visualpython-users

Re: [Visualpython-users] Advice for experienced programmers

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

Thanks! Updated.

Bruce Sherwood

Douglas S. Blank wrote:
> A couple of typos etc:
> 
> You refer to positions in mytup with mytup(1) which should be mytup[1].
> 
> Your html document doesn't have a TITLE section.
> 
> Also, your class names have lowercase letters and your instance names have
> uppercase letters. Maybe better to start out these Python newb's on the
> right foot :)
> 
> I think many experienced programmers might like ipython, too. Might be
> worth mentioning.
> 
> Thanks for the notes; I'll point people to it!
> 
> -Doug
> 
> On Thu, February 22, 2007 11:37 pm, Bruce Sherwood said:
> 
>> From time to time I've seen colleagues with extensive programming
>>experience but who are new to Python trip over some aspects of Python
>>that are different and unexpected. In response I've written a note about
>>what I perceive to be the most common traps and posted the note on the
>>home page of vpython.org (labeled "Python for experienced programmers").
>>
>>If you see some other issues that should be included in this summary,
>>I'd be grateful to have them pointed out.
>>
>>And if you think this might be useful elsewhere within the Python
>>community, feel free to point people to it or copy it to other places.
>>
>>Thanks.
>>
>>Bruce Sherwood
> 
> 
> 

[Visualpython-users] Advice for experienced programmers

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

 From time to time I've seen colleagues with extensive programming 
experience but who are new to Python trip over some aspects of Python 
that are different and unexpected. In response I've written a note about 
what I perceive to be the most common traps and posted the note on the 
home page of vpython.org (labeled "Python for experienced programmers").

If you see some other issues that should be included in this summary, 
I'd be grateful to have them pointed out.

And if you think this might be useful elsewhere within the Python 
community, feel free to point people to it or copy it to other places.

Thanks.

Bruce Sherwood

Re: [Visualpython-users] The Fate of PyGeo

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

I have no knowledge of the possible fate of PyGeo. I don't know whether 
Arthur had collaborators on PyGeo, and I don't know what SourceForge 
would do if someone came forward to volunteer to take over the project.

Bruce Sherwood

Joel Kahn wrote:
> Bruce Sherwood posted the grim news:
> 
> 
>>Arthur Jay Siegel, 55, died Tuesday evening of an unexpected heart 
>>attack. An international business consultant and a self-taught 
>>mathematician/computer scientist, he invented PyGeo--a software used
> 
> 
>>to create interactive, three-dimensional geometric spaces. . . .
> 
> 
> With Art gone, is anyone working on PyGeo? The system has some very
> interesting and useful features, and it would be a pity for it to
> fade away as orphanware. Perhaps the same people at NSF who arranged
> the VPython grant might be interested in supporting future PyGeo
> development. Any ideas/suggestions, Bruce & company?
> 
> Joel
> 
> 
> 
>  
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[Visualpython-users] The Fate of PyGeo

[Joel K. <jj...@ya...>]

Bruce Sherwood posted the grim news:

>Arthur Jay Siegel, 55, died Tuesday evening of an unexpected heart 
>attack. An international business consultant and a self-taught 
>mathematician/computer scientist, he invented PyGeo--a software used

>to create interactive, three-dimensional geometric spaces. . . .

With Art gone, is anyone working on PyGeo? The system has some very
interesting and useful features, and it would be a pity for it to
fade away as orphanware. Perhaps the same people at NSF who arranged
the VPython grant might be interested in supporting future PyGeo
development. Any ideas/suggestions, Bruce & company?

Joel



 
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Re: [Visualpython-users] povray

[Anton S. <ant...@gm...>]

Nils Wagner wrote:
> Is there a way to call povray from python ?
> I found out that it works for single input files
>
> import os
> os.system("povray quickres.ini'[640x480, AA 0.3]'+iwoodexample.pov +fn")
>
> but how can I apply povray to multiple files woodexample001.pov -
> woodexample009.pov ?

for filename in pov_file_list:
    os.system( "povray ... +i%s" % filename )

or, if the filenames are known to fit a pattern,

for n in range(count):
    os.system( "povray ... +iwoodexample%03d" % n )

(".pov" need not be specified in the +i field.)

-- 
Anton Sherwood, http://www.ogre.nu/

Re: [Visualpython-users] How to build visualpython via cvs

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

The package "vpython" is the stable version in CVS.

The package "vpython-core2" is the beta version with many enhancements 
(see the "Recent developments" section of vpython.org). It has serious 
bugs on Windows but seems to work okay on Linux.

Since the actual CVS tree for vpython-core2 is in some flux, you might 
better download visual-4.beta14.tar.bz2 from

	http://sourceforge.net/projects/visualpython

or visual-3.2.9.tar.bz2 for the stable version from vpython.org.

Bruce Sherwood

Nils Wagner wrote:
> Hi there,
> 
> Which packages do I need (cvisual,visual,vpython,vpython-core2)
> to build/install visualpython from cvs (Linux box OpenSuSE 10.2)
> 
> http://visualpython.cvs.sourceforge.net/visualpython/
> 
> Nils
> 

[Visualpython-users] povray

[Nils W. <nw...@ia...>]

Hi there,

Is there a way to call povray from python ?
I found out that it works for single input files

import os
os.system("povray quickres.ini'[640x480, AA 0.3]'+iwoodexample.pov +fn")

but how can I apply povray to multiple files woodexample001.pov -
woodexample009.pov ?

Any pointer ?

Nils

[Visualpython-users] How to build visualpython via cvs

[Nils W. <nw...@me...>]

Hi there,

Which packages do I need (cvisual,visual,vpython,vpython-core2)
to build/install visualpython from cvs (Linux box OpenSuSE 10.2)

http://visualpython.cvs.sourceforge.net/visualpython/

Nils

Re: [Visualpython-users] feature request

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

You can say a.norm().

Joe Heafner wrote:
> To compute the magnitdue of a vector, there are three
> options. One can do it explicitly in terms of a
> vector's components. One can use the mag(a) function.
> One can use the a.mag method to get the magnitude of
> a. It would be handy if there were a corresponding
> method for getting the norm of a vector, as in a.norm.
> There is already a norm() function so I'm thinking
> adding a method wouldn't be difficult.
> 
> Joe
> 
> 
>  
> ____________________________________________________________________________________
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[Visualpython-users] feature request

[Joe H. <bet...@ya...>]

To compute the magnitdue of a vector, there are three
options. One can do it explicitly in terms of a
vector's components. One can use the mag(a) function.
One can use the a.mag method to get the magnitude of
a. It would be handy if there were a corresponding
method for getting the norm of a vector, as in a.norm.
There is already a norm() function so I'm thinking
adding a method wouldn't be difficult.

Joe


 
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[Visualpython-users] In memory of Arthur

[Ting L. <dri...@gm...>]
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PiBCeSB0aGUgd2F5LCBJIHdvdWxkIGxpa2UgdG8gcmVtaW5kIHRoZSBhdXRob3JzLCB0aGUgc2lt
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ZSB0cnlpbmcgdG8gcHJvdmlkZSBtb3JlIQo+ICh5b3UgYXJlIHdvcmtpbmcgb24gYWRkaW5nIGxp
Z2h0aW5nLCB0ZXh0dXJlLCB0cmFuc3BhcmVuY3kuLi4pCj4gSXQgbG9va3MgbGlrZSBhIHJlYWwg
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QAo=

[Visualpython-users] a display problem with my Vpython program

[Ting L. <dri...@gm...>]

Hello,

I have a display problem with my Vpython program.
In the scene, I need to draw thousands of spheres and cylinders, and I
also need to switch the visibility of some groups of them on and off,
fast sometimes. I used a list to store all the objects and then loop
over each object to change its visible property.
The problem is
When I set visible to 1 for a group of objects by loop, then in the
following code I immediately change visible to 0 for a sub-group of
them, I found the whole group first displayed then the objects in the
sub-group disappeared (because I set them to be invisible). When I
repeat this procedure quickly, this problem cause ugly 'flashing'.
(some object appear then disappear.)

...
for o in objects:
	o.visible = 1
...
for o in objects[start:end]:
	o.visible = 0
...


Is there a better way to set the visibility of a group of objects more
efficiently?
According to the VPython doc, I can group some objects into one frame,
then I can move or rotate them as a whole. But to change the visible
property, I still need loop, right?

One guess of mine is this problem is related to the display mechanism
of Vpython.
VPython doesn't have a 'redraw' or 'UpdateView' or something like that
exposed to the user. Once you draw an object, it call the internal
'redraw' method implicitly.
If this is true, then I think we need an explicit 'redraw' method to
control the display of the scene we don't want them to display
immediately. This is in fact the intention of the 'double buffer' in
OpenGL.

I know I can combine the two loops into one if I can know the
visibility of all the objects in a prior. Thing maybe becomes better.
But the problem I explained above remains, because during the looping,
if an object will show up immediately after setting the 'visible=1',
the objects in the scene will look like cabbages emerging or growing
from underground!
I do prefer to hide them first and display all of them at the same time.

I have to say I'm not very familiar with Vpython. So if somebody can
help me to clarify these problems, it would be very appreciated!

Ting

Re: [Visualpython-users] Arthur Siegel

[Jon S. <js...@gm...>]

This is very sad news.

There was something special about Arthur--a dedication to beauty, clarity,
and a desire to make a contribution--that came though in his projects and in
his emails.



On 2/6/07, Bruce Sherwood <Bru...@nc...> wrote:
>
> From the New York Time obituaries:
>
> Arthur Jay Siegel
> SIEGEL - Arthur Jay , 55, died Tuesday evening of an unexpected heart
> attack. An international business consultant and a self-taught
> mathematician/computer scientist, he invented PyGeo - a software used to
> create interactive, three-dimensional geometric spaces. He grew up in
> East Meadow. He and his loving wife of 29 years, Carol, moved four years
> ago to Yorktown Heights. He treasured a close friendship with his son,
> Benjamin, 23. In addition to Ben and Carol, Arthur is survived by his
> father, Jacob Siegel, sisters Beth Siegel, Marian Siegel and Marsha
> Berzon and many loving nieces, nephews, cousins, in-laws and friends.
> Funeral services will be held at Riverside Memorial Chapel, 21 W. Broad
> Street, Mount Vernon, New York at noon on Sunday.
>
> --------------------------------------
>
> I'm thunderstruck by this bolt out of the blue. As you know, Arthur was
> doing wonderful work on the beta version of VPython. I never met him in
> person, but he was a good colleague. I had been amazed by how quickly he
> came up to speed on complex aspects of Visual. I'll miss him.
>
> Bruce Sherwood
>
>
> -------------------------------------------------------------------------
> Using Tomcat but need to do more? Need to support web services, security?
> Get stuff done quickly with pre-integrated technology to make your job
> easier.
> Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo
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> _______________________________________________
> Visualpython-users mailing list
> Vis...@li...
> https://lists.sourceforge.net/lists/listinfo/visualpython-users
>



-- 
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Jon Schull, Ph.D.
Associate Professor
Information Technology
Rochester Institute of Technology
102 Lomb Memorial Drive
Rochester, New York 14623
sc...@di... 585-738-6696

[Visualpython-users] Arthur Siegel

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

 From the New York Time obituaries:

Arthur Jay Siegel  	 	
SIEGEL - Arthur Jay , 55, died Tuesday evening of an unexpected heart 
attack. An international business consultant and a self-taught 
mathematician/computer scientist, he invented PyGeo - a software used to 
create interactive, three-dimensional geometric spaces. He grew up in 
East Meadow. He and his loving wife of 29 years, Carol, moved four years 
ago to Yorktown Heights. He treasured a close friendship with his son, 
Benjamin, 23. In addition to Ben and Carol, Arthur is survived by his 
father, Jacob Siegel, sisters Beth Siegel, Marian Siegel and Marsha 
Berzon and many loving nieces, nephews, cousins, in-laws and friends. 
Funeral services will be held at Riverside Memorial Chapel, 21 W. Broad 
Street, Mount Vernon, New York at noon on Sunday.

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

I'm thunderstruck by this bolt out of the blue. As you know, Arthur was 
doing wonderful work on the beta version of VPython. I never met him in 
person, but he was a good colleague. I had been amazed by how quickly he 
came up to speed on complex aspects of Visual. I'll miss him.

Bruce Sherwood

[Visualpython-users] VPython Video

[Joel K. <jj...@ya...>]

A site to look at:

http://www.current.tv/watch/21639966

As I indicated in the description, VPython was
used to generate the video. I captured the 
animation with CamStudio, which co-operates
fairly well with VPython at low resolutions
(this was 320x240), but which can run into 
some problems if the rez gets too high.

Environments like Current might be good places 
for students to experiment with digital videos
made from VPython. Since Current (and certain
similar sites) pay for videos that they use,
there may also be some fund-raising potential.

Feel free to register with Current and greenlight
my video; if *I* get paid enough for VPython-based
work, it will enable me to spend more time on it
and make a greater contribution to its progress. :-)

Spread the word. . . .

Joel



 
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Re: [Visualpython-users] how to rotate a frame inside a class?

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

Sorry, but I don't understand what it is you're asking about. I don't=20
see any rotation being carried out. Please tell us in some detail what=20
it is you're trying to do, and what you think isn't working properly. It=20
would help a lot to simplify your example to its essence, just enough to=20
demonstrate the problem, without extraneous features.

Bruce Sherwood

Stefan Paulick wrote:
> When rotating a frame inside a class, it starts to move and rotates aro=
und=20
> some mysterious center.
> I could not find out how to calculate origin for a propper offset.=20
>
> Please find attached my example. I would be glad for any hint.=20
>
> Thanks in advance,=20
>
> Mit freundlichen Gr=FC=DFen / With kindest regards=20
>
> Stefan Paulick=20
>
>
> http://www.urbeli.com
> mailto://ste...@ur...
> /*----------------------*/=20
>
> import time
> import visual=20
>
> b =3D visual.box(height =3D .1)
> c =3D visual.cylinder(pos=3D(2,2,2),axis=3D(2,0,0),radius=3D.1)
> f =3D visual.frame()
> d =3D visual.cylinder(frame=3Df,pos=3D(1,2,1),axis=3D(2,0,0),radius=3D.=
1)
> e =3D visual.cylinder(pos=3D(0,0,0),axis=3D(2,0,0),radius=3D.1)
> e.pos =3D (3,2,3)=20
>
> class cC():
>    def __init__(self, pos=3D(0,0,0), axis=3D(2,0,0)):
>        self.pos =3D visual.vector(pos)
>        self.axis =3D visual.vector(axis)
>        self.f =3D visual.frame()
>        self.g =3D=20
> visual.cylinder(frame=3Df,pos=3Dself.pos,axis=3Dself.axis,radius=3D.1)
>        self.g.pos =3D visual.vector(0,2,0)
>
>    def wpos(self,local):
>        x_axis =3D visual.norm(f.axis)
>        z_axis =3D visual.norm(visual.cross(f.axis, f.up))
>        y_axis =3D visual.norm(visual.cross(z_axis, x_axis))
>        #return  x_axis,y_axis,z_axis
>        return self.f.pos+local[0]*x_axis+local[1]*y_axis+local[2]*z_axi=
s
>
> u =3D cC()=20
>
> ax =3D 0
> cnt =3D 0.=20
>
> while 1:
>    print u.wpos((1,2,0))
>
>    if ax =3D=3D 0:
>        c.rotate(angle=3D.15, axis=3D(0,1,0), origin=3D(3,2,2))
>        f.rotate(angle=3D.15, axis=3D(0,1,0), origin=3D(2,2,1))
>        e.rotate(angle=3D.15, axis=3D(0,1,0), origin=3D(4,2,3))
>        u.f.rotate(angle=3D.15, axis=3D(0,1,0), origin=3D(1,2,0))=20
>
>        c.color =3D (1,1,0)
>    elif ax =3D=3D 1:
>        c.rotate(angle=3D.15, axis=3D(0,0,1), origin=3D(3,2,2))
>        f.rotate(angle=3D.15, axis=3D(0,0,1), origin=3D(2,2,1))
>        e.rotate(angle=3D.15, axis=3D(0,0,1), origin=3D(4,2,3))
>        u.f.rotate(angle=3D.15, axis=3D(0,0,1), origin=3D(1,2,0))
>        c.color =3D (1,0,0)
>    elif ax =3D=3D 2:
>        c.rotate(angle=3D.15, axis=3D(1,0,0), origin=3D(3,2,2))
>        f.rotate(angle=3D.15, axis=3D(1,0,0), origin=3D(2,2,1))
>        e.rotate(angle=3D.15, axis=3D(1,0,0), origin=3D(4,2,3))
>        u.f.rotate(angle=3D.15, axis=3D(1,0,0), origin=3D(1,2,0))
>        c.color =3D (0,0,1)=20
>
>    cnt +=3D1
>    ## print cnt,ax
>    if cnt > 10:
>        cnt =3D 0
>        ax +=3D 1
>        if ax > 2:
>            ax =3D 0
>    time.sleep(.1)
>
> -----------------------------------------------------------------------=
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> Using Tomcat but need to do more? Need to support web services, securit=
y?
> Get stuff done quickly with pre-integrated technology to make your job =
easier.
> Download IBM WebSphere Application Server v.1.0.1 based on Apache Geron=
imo
> http://sel.as-us.falkag.net/sel?cmd=3Dlnk&kid=3D120709&bid=3D263057&dat=
=3D121642
> _______________________________________________
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> https://lists.sourceforge.net/lists/listinfo/visualpython-users
>  =20

[Visualpython-users] how to rotate a frame inside a class?

[Stefan P. <ste...@ur...>]

When rotating a frame inside a class, it starts to move and rotates around 
some mysterious center.
I could not find out how to calculate origin for a propper offset. 

Please find attached my example. I would be glad for any hint. 

Thanks in advance, 

Mit freundlichen Grüßen / With kindest regards 

Stefan Paulick 


http://www.urbeli.com
mailto://ste...@ur...
/*----------------------*/ 

import time
import visual 

b = visual.box(height = .1)
c = visual.cylinder(pos=(2,2,2),axis=(2,0,0),radius=.1)
f = visual.frame()
d = visual.cylinder(frame=f,pos=(1,2,1),axis=(2,0,0),radius=.1)
e = visual.cylinder(pos=(0,0,0),axis=(2,0,0),radius=.1)
e.pos = (3,2,3) 

class cC():
   def __init__(self, pos=(0,0,0), axis=(2,0,0)):
       self.pos = visual.vector(pos)
       self.axis = visual.vector(axis)
       self.f = visual.frame()
       self.g = 
visual.cylinder(frame=f,pos=self.pos,axis=self.axis,radius=.1)
       self.g.pos = visual.vector(0,2,0)

   def wpos(self,local):
       x_axis = visual.norm(f.axis)
       z_axis = visual.norm(visual.cross(f.axis, f.up))
       y_axis = visual.norm(visual.cross(z_axis, x_axis))
       #return  x_axis,y_axis,z_axis
       return self.f.pos+local[0]*x_axis+local[1]*y_axis+local[2]*z_axis

u = cC() 

ax = 0
cnt = 0. 

while 1:
   print u.wpos((1,2,0))

   if ax == 0:
       c.rotate(angle=.15, axis=(0,1,0), origin=(3,2,2))
       f.rotate(angle=.15, axis=(0,1,0), origin=(2,2,1))
       e.rotate(angle=.15, axis=(0,1,0), origin=(4,2,3))
       u.f.rotate(angle=.15, axis=(0,1,0), origin=(1,2,0)) 

       c.color = (1,1,0)
   elif ax == 1:
       c.rotate(angle=.15, axis=(0,0,1), origin=(3,2,2))
       f.rotate(angle=.15, axis=(0,0,1), origin=(2,2,1))
       e.rotate(angle=.15, axis=(0,0,1), origin=(4,2,3))
       u.f.rotate(angle=.15, axis=(0,0,1), origin=(1,2,0))
       c.color = (1,0,0)
   elif ax == 2:
       c.rotate(angle=.15, axis=(1,0,0), origin=(3,2,2))
       f.rotate(angle=.15, axis=(1,0,0), origin=(2,2,1))
       e.rotate(angle=.15, axis=(1,0,0), origin=(4,2,3))
       u.f.rotate(angle=.15, axis=(1,0,0), origin=(1,2,0))
       c.color = (0,0,1) 

   cnt +=1
   ## print cnt,ax
   if cnt > 10:
       cnt = 0
       ax += 1
       if ax > 2:
           ax = 0
   time.sleep(.1)

Re: [Visualpython-users] [Matplotlib-users] segfault when running with pylab

[Mark H. <ma...@mi...>]

Self follow-up:
Rolled back to visual 0.3.2.9 and the segfault with pylab is not present 
there; both the visual object and pylab graph are rendered correctly. 
Sorry vpython, looks like the bug is due to your new beta.

-Mark

Mark Heslep wrote:
> Version information:
> ---------------------------
> Vpython visual-4.beta14
> In [2]: visual.__version__
> Out[2]: '1.0.1'
> Python 2.4.4, Fedora Core 6 updated.
> python-matplotlib-0.87.7-3.fc6
>
> Description:
> A segfault is reliably produced when running vpython along with pylab / 
> matplotlib functions:
>
> cut------------------------------------------
> from visual import *
> from pylab import *
>
> ball = sphere( pos=(0,0,0), color=color.red)
> x=arrange(0,10,0.1)
> y=sin(2*pi*x)
> plot(x,y)
> cut ------------------------------------------
>
>
> The segfault actually triggers on the plot call, but removing _either_ 
> the visual sphere call _or_ the pylab plot call eliminates the segfault, 
> with the either the plot or the ball rendering correctly.
> Ive filed a bug w/ vpython.  Any ideas?
>
> Regards,
> Mark
>
>
> -------------------------------------------------------------------------
> Using Tomcat but need to do more? Need to support web services, security?
> Get stuff done quickly with pre-integrated technology to make your job easier.
> Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo
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> _______________________________________________
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> Mat...@li...
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>
>   

[Visualpython-users] segfault when running with pylab

[Mark H. <ma...@mi...>]

Version information:
---------------------------
Vpython visual-4.beta14
In [2]: visual.__version__
Out[2]: '1.0.1'
Python 2.4.4, Fedora Core 6 updated.
python-matplotlib-0.87.7-3.fc6

Description:
A segfault is reliably produced when running vpython along with pylab / 
matplotlib functions:

cut------------------------------------------
from visual import *
from pylab import *

ball = sphere( pos=(0,0,0), color=color.red)
x=arrange(0,10,0.1)
y=sin(2*pi*x)
plot(x,y)
cut ------------------------------------------


The segfault actually triggers on the plot call, but removing _either_ 
the visual sphere call _or_ the pylab plot call eliminates the segfault, 
with the either the plot or the ball rendering correctly.
Ive filed a bug w/ vpython.  Any ideas?

Regards,
Mark

[Visualpython-users] Pickling Visual python objects.

[Chris L. <chr...@sp...>]

I'm trying to find a flexible way of storing visual objects in a 
database. I had considered building a set of schema's to describe the 
objects but a desire to store other parameters along with the visual 
objects made me feel that might not be as maintainable as I might like 
so I thought of pickling visual objects and saving the serialized output.
Upon trying this I get:

Traceback (most recent call last):
   File "<pyshell#36>", line 1, in <module>
     pickle.dump(data, output)
   File "C:\Python25\lib\pickle.py", line 1362, in dump
     Pickler(file, protocol).dump(obj)
   File "C:\Python25\lib\pickle.py", line 224, in dump
     self.save(obj)
   File "C:\Python25\lib\pickle.py", line 286, in save
     f(self, obj) # Call unbound method with explicit self
   File "C:\Python25\lib\pickle.py", line 562, in save_tuple
     save(element)
   File "C:\Python25\lib\pickle.py", line 331, in save
     self.save_reduce(obj=obj, *rv)
   File "C:\Python25\lib\pickle.py", line 401, in save_reduce
     save(args)
   File "C:\Python25\lib\pickle.py", line 286, in save
     f(self, obj) # Call unbound method with explicit self
   File "C:\Python25\lib\pickle.py", line 562, in save_tuple
     save(element)
   File "C:\Python25\lib\pickle.py", line 295, in save
     self.save_global(obj)
   File "C:\Python25\lib\pickle.py", line 748, in save_global
     (obj, module, name))
PicklingError: Can't pickle <type 'Boost.Python.instance'>: it's not 
found as Boost.Python.instance
 >>>

Is this a non starter or might it be worthwhile to strip out the 
parameters of a visual object and repopulate the object upon pickle.load()?

Re: [Visualpython-users] Movie of VPython animations

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

See discussion in the FAQ at vpython.org.

Bruce Sherwood

Chandra Prayaga wrote:
> Is it possible to capture a VPython animation as a movie, or is there a method of putting the animation on the web?
>  
> Chandra Prayaga
> Physics department
> University of West Florida
> cpr...@uw...
>  
>  
> 
> -------------------------------------------------------------------------
> Take Surveys. Earn Cash. Influence the Future of IT
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[Visualpython-users] Movie of VPython animations

[Chandra P. <cpr...@uw...>]

Is it possible to capture a VPython animation as a movie, or is there a =
method of putting the animation on the web?
=20
Chandra Prayaga
Physics department
University of West Florida
cpr...@uw...
=20
=20

Re: [Visualpython-users] how to draw lines, 2D and 3D

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

See the curve object; just give starting and ending locations to draw a 
line.

Bruce Sherwood

siggi wrote:
> Hi all,
>
> I am a complete newbie to VPython, but I got hooked. I
> tried the bouncing ball, enriched it with audio from
> Pygame, and the simple function plot; so little code,
> so great
> effects!
>
> My first problem: how do I draw a line from x to y? I
> know how to plot functions with VPython, such as
> x = f(x), see above
>
> but how do I plot a 2D function such as
> x = f1(x)
> y = f2(y)
> draw line between x and y?
>
> In Python it is done, e.g., like this
>
>     while theta < 75.39:
>       r = math.exp(math.cos(theta))-
>         2*math.cos(4*theta)+(math.sin(theta/12))**5
>      # convert from polar coordinates
>       x = r*math.cos(theta)
>       y = r*math.sin(theta)
>       # scale to canvas size
>       xx = (x*30) + 150
>       yy = (y*30) + 150
>       if (theta == 0.0):
>         Canvas.Line(self.canvas, xx, yy, xx, yy)
>       else:
>         Canvas.Line(self.canvas, xOld, yOld, xx, yy)
>       self.canvas.update_idletasks()
>       xOld = xx
>       yOld = yy
>       theta = theta + 0.02
>
> which, in this case, creates a butterfly curve
> (from http://www.pythonmania.de/article/pybutt.html)
>
> Unfortunately, browsing tutorials and documents on
> www.vpython.org, I could not find a "line " command.
> If there would be one, 3D "butterfly" curves
> would be possible, too.
>
> Thanks,
>
> siggi
>
>
>
>
>
>  
> ____________________________________________________________________________________
> Any questions? Get answers on any topic at www.Answers.yahoo.com.  Try it now.
>
> -------------------------------------------------------------------------
> Take Surveys. Earn Cash. Influence the Future of IT
> Join SourceForge.net's Techsay panel and you'll get the chance to share your
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>   

[Visualpython-users] how to draw lines, 2D and 3D

[siggi <sm...@ya...>]

Hi all,

I am a complete newbie to VPython, but I got hooked. I
tried the bouncing ball, enriched it with audio from
Pygame, and the simple function plot; so little code,
so great
effects!

My first problem: how do I draw a line from x to y? I
know how to plot functions with VPython, such as
x = f(x), see above

but how do I plot a 2D function such as
x = f1(x)
y = f2(y)
draw line between x and y?

In Python it is done, e.g., like this

    while theta < 75.39:
      r = math.exp(math.cos(theta))-
        2*math.cos(4*theta)+(math.sin(theta/12))**5
     # convert from polar coordinates
      x = r*math.cos(theta)
      y = r*math.sin(theta)
      # scale to canvas size
      xx = (x*30) + 150
      yy = (y*30) + 150
      if (theta == 0.0):
        Canvas.Line(self.canvas, xx, yy, xx, yy)
      else:
        Canvas.Line(self.canvas, xOld, yOld, xx, yy)
      self.canvas.update_idletasks()
      xOld = xx
      yOld = yy
      theta = theta + 0.02

which, in this case, creates a butterfly curve
(from http://www.pythonmania.de/article/pybutt.html)

Unfortunately, browsing tutorials and documents on
www.vpython.org, I could not find a "line " command.
If there would be one, 3D "butterfly" curves
would be possible, too.

Thanks,

siggi





 
____________________________________________________________________________________
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Re: [Visualpython-users] VPython render efficiency

[Jonathan B. <jbr...@ea...>]

On Thu, 2007-01-25 at 12:53 +0100, Ting Li wrote:
> Hi, fans,
> 
> I'm a newbie.
> 
> VPython is really easy to use. But it looks too simple.
> I wonder if there is a parameter to customize the number of faces used
> to draw a sphere (or cylinder ...)? I cannot find it. By default,
> VPython draws a pretty smooth sphere, I guess the number of slice
> should be larger than 50.
> 
> Sphere(pos=(*,*,*),color=color.red)
> 
> However, low polygon objects are needed. This control is necessary to
> make smooth animation, especially when the number of objects is large.
> 
> I know VPython gives a way to build object by user, face.
> But can the authors make life easier?
> 
> Another question is also about the rendering efficiency.
> I don't know if VPython uses gllist internally.

VPython 4 uses GL displaylists, whereas 3.x uses vertex arrays (still
fairly fast).

>  (sorry, haven't
> studied the source) ,and if VPython support object 'instance'? (A
> instance of an object doesn't need to rebuild the vertex array at a
> new position but just copy the vertex from the original object and
> perform translation, scale, or zoom. )

Where possible, objects share the same geometry to conserve memory and
for speed.  Objects with instance-specific geometry include arrow, ring,
curve, convex, points, and faces.

-Jonathan