------------------



------------------------------------------------------------------------------


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  Visualpython-users mailing list
  Vis...@li...
  https://lists.sourceforge.net/lists/listinfo/visualpython-users

Re: [Visualpython-users] error: Linking with uncompiled shader

[Bruce S. <Bru...@nc...>]

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
  <meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type">
</head>
<body bgcolor="#ffffff" text="#000000">
>From the "New features" documentation for Visual 5:<br>
<br>
"Materials will work with graphics cards that support Pixel Shader 3.0
("PS 3.0"). For details, see<br>
<a href="http://en.wikipedia.org/wiki/Pixel_shader#Hardware"
 target="_blank">http://en.wikipedia.org/wiki/Pixel_shader#Hardware</a>.
<em>Some</em> materials may work with graphics cards that support PS
2.0, but other materials may need to be manually disabled; see
instructions in the <strong>site-settings.py</strong> module in the
Visual package in your site-packages folder. If the graphics hardware
does not support pixel shaders, the material property is ignored. If
you think you should be able to use materials but have trouble with
their display or performance, we highly recommend upgrading your video
card drivers to the latest version."<br>
<br>
The wikipedia article shows that the Intel GMA X3100 doesn't support PS
3.0, so you might want to modify site-settings.py as explained above.<br>
<br>
Can you run a simple program like bounce2.py, which doesn't involve
material properties?<br>
<br>
Can you be more specific about what is meant by "closing its windows
without being properly required to"? What programs? Do you see a
graphics window and a scene for a while before the crash?<br>
<br>
Bruce Sherwood<br>
<br>
Anselmo Pitombeira wrote:
<blockquote cite="mid:495...@ya..." type="cite">
  <pre wrap="">I have just installed vpython 5.0, and I get this message any time I run 
an example:

VPython WARNING: errors in shader program:
linking with uncompiled shader


My system is:

Ubuntu 8.10 Intrepid Ibex
Video card: Intel GMA X3100

I have the following libraries installed:

libgl1-mesa-dri 7.2
libgl1-mesa-glx 7.2

I can run some of the examples, but they exhibit erroneous behaviour, as 
closing its windows  without being properly required to.


I am grateful for any help.


Ragards


Anselmo

  </pre>
</blockquote>
</body>
</html>

Re: [Visualpython-users] Is it possible to reset the userzoom (VP3) ?

[Bruce S. <Bru...@nc...>]

There really isn't a fully functional way, though see movecamera.py in 
the VPython 3 contributed programs.

Bruce Sherwood

Stef Mientki wrote:
> hello,
>
> I've made an overview of VPython applications.
> Now I can easily switch from 1 example to another,
> reset all default values of the scene,
> and watch another demo.
>
> But there's one parameter I can't find how to control,
> and that's the user zoom.
> It seems that the shown image is something like Range * UserZoom (if 
> it's called that way).
>
> Is there a way to reset the user zoom (VPython 3) ?
>
> thanks,
> Stef Mientki
>
>
> ------------------------------------------------------------------------------
> _______________________________________________
> Visualpython-users mailing list
> Vis...@li...
> https://lists.sourceforge.net/lists/listinfo/visualpython-users
>   

[Visualpython-users] Is it possible to reset the userzoom (VP3) ?

[Stef M. <s.m...@ru...>]

hello,

I've made an overview of VPython applications.
Now I can easily switch from 1 example to another,
reset all default values of the scene,
and watch another demo.

But there's one parameter I can't find how to control,
and that's the user zoom.
It seems that the shown image is something like Range * UserZoom (if 
it's called that way).

Is there a way to reset the user zoom (VPython 3) ?

thanks,
Stef Mientki

[Visualpython-users] error: Linking with uncompiled shader

[Anselmo P. <ans...@ya...>]

I have just installed vpython 5.0, and I get this message any time I run 
an example:

VPython WARNING: errors in shader program:
linking with uncompiled shader


My system is:

Ubuntu 8.10 Intrepid Ibex
Video card: Intel GMA X3100

I have the following libraries installed:

libgl1-mesa-dri 7.2
libgl1-mesa-glx 7.2

I can run some of the examples, but they exhibit erroneous behaviour, as 
closing its windows  without being properly required to.


I am grateful for any help.


Ragards


Anselmo

-- 
Me. Eng. Anselmo Pitombeira

Doutorando em Engenharia Mecânica
Laboratório de Simulação e Controle
EESC-USP

+55 85 8700 8855 / +55 85 3081 0952

[Visualpython-users] Simple Animator

[symion <sy...@pr...>]

Oops made a mistake with the file path. try this!
I have a working example of a simple animator that allows you to record 
and playback zoom based fly-throughs of a simple scene.
Currently it is just a ball and two cubes, but you can insert any scene 
you like.

The source code is here 
<http://home.primusonline.com.au/knoware/python/animator-1.py>Animator-1.py 
<http://home.primusonline.com.au/knoware/python/animator-1.py>

It has no methods for saving your efforts, yet!

Note scene.userzoom is redundant and actually gets in the way so it is 
turned off.

Symion

[Visualpython-users] Simple Animator

[symion <sy...@pr...>]

I have a working example of a simple animator that allows you to record 
and playback zoom based fly-throughs of a simple scene.
Currently it is just a ball and two cubes, but you can insert any scene 
you like.

The source code is here Animator-1.py 
<http://home.primusonline.com.au/python/animator-1.py>

It has no methods for saving your efforts, yet!

Note scene.userzoom is redundant and actually gets in the way so it is 
turned off.

Symion

Re: [Visualpython-users] tools

[Bruce S. <Bru...@nc...>]

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
  <meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type">
</head>
<body bgcolor="#ffffff" text="#000000">
There's no obstacle at present to creating fly-throughs, is there? An
example is stonehenge.py, where one simply updates scene.center and
scene.forward to implement the fly-through.<br>
<br>
Bruce Sherwood<br>
<br>
symion wrote:
<blockquote cite="mid:495...@pr..." type="cite"><font
 size="-1"><font face="Helvetica, Arial, sans-serif">Here is
another program related to big spaces. <a moz-do-not-send="true"
 href="http://home.primusonline.com.au/knoware/python/measuringstick.py">MeasuringStick.py</a><br>
A measuring stick that uses a simple line drawing tool with point and
click.<br>
The simulation is a Sun/Earth gravity gradient that you can use to
measure the distance of various objects.<br>
  <br>
New Year wish list:<br>
  <br>
Two new methods for display():<br>
scene.spin : a replacement to scene.forward for reading and writing
user spin input<br>
scene.zoom : a new method for reading and writing user based zoom input<br>
  <br>
This would leave scene.range/scale for defining overall scene settings
and make scene.forward redundant.<br>
  <br>
Scene.zoom should set and get user driven zoom values in the same way
that scene.forward returns user spin values.<br>
  <br>
The purpose of this would be to enable programs to turn on or off
labels and
other objects when user zooms in to field of view or zooms out,
respectively.<br>
Also, such methods would make it very easy to design a Vpython Scene
Animator, driven by a user input stream of spin and zoom and capable of
producing smooth, time based Fly-Throughs of ANY scene.<br>
  <br>
Any how, I'm taking a break for a few days.<br>
  <br>
Happy New Year to Everyone on the mailing list.<br>
  <br>
Symion</font></font></blockquote>
</body>
</html>

[Visualpython-users] tools

[symion <sy...@pr...>]

Here is another program related to big spaces. MeasuringStick.py 
<http://home.primusonline.com.au/knoware/python/measuringstick.py>
A measuring stick that uses a simple line drawing tool with point and click.
The simulation is a Sun/Earth gravity gradient that you can use to 
measure the distance of various objects.

New Year wish list:

Two new methods for display():
scene.spin : a replacement to scene.forward for reading and writing user 
spin input
scene.zoom : a new method for reading and writing user based zoom input

This would leave scene.range/scale for defining overall scene settings 
and make scene.forward redundant.

Scene.zoom should set and get user driven zoom values in the same way 
that scene.forward returns user spin values.

The purpose of this would be to enable programs to turn on or off labels 
and other objects when user zooms in to field of view or zooms out, 
respectively.
Also, such methods would make it very easy to design a Vpython Scene 
Animator, driven by a user input stream of spin and zoom and capable of 
producing smooth, time based Fly-Throughs of ANY scene.

Any how, I'm taking a break for a few days.

Happy New Year to Everyone on the mailing list.

Symion

Re: [Visualpython-users] critical error report

[Bruce S. <Bru...@nc...>]

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
  <meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type">
  <title></title>
</head>
<body bgcolor="#ffffff" text="#000000">
Thanks for the report. We need to check for the zoom distance being too
large or too small to represent with floating-point numbers. For
instance, zooming in and in and in there is a crash when the camera
distance is about 1e-330, similar issue in zooming way out. But as you
saw, you have to work very hard to get to these limits!<br>
<br>
The range/distance issue is a long-standing problem. One way of
characterizing it is that user zoom involves an internal scale factor
that's not visible to the program. I think that the only significant
change from Visual 3 is to give an error on trying to read the range in
the autoscale condition, where it is either meaningless or misleading.
I'm hopeful in 5.x that we'll come up with a better scheme. In the
meantime, it would be useful to have simple examples of situations that
you can't manage adequately in the current scheme.<br>
<br>
The range has never changed when you zoom. That too is like Visual 3.<br>
<br>
Bruce Sherwood<br>
<br>
symion wrote:
<blockquote cite="mid:495...@pr..." type="cite"><font
 size="-1"><font face="Helvetica, Arial, sans-serif">I have been
testing Vpython</font></font><font size="-1"><font
 face="Helvetica, Arial, sans-serif">, looking for boundaries.</font></font><br>
  <br>
  <font size="-1"><font face="Helvetica, Arial, sans-serif">IDLE just
through up an error.<br>
  </font></font><font size="-1"><font
 face="Helvetica, Arial, sans-serif"><br>
I was zooming in to a simple scene, looking for limits<br>
Zooming in </font></font><font size="-1"><font
 face="Helvetica, Arial, sans-serif">to destruction.<br>
  <br>
  </font></font><small>Here is the code snippet that was running,
although I have run
other bits of code and found the same result.<br>
  <br>
  </small><font size="-1"><font face="Helvetica, Arial, sans-serif">r=1.49e+15<br>
  </font></font><font size="-1"><font
 face="Helvetica, Arial, sans-serif">cur=[(0,0,0),(r,0,0)]</font></font><br>
  <font size="-1"><font face="Helvetica, Arial, sans-serif">p=points(pos=cur,color=(1,1,1))<br>
  <br>
Now zoom in</font></font><font size="-1"><font
 face="Helvetica, Arial, sans-serif"> and in, and in</font></font><font
 size="-1"><font face="Helvetica, Arial, sans-serif"> like a crazy man</font></font><font
 size="-1"><font face="Helvetica, Arial, sans-serif">, looking for that
boundary.</font></font><br>
  <br>
  <font size="-1"><font face="Helvetica, Arial, sans-serif">oops!<br>
  </font></font><font size="-1"><font
 face="Helvetica, Arial, sans-serif"><br>
VPython ***CRITICAL ERROR***: ..\src\core\display_kernel.cpp:909:
cvisual::display_kernel::render_scene: OpenGL error:
..\src\core\display_kernel.cpp:548 invalid value, aborting.<br>
  </font></font><font size="-1"><font
 face="Helvetica, Arial, sans-serif"><br>
Also, w</font></font><font size="-1"><font
 face="Helvetica, Arial, sans-serif">hen zooming out and out...</font></font><font
 size="-1"><font face="Helvetica, Arial, sans-serif"><br>
  <br>
VPython ***CRITICAL ERROR***: ..\src\core\display_kernel.cpp:535:
cvisual::display_kernel::world_to_view_transform: VPython degenerate
projection: 1.#INF 1.#INF 0.0500417 0.0315297<br>
  <br>
Yep, found the other one!<br>
  </font></font><font size="-1"><font
 face="Helvetica, Arial, sans-serif"><br>
Are the problems reported related to the apparent lack of any
clear range/scale boundaries?<br>
  <br>
Which leads me into the next question.<br>
  </font></font><font size="-1"><font
 face="Helvetica, Arial, sans-serif"><br>
I am having problems with scene.range. I expect it to be
connected to user zoom, so I can measure user input, just like
scene.forward method.<br>
  <br>
This is what I have found.<br>
If I run any program without setting scene.range then a default value
seems to be used and the program runs OK, but if I then try to read the
current scene.range,
IDLE displays the following warning.<br>
  <br>
Traceback (most recent call last):<br>
&nbsp; File "&lt;pyshell#1&gt;", line 1, in &lt;module&gt;<br>
&nbsp;&nbsp;&nbsp; scene.range<br>
RuntimeError: Reading .scale and .range is not supported when autoscale
is enabled.<br>
  <br>
Now if I change the program so that scene.range is set to some
arbitrary value and then run it, then the program runs OK, no problems,
and reading scene.range
returns the exact value I gave it! (which is kind of redundant) <br>
  <br>
But when as a user I zoom in or out, and then read scene.range, nothing
happens! the value is as I had previously set, no user actions are
recorded by scene.range!<br>
  </font></font><font size="-1"><font
 face="Helvetica, Arial, sans-serif"><br>
  </font></font><font size="-1"><font
 face="Helvetica, Arial, sans-serif">if
scene.userzoom and scene.range are not connected</font></font><font
 size="-1"><font face="Helvetica, Arial, sans-serif">, then how can I
(or my program) determine the current user zoom
value?<br>
  <br>
  </font></font><font size="-1"><font
 face="Helvetica, Arial, sans-serif">Symion</font></font><font size="-1"><font
 face="Helvetica, Arial, sans-serif"><br>
  </font></font>
  <br>
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  </pre>
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