visualpython-users

[Visualpython-users] "import random" Odd Behavior on OSX install VPython v.3.1

[Eric D. <mon...@ma...>]

Hello,

I recently installed the VPython v.3.1 and corresponding Python versions for mac (OSX).  I've been troubleshooting an old script of mine when I noticed some odd behavior.

When I run my script, a line tries to import random.  Oddly the shell reports that its using a file from numpy rather than from ~/python3.1/random.py.  If I try to import random  manually in the shell it grabs the correct module from ~/python3.1/random.py.

A. Python Shell
>>> import random
>>> print (random.__file__)
/Library/Frameworks/Python.framework/Versions/3.1/lib/python3.1/random.py

B. Script File 
>>> print (random.__file__)
/Library/Frameworks/Python.framework/Versions/3.1/lib/python3.1/site-packages/numpy/random/__init__.py

Does anyone know how to fix this?  Also does anyone know what is going on?

Please reply with complete instructions, as I am very very very new to all of this.

Thank you all in advance!

Re: [Visualpython-users] getting version info

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

from visual import *
print(version)

Also, for recent versions of VPython, the main page of the help shows
the version number.

Bruce Sherwood

On Sun, May 22, 2011 at 7:17 PM, Dan Aldrich <dal...@ea...> wrote:
> I'm getting ready to move up/on to python 3 this summer. Is there a
> way to get vPython version info like you can w/ python?
>
>        import sys
>        print sys.version_info
>
> Thanks,
> -d
>
>
>
> ------------------------------------------------------------------------------
> What Every C/C++ and Fortran developer Should Know!
> Read this article and learn how Intel has extended the reach of its
> next-generation tools to help Windows* and Linux* C/C++ and Fortran
> developers boost performance applications - including clusters.
> http://p.sf.net/sfu/intel-dev2devmay
> _______________________________________________
> Visualpython-users mailing list
> Vis...@li...
> https://lists.sourceforge.net/lists/listinfo/visualpython-users
>

[Visualpython-users] getting version info

[Dan A. <dal...@ea...>]

I'm getting ready to move up/on to python 3 this summer. Is there a 
way to get vPython version info like you can w/ python?

	import sys
	print sys.version_info

Thanks,
-d

Re: [Visualpython-users] povexport of vpython materials

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

Great! We'll take a look. Thanks.

Bruce Sherwood

On Wed, May 18, 2011 at 8:04 AM, Jasper Stolte <jas...@gm...> wrote:
> Ok, I had some time just now, so I added the finish and color tags and put
> in an extra example file which shows how to use them. Please see if you
> think this is useful. It still doesn't do materials, interiors, subplanes
> and other things I stumbled across in the pov help. But already I think this
> helps in making renderings of the most common materials.
>
> Kind regards,
> Jasper
>
>
> On Wed, May 18, 2011 at 11:07 AM, Jasper Stolte <jas...@gm...>
> wrote:
>>
>> Absolutely, it's fairly straight forward to add a pov_finish and pov_color
>> tags in a way similar to the pov_texture. I can add those easily enough.
>> It'll add to the code repetition in all the export_ functions though. I
>> think some code refactoring would make the module cleaner, more transparent.
>> But who has the time for that, right?
>>
>> Jasper
>>
>>
>> On Wed, May 18, 2011 at 4:20 AM, Bruce Sherwood <Bru...@nc...>
>> wrote:
>>>
>>> No, you're probably not missing anything. I'll comment that Ruth
>>> Chabay is currently deeply involved in an unrelated project, so it's
>>> not clear when she will work on updating povexport. Moreover, her main
>>> priorities are just dealing with the objects currently not supported,
>>> especially faces, text, and extrusion.
>>>
>>> Note however that povexport is not a very large program, and written
>>> in pure Python, so if you have a clear vision of how it should be
>>> improved to deal with the attributes of interest to you, I encourage
>>> you to consider improving povexport yourself.
>>>
>>> Bruce Sherwood
>>>
>>> On Mon, May 16, 2011 at 5:16 AM, Jasper Stolte <jas...@gm...>
>>> wrote:
>>> > Bruce, thank you for your prompt reply.
>>> >
>>> > Indeed, I noticed the support for (among others) woods and metals
>>> > through
>>> > the .inc files. However, I believe these materials are purely texture
>>> > based.
>>> > It seems to me povexport only does pov_texture, as I cannot find
>>> > something
>>> > for pov_finish or pov_color. For example, it is not quite clear to me
>>> > why we
>>> > would include colors.inc, since I dont think you can use its color
>>> > definitions through the pov_texture variable anyway. Similarly, as far
>>> > as I
>>> > can see, from the metals.inc only the textures can be used, not the
>>> > colors
>>> > or the finishes. The wood example only works because wood only requires
>>> > texture, and no finish or color. There is no example that uses the
>>> > colors/finishes from the metals.inc or colors.inc macros, and as far as
>>> > I
>>> > can see they cannot be used without modifying povexport to support them
>>> > first.
>>> >
>>> > Or maybe I am just completely missing something.. :)
>>> > Kind regards,
>>> >
>>> > Jasper
>>> >
>>> >
>>> > On Sun, May 15, 2011 at 10:27 PM, Bruce Sherwood
>>> > <Bru...@nc...>
>>> > wrote:
>>> >>
>>> >> There is some support for materials, as indicated in the header to the
>>> >> 2009 version of povexport, available in the contributed section of
>>> >> vpython.org:
>>> >>
>>> >> This module exports a VPython scene as POV-Ray scene description code.
>>> >> Lights and camera location from the current visual scene are included.
>>> >> Optionally, you may specify a list of include files,
>>> >>   and pov textures for objects.
>>> >> For an example of its use, see 'povexample.py'.
>>> >> Currently convex, faces, and points objects are not exported.
>>> >> Further documentation is found at the start of the file.
>>> >>
>>> >> Also see the example program povexample_wood.py, which is included in
>>> >> the 2009 povexport package.
>>> >>
>>> >> The relatively recent objects "text" and "extrusion" are not handled
>>> >> by povexport. Ruth Chabay, the originator of povexport, intends to
>>> >> bring povexport up to date. The "create_faces()" method for extrusion
>>> >> objects was created to make it feasible to export an extrusion to
>>> >> povexport (and the text object creates an extrusion, so it too should
>>> >> prove to be exportable).
>>> >>
>>> >> Bruce Sherwood
>>> >>
>>> >> On Sun, May 15, 2011 at 6:28 AM, Jasper Stolte
>>> >> <jas...@gm...>
>>> >> wrote:
>>> >> > Hi guys,
>>> >> >
>>> >> > It's been a few years since I used vpython, but I'm happy to see
>>> >> > there
>>> >> > is
>>> >> > still activity and development of this useful tool. For my new
>>> >> > project
>>> >> > I'm
>>> >> > using povexport, which exports the scenes nicely into pov-ray
>>> >> > format.
>>> >> > However when I look at the resulting pictures the material
>>> >> > information
>>> >> > seems
>>> >> > lost. Everything ends up looking like I selected materials.diffuse
>>> >> > for
>>> >> > it.
>>> >> >
>>> >> > Digging into the documentation I found that pov-ray uses a 'finish'
>>> >> > tag
>>> >> > to
>>> >> > specify things such as reflectivity etc. Tweaking the finish tag
>>> >> > parameters
>>> >> > manually I quickly rendered something which was looking at least
>>> >> > acceptable.
>>> >> > Now my question is whether you guys have experience mapping the
>>> >> > vpython
>>> >> > materials to the pov-ray finish tag, and if you would be willing to
>>> >> > share
>>> >> > parameters? Maybe someone has even started improving the povexport
>>> >> > module to
>>> >> > include the finish tag?
>>> >> >
>>> >> > Kind regards,
>>> >> > Jasper

Re: [Visualpython-users] povexport of vpython materials

[Jasper S. <jas...@gm...>]

Absolutely, it's fairly straight forward to add a pov_finish and pov_color
tags in a way similar to the pov_texture. I can add those easily enough.
It'll add to the code repetition in all the export_ functions though. I
think some code refactoring would make the module cleaner, more transparent.
But who has the time for that, right?

Jasper


On Wed, May 18, 2011 at 4:20 AM, Bruce Sherwood <Bru...@nc...>wrote:

> No, you're probably not missing anything. I'll comment that Ruth
> Chabay is currently deeply involved in an unrelated project, so it's
> not clear when she will work on updating povexport. Moreover, her main
> priorities are just dealing with the objects currently not supported,
> especially faces, text, and extrusion.
>
> Note however that povexport is not a very large program, and written
> in pure Python, so if you have a clear vision of how it should be
> improved to deal with the attributes of interest to you, I encourage
> you to consider improving povexport yourself.
>
> Bruce Sherwood
>
> On Mon, May 16, 2011 at 5:16 AM, Jasper Stolte <jas...@gm...>
> wrote:
> > Bruce, thank you for your prompt reply.
> >
> > Indeed, I noticed the support for (among others) woods and metals through
> > the .inc files. However, I believe these materials are purely texture
> based.
> > It seems to me povexport only does pov_texture, as I cannot find
> something
> > for pov_finish or pov_color. For example, it is not quite clear to me why
> we
> > would include colors.inc, since I dont think you can use its color
> > definitions through the pov_texture variable anyway. Similarly, as far as
> I
> > can see, from the metals.inc only the textures can be used, not the
> colors
> > or the finishes. The wood example only works because wood only requires
> > texture, and no finish or color. There is no example that uses the
> > colors/finishes from the metals.inc or colors.inc macros, and as far as I
> > can see they cannot be used without modifying povexport to support them
> > first.
> >
> > Or maybe I am just completely missing something.. :)
> > Kind regards,
> >
> > Jasper
> >
> >
> > On Sun, May 15, 2011 at 10:27 PM, Bruce Sherwood <
> Bru...@nc...>
> > wrote:
> >>
> >> There is some support for materials, as indicated in the header to the
> >> 2009 version of povexport, available in the contributed section of
> >> vpython.org:
> >>
> >> This module exports a VPython scene as POV-Ray scene description code.
> >> Lights and camera location from the current visual scene are included.
> >> Optionally, you may specify a list of include files,
> >>   and pov textures for objects.
> >> For an example of its use, see 'povexample.py'.
> >> Currently convex, faces, and points objects are not exported.
> >> Further documentation is found at the start of the file.
> >>
> >> Also see the example program povexample_wood.py, which is included in
> >> the 2009 povexport package.
> >>
> >> The relatively recent objects "text" and "extrusion" are not handled
> >> by povexport. Ruth Chabay, the originator of povexport, intends to
> >> bring povexport up to date. The "create_faces()" method for extrusion
> >> objects was created to make it feasible to export an extrusion to
> >> povexport (and the text object creates an extrusion, so it too should
> >> prove to be exportable).
> >>
> >> Bruce Sherwood
> >>
> >> On Sun, May 15, 2011 at 6:28 AM, Jasper Stolte <jas...@gm...>
> >> wrote:
> >> > Hi guys,
> >> >
> >> > It's been a few years since I used vpython, but I'm happy to see there
> >> > is
> >> > still activity and development of this useful tool. For my new project
> >> > I'm
> >> > using povexport, which exports the scenes nicely into pov-ray format.
> >> > However when I look at the resulting pictures the material information
> >> > seems
> >> > lost. Everything ends up looking like I selected materials.diffuse for
> >> > it.
> >> >
> >> > Digging into the documentation I found that pov-ray uses a 'finish'
> tag
> >> > to
> >> > specify things such as reflectivity etc. Tweaking the finish tag
> >> > parameters
> >> > manually I quickly rendered something which was looking at least
> >> > acceptable.
> >> > Now my question is whether you guys have experience mapping the
> vpython
> >> > materials to the pov-ray finish tag, and if you would be willing to
> >> > share
> >> > parameters? Maybe someone has even started improving the povexport
> >> > module to
> >> > include the finish tag?
> >> >
> >> > Kind regards,
> >> > Jasper
> >>
>
>
> ------------------------------------------------------------------------------
> What Every C/C++ and Fortran developer Should Know!
> Read this article and learn how Intel has extended the reach of its
> next-generation tools to help Windows* and Linux* C/C++ and Fortran
> developers boost performance applications - including clusters.
> http://p.sf.net/sfu/intel-dev2devmay
> _______________________________________________
> Visualpython-users mailing list
> Vis...@li...
> https://lists.sourceforge.net/lists/listinfo/visualpython-users
>

Re: [Visualpython-users] povexport of vpython materials

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

No, you're probably not missing anything. I'll comment that Ruth
Chabay is currently deeply involved in an unrelated project, so it's
not clear when she will work on updating povexport. Moreover, her main
priorities are just dealing with the objects currently not supported,
especially faces, text, and extrusion.

Note however that povexport is not a very large program, and written
in pure Python, so if you have a clear vision of how it should be
improved to deal with the attributes of interest to you, I encourage
you to consider improving povexport yourself.

Bruce Sherwood

On Mon, May 16, 2011 at 5:16 AM, Jasper Stolte <jas...@gm...> wrote:
> Bruce, thank you for your prompt reply.
>
> Indeed, I noticed the support for (among others) woods and metals through
> the .inc files. However, I believe these materials are purely texture based.
> It seems to me povexport only does pov_texture, as I cannot find something
> for pov_finish or pov_color. For example, it is not quite clear to me why we
> would include colors.inc, since I dont think you can use its color
> definitions through the pov_texture variable anyway. Similarly, as far as I
> can see, from the metals.inc only the textures can be used, not the colors
> or the finishes. The wood example only works because wood only requires
> texture, and no finish or color. There is no example that uses the
> colors/finishes from the metals.inc or colors.inc macros, and as far as I
> can see they cannot be used without modifying povexport to support them
> first.
>
> Or maybe I am just completely missing something.. :)
> Kind regards,
>
> Jasper
>
>
> On Sun, May 15, 2011 at 10:27 PM, Bruce Sherwood <Bru...@nc...>
> wrote:
>>
>> There is some support for materials, as indicated in the header to the
>> 2009 version of povexport, available in the contributed section of
>> vpython.org:
>>
>> This module exports a VPython scene as POV-Ray scene description code.
>> Lights and camera location from the current visual scene are included.
>> Optionally, you may specify a list of include files,
>>   and pov textures for objects.
>> For an example of its use, see 'povexample.py'.
>> Currently convex, faces, and points objects are not exported.
>> Further documentation is found at the start of the file.
>>
>> Also see the example program povexample_wood.py, which is included in
>> the 2009 povexport package.
>>
>> The relatively recent objects "text" and "extrusion" are not handled
>> by povexport. Ruth Chabay, the originator of povexport, intends to
>> bring povexport up to date. The "create_faces()" method for extrusion
>> objects was created to make it feasible to export an extrusion to
>> povexport (and the text object creates an extrusion, so it too should
>> prove to be exportable).
>>
>> Bruce Sherwood
>>
>> On Sun, May 15, 2011 at 6:28 AM, Jasper Stolte <jas...@gm...>
>> wrote:
>> > Hi guys,
>> >
>> > It's been a few years since I used vpython, but I'm happy to see there
>> > is
>> > still activity and development of this useful tool. For my new project
>> > I'm
>> > using povexport, which exports the scenes nicely into pov-ray format.
>> > However when I look at the resulting pictures the material information
>> > seems
>> > lost. Everything ends up looking like I selected materials.diffuse for
>> > it.
>> >
>> > Digging into the documentation I found that pov-ray uses a 'finish' tag
>> > to
>> > specify things such as reflectivity etc. Tweaking the finish tag
>> > parameters
>> > manually I quickly rendered something which was looking at least
>> > acceptable.
>> > Now my question is whether you guys have experience mapping the vpython
>> > materials to the pov-ray finish tag, and if you would be willing to
>> > share
>> > parameters? Maybe someone has even started improving the povexport
>> > module to
>> > include the finish tag?
>> >
>> > Kind regards,
>> > Jasper
>>

Re: [Visualpython-users] povexport of vpython materials

[Jasper S. <jas...@gm...>]

Bruce, thank you for your prompt reply.

Indeed, I noticed the support for (among others) woods and metals through
the .inc files. However, I believe these materials are purely texture based.
It seems to me povexport only does pov_texture, as I cannot find something
for pov_finish or pov_color. For example, it is not quite clear to me why we
would include colors.inc, since I dont think you can use its color
definitions through the pov_texture variable anyway. Similarly, as far as I
can see, from the metals.inc only the textures can be used, not the colors
or the finishes. The wood example only works because wood only requires
texture, and no finish or color. There is no example that uses the
colors/finishes from the metals.inc or colors.inc macros, and as far as I
can see they cannot be used without modifying povexport to support them
first.

Or maybe I am just completely missing something.. :)
Kind regards,

Jasper


On Sun, May 15, 2011 at 10:27 PM, Bruce Sherwood <Bru...@nc...>wrote:

> There is some support for materials, as indicated in the header to the
> 2009 version of povexport, available in the contributed section of
> vpython.org:
>
> This module exports a VPython scene as POV-Ray scene description code.
> Lights and camera location from the current visual scene are included.
> Optionally, you may specify a list of include files,
>   and pov textures for objects.
> For an example of its use, see 'povexample.py'.
> Currently convex, faces, and points objects are not exported.
> Further documentation is found at the start of the file.
>
> Also see the example program povexample_wood.py, which is included in
> the 2009 povexport package.
>
> The relatively recent objects "text" and "extrusion" are not handled
> by povexport. Ruth Chabay, the originator of povexport, intends to
> bring povexport up to date. The "create_faces()" method for extrusion
> objects was created to make it feasible to export an extrusion to
> povexport (and the text object creates an extrusion, so it too should
> prove to be exportable).
>
> Bruce Sherwood
>
> On Sun, May 15, 2011 at 6:28 AM, Jasper Stolte <jas...@gm...>
> wrote:
> > Hi guys,
> >
> > It's been a few years since I used vpython, but I'm happy to see there is
> > still activity and development of this useful tool. For my new project
> I'm
> > using povexport, which exports the scenes nicely into pov-ray format.
> > However when I look at the resulting pictures the material information
> seems
> > lost. Everything ends up looking like I selected materials.diffuse for
> it.
> >
> > Digging into the documentation I found that pov-ray uses a 'finish' tag
> to
> > specify things such as reflectivity etc. Tweaking the finish tag
> parameters
> > manually I quickly rendered something which was looking at least
> acceptable.
> > Now my question is whether you guys have experience mapping the vpython
> > materials to the pov-ray finish tag, and if you would be willing to share
> > parameters? Maybe someone has even started improving the povexport module
> to
> > include the finish tag?
> >
> > Kind regards,
> > Jasper
>
>
> ------------------------------------------------------------------------------
> Achieve unprecedented app performance and reliability
> What every C/C++ and Fortran developer should know.
> Learn how Intel has extended the reach of its next-generation tools
> to help boost performance applications - inlcuding clusters.
> http://p.sf.net/sfu/intel-dev2devmay
> _______________________________________________
> Visualpython-users mailing list
> Vis...@li...
> https://lists.sourceforge.net/lists/listinfo/visualpython-users
>

Re: [Visualpython-users] povexport of vpython materials

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

There is some support for materials, as indicated in the header to the
2009 version of povexport, available in the contributed section of
vpython.org:

This module exports a VPython scene as POV-Ray scene description code.
Lights and camera location from the current visual scene are included.
Optionally, you may specify a list of include files,
   and pov textures for objects.
For an example of its use, see 'povexample.py'.
Currently convex, faces, and points objects are not exported.
Further documentation is found at the start of the file.

Also see the example program povexample_wood.py, which is included in
the 2009 povexport package.

The relatively recent objects "text" and "extrusion" are not handled
by povexport. Ruth Chabay, the originator of povexport, intends to
bring povexport up to date. The "create_faces()" method for extrusion
objects was created to make it feasible to export an extrusion to
povexport (and the text object creates an extrusion, so it too should
prove to be exportable).

Bruce Sherwood

On Sun, May 15, 2011 at 6:28 AM, Jasper Stolte <jas...@gm...> wrote:
> Hi guys,
>
> It's been a few years since I used vpython, but I'm happy to see there is
> still activity and development of this useful tool. For my new project I'm
> using povexport, which exports the scenes nicely into pov-ray format.
> However when I look at the resulting pictures the material information seems
> lost. Everything ends up looking like I selected materials.diffuse for it.
>
> Digging into the documentation I found that pov-ray uses a 'finish' tag to
> specify things such as reflectivity etc. Tweaking the finish tag parameters
> manually I quickly rendered something which was looking at least acceptable.
> Now my question is whether you guys have experience mapping the vpython
> materials to the pov-ray finish tag, and if you would be willing to share
> parameters? Maybe someone has even started improving the povexport module to
> include the finish tag?
>
> Kind regards,
> Jasper

[Visualpython-users] povexport of vpython materials

[Jasper S. <jas...@gm...>]

Hi guys,

It's been a few years since I used vpython, but I'm happy to see there is
still activity and development of this useful tool. For my new project I'm
using povexport, which exports the scenes nicely into pov-ray format.
However when I look at the resulting pictures the material information seems
lost. Everything ends up looking like I selected materials.diffuse for it.

Digging into the documentation I found that pov-ray uses a 'finish' tag to
specify things such as reflectivity etc. Tweaking the finish tag parameters
manually I quickly rendered something which was looking at least acceptable.
Now my question is whether you guys have experience mapping the vpython
materials to the pov-ray finish tag, and if you would be willing to share
parameters? Maybe someone has even started improving the povexport module to
include the finish tag?

Kind regards,
Jasper

Re: [Visualpython-users] Segmentation fault on Ubuntu 11.04 !

[M. H. <meg...@ho...>]

Hi Bruce

> Glad to hear you found a solution.
> 
> This isn't the right place to ask about pydy, unless there just
> happens to be someone on this VPython list (not me) who knows
> something about pydy.

Ah, thanks a lot for your help/comments... I'll look somewhere else and figure something out and ask about pydy elsewhere...


> You say you're interested in gears. Starting with VPython 5.50, there
> is an extrusion object and a library of extrudable shapes that
> includes gears. The Ubuntu python-visual package however is version
> 5.12, so you would have to build from source, which can be painful
> (see Linux download page at vpython.org). You can read about
> extrusions and gears in the VPython documentation found at vpython.org
> (and installed with version 5.71).

Ah, ok. Currently I'm a bit too busy to learn something new but maybe I'll get back to that later when I get more time...

Thanks for your help!
 		 	   		  

Re: [Visualpython-users] Segmentation fault on Ubuntu 11.04 !

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

Glad to hear you found a solution.

This isn't the right place to ask about pydy, unless there just
happens to be someone on this VPython list (not me) who knows
something about pydy.

You say you're interested in gears. Starting with VPython 5.50, there
is an extrusion object and a library of extrudable shapes that
includes gears. The Ubuntu python-visual package however is version
5.12, so you would have to build from source, which can be painful
(see Linux download page at vpython.org). You can read about
extrusions and gears in the VPython documentation found at vpython.org
(and installed with version 5.71).

Bruce Sherwood

On Fri, May 6, 2011 at 2:52 AM, M. H. <meg...@ho...> wrote:
>> Googling around, I see lots of notes about people having trouble with
>> proprietary graphics drivers on Ubuntu 11.04. As a test, I tried
>> running the standard OpenGL test program glxgears (which involved
>> installing some mesa components). It should show gears rotating, but
>> in fact the animation hardly ran; the gears mostly didn't move. There
>
> You're absolutely right, thanks.
>
>> is definitely something very wrong in the graphics area of Ubuntu
>> 11.04. This doesn't prove that there isn't some problem with VPython,
>
> Right.
>
>> but there doesn't seem to be much percentage in trying to debug that
>> until and unless basic stuff like glxgears can run properly.
>
> [SOLUTION]
> Ok, problem has been solved: I de-activated using "ATI/AMD proprietary
> FGLRX graphics driver" and re-installed mesa-components, rebooted and
> then glxgears as well as some of the pydy/examples-files runs great!
>
> Both the pendulum examples work great in 3D. However, as an example -
> the "Rolling disc" runs maybe 2-3 frames and stops within 0.5 seconds
> and hangs the window so I have to force quit/close it... I don't have
> any idea about where to locate the cause of this problem...
>
>
> BTW: Now where at least the pendulum examples (single+double) work
> fully in 3D, I'll tell you that I want to learn more about multibody
> modelling. I want to model a gearbox / drivetrain in a windturbine.
> I'm starting to learn from this book: "Computer-Aided Analysis of
> Mechanical Systems" (can be downloaded for free) by Parviz E.
> Nikravesh and thats how I came around pydy... Is pydy suitable
> for that kind of modelling and is it made in a way similar to
> that described by Nikravesh ?
>
> (btw no2: I've now disabled to receive mails in digest mode, because
> I can see that the group forum software doesn't organize my mails
> based on content with the same subject-line... My next replies should
> hopefully be in the correct thread, when I just reply to it instead
> of making a new email everytime)

Re: [Visualpython-users] Segmentation fault on Ubuntu 11.04 !

[M. H. <meg...@ho...>]

> Googling around, I see lots of notes about people having trouble with
> proprietary graphics drivers on Ubuntu 11.04. As a test, I tried
> running the standard OpenGL test program glxgears (which involved
> installing some mesa components). It should show gears rotating, but
> in fact the animation hardly ran; the gears mostly didn't move. There

You're absolutely right, thanks.

> is definitely something very wrong in the graphics area of Ubuntu
> 11.04. This doesn't prove that there isn't some problem with VPython,

Right.

> but there doesn't seem to be much percentage in trying to debug that
> until and unless basic stuff like glxgears can run properly.

[SOLUTION]
Ok, problem has been solved: I de-activated using "ATI/AMD proprietary
FGLRX graphics driver" and re-installed mesa-components, rebooted and
then glxgears as well as some of the pydy/examples-files runs great!

Both the pendulum examples work great in 3D. However, as an example -
the "Rolling disc" runs maybe 2-3 frames and stops within 0.5 seconds
and hangs the window so I have to force quit/close it... I don't have
any idea about where to locate the cause of this problem...


BTW: Now where at least the pendulum examples (single+double) work
fully in 3D, I'll tell you that I want to learn more about multibody
modelling. I want to model a gearbox / drivetrain in a windturbine.
I'm starting to learn from this book: "Computer-Aided Analysis of
Mechanical Systems" (can be downloaded for free) by Parviz E.
Nikravesh and thats how I came around pydy... Is pydy suitable
for that kind of modelling and is it made in a way similar to
that described by Nikravesh ?

(btw no2: I've now disabled to receive mails in digest mode, because
I can see that the group forum software doesn't organize my mails
based on content with the same subject-line... My next replies should
hopefully be in the correct thread, when I just reply to it instead
of making a new email everytime)

 		 	   		  

[Visualpython-users] VPython 5.71: log graphs, offsets in graphs

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

VPython 5.71 adds log-log and semilog plots to graphs, and the ability
to offset the graph origin.

LOG GRAPHS
When creating a gdisplay, you can specify logarithmic plots by
specifying logx=True and/or logy=True. All values must be positive,
representing logarithms of numbers between infinitely small (logarithm
approaches 0) and infinitely large; that is, numbers such as 0.01,
0.1, 1, 10, 100, etc.

GRAPH OFFSETS
If you specify xmin or ymin to be greater than zero, or xmax or ymax
to be less than zero, the crossing point (origin) of the x and y axes
will no longer be at (0,0), and the graphing will be offset. If you
offset the origin of the graph, you must specify xmax to be greater
than xmin, and/or ymax to be greater than ymin.

BUG FIXES
Thanks to a diagnosis by David Scherer, random dots around the text of
label objects (Windows and Linus) are (nearly) eliminated. A bug that
occasionally prevented a graph from displaying has been fixed.

Bruce Sherwood

Re: [Visualpython-users] Segmentation fault on Ubuntu 11.04 !

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

Googling around, I see lots of notes about people having trouble with
proprietary graphics drivers on Ubuntu 11.04. As a test, I tried
running the standard OpenGL test program glxgears (which involved
installing some mesa components). It should show gears rotating, but
in fact the animation hardly ran; the gears mostly didn't move. There
is definitely something very wrong in the graphics area of Ubuntu
11.04. This doesn't prove that there isn't some problem with VPython,
but there doesn't seem to be much percentage in trying to debug that
until and unless basic stuff like glxgears can run properly.

Bruce Sherwood

On Thu, May 5, 2011 at 12:16 PM, Bruce Sherwood <Bru...@nc...> wrote:
> It is the case that VPython worked on Ubuntu 10.10, so downgrading
> would presumably work (or maybe you can boot into 10.10 on the boot
> page). The problem presumably is the video driver. Interesting that
> there's a problem with both you ATI card and my Nvidia card.
>
> I'll mention that the package "python-visual" on Ubuntu 11.04 is still
> VPython 5.12, from August 2009. I wonder whether anyone reading this
> list knows something about how Ubuntu packages are prepared. Seems
> like an awfully long lag time from August 2009 to now, nearly two
> years.
>
> Bruce Sherwood
>
> On Thu, May 5, 2011 at 11:53 AM, M. H. <meg...@ho...> wrote:
>> Hi Bruce Sherwood
>>
>> I'm on Ubuntu 11.04 - I would like to hear if there's an easy fix for this
>> or if other users can verify this problem... Would it help to downgrade or
>> anything?
>

Re: [Visualpython-users] Segmentation fault on Ubuntu 11.04 !

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

It is the case that VPython worked on Ubuntu 10.10, so downgrading
would presumably work (or maybe you can boot into 10.10 on the boot
page). The problem presumably is the video driver. Interesting that
there's a problem with both you ATI card and my Nvidia card.

I'll mention that the package "python-visual" on Ubuntu 11.04 is still
VPython 5.12, from August 2009. I wonder whether anyone reading this
list knows something about how Ubuntu packages are prepared. Seems
like an awfully long lag time from August 2009 to now, nearly two
years.

Bruce Sherwood

On Thu, May 5, 2011 at 11:53 AM, M. H. <meg...@ho...> wrote:
> Hi Bruce Sherwood
>
> I'm on Ubuntu 11.04 - I would like to hear if there's an easy fix for this
> or if other users can verify this problem... Would it help to downgrade or
> anything?

Re: [Visualpython-users] Segmentation fault on Ubuntu 11.04 !

[M. H. <meg...@ho...>]

Hi Bruce Sherwood

I'm on Ubuntu 11.04 - I would like to hear if there's an easy fix for this or if other users can verify this problem... Would it help to downgrade or anything?

 		 	   		  

Re: [Visualpython-users] Segmentation fault on Ubuntu 11.04 !

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

What flavor of Linux are you using?

I'll mention that I just upgraded my Ubuntu installation to 11.04 and
found that VPython has stopped working, with the same failure you see.
My guess is that I have to fight through getting the proprietary
Nvidia drivers re-installed or re-activated or something. Pretty
opaque.

Bruce Sherwood

On Thu, May 5, 2011 at 10:34 AM, M. H. <meg...@ho...> wrote:
> Hi all,
>
> I've downloaded something called "pydy" and it uses Visual Python. I'm not
> too experienced or good at python, however, I think that there's a bug
> somewhere:
>
> $ python
> Python 2.7.1+ (r271:86832, Apr 11 2011, 18:13:53)
> [GCC 4.5.2] on linux2
> Type "help", "copyright", "credits" or "license" for more information.
>>>> from visual import *
>>>> sphere()
> Segmentation fault
>
> I googled a lot and found out that this problem might be due to the graphics
> card. I have an ATI graphics card and am using proprietary drivers in
> Ubuntu...
>
> Please help and suggest...
>

[Visualpython-users] Segmentation fault on Ubuntu 11.04 !

[M. H. <meg...@ho...>]

Hi all,

I've downloaded something called "pydy" and it uses Visual Python. I'm not too experienced or good at python, however, I think that there's a bug somewhere:

$ python
Python 2.7.1+ (r271:86832, Apr 11 2011, 18:13:53) 
[GCC 4.5.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from visual import *
>>> sphere()
Segmentation fault

I googled a lot and found out that this problem might be due to the graphics card. I have an ATI graphics card and am using proprietary drivers in Ubuntu...

Please help and suggest...

 		 	   		  

Re: [Visualpython-users] vPython enhancement

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

A reasonable suggestion. Presumably you've noticed that putting the
cylinder and the cone in a frame let's you move your rounded arrow as
a group just by changing the frame position.

Bruce Sherwood

On Sun, May 1, 2011 at 7:56 AM, Dan Aldrich <dal...@ea...> wrote:
> How about adding a shafttype property to the arrow so it could be
> boxed or round? Right now I'm just drawing a cone at the end of a rod
> and that looks fine so no big deal if it doesn't get added to the wish list.
>
> -d

[Visualpython-users] vPython enhancement

[Dan A. <dal...@ea...>]

How about adding a shafttype property to the arrow so it could be 
boxed or round? Right now I'm just drawing a cone at the end of a rod 
and that looks fine so no big deal if it doesn't get added to the wish list.

-d

Re: [Visualpython-users] Contour lines using vPython

[James M. <mu...@pi...>]

If you want to find and draw the contours yourself, the curve object is an option. If you want to make a contour plot, I would suggest looking at matplotlib

http://matplotlib.sourceforge.net/


On Apr 20, 2011, at 12:09 PM, Bruce Sherwood wrote:

> The curve object will connect a list of points with line segments,
> which sounds like what you want.
> 
> There is a trick to drawing field lines which you might wish to
> implement, to avoid a systematic error. From a starting point where
> you know the field direction, project a line in that direction and
> evaluate the field at a new location on that line. Draw perpendiculars
> to the two vectors and find where those perpendiculars meet (this is
> assuming a 2D field). Imagine that point as the center of a circle,
> and swing a circular arc around that center, starting from the first
> point and ending on the line that is perpendicular to the second field
> vector. Approximate the arc with a straight line. Evaluate the field
> at the end of the arc, which will be nearly parallel to the second
> field vector that you evaluated. Repeat.
> 
> At http://www.matterandinteractions.org/Content/Materials/programs2.html
> you'll find a program fields.py which you might find interesting, as
> it displays many properties of E and B fields, but not field lines
> (nor equipotential lines/surfaces).
> 
> Bruce Sherwood
> 
> On Wed, Apr 20, 2011 at 6:47 AM,  <dal...@ea...> wrote:
>> I'm looking for a way to draw E and B fields using vPython. I have the equations to find the vector at a point, but want to draw contour lines between two particles just as a start. Any suggestions or code segment that shows how to do that?
>> 
>> Thanks,
>> -d
> 
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Re: [Visualpython-users] Contour lines using vPython

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

The curve object will connect a list of points with line segments,
which sounds like what you want.

There is a trick to drawing field lines which you might wish to
implement, to avoid a systematic error. From a starting point where
you know the field direction, project a line in that direction and
evaluate the field at a new location on that line. Draw perpendiculars
to the two vectors and find where those perpendiculars meet (this is
assuming a 2D field). Imagine that point as the center of a circle,
and swing a circular arc around that center, starting from the first
point and ending on the line that is perpendicular to the second field
vector. Approximate the arc with a straight line. Evaluate the field
at the end of the arc, which will be nearly parallel to the second
field vector that you evaluated. Repeat.

At http://www.matterandinteractions.org/Content/Materials/programs2.html
you'll find a program fields.py which you might find interesting, as
it displays many properties of E and B fields, but not field lines
(nor equipotential lines/surfaces).

Bruce Sherwood

On Wed, Apr 20, 2011 at 6:47 AM,  <dal...@ea...> wrote:
> I'm looking for a way to draw E and B fields using vPython. I have the equations to find the vector at a point, but want to draw contour lines between two particles just as a start. Any suggestions or code segment that shows how to do that?
>
> Thanks,
> -d

[Visualpython-users] Contour lines using vPython

[<dal...@ea...>]

I'm looking for a way to draw E and B fields using vPython. I have the equations to find the vector at a point, but want to draw contour lines between two particles just as a start. Any suggestions or code segment that shows how to do that?

Thanks,
-d

Re: [Visualpython-users] text object

[Aaron M. <mav...@gm...>]

On Fri, Apr 15, 2011 at 9:32 AM, Jason Morgan <j.a...@gm...> wrote:
> It seems the text object has been removed from the API?

The text object is still in the API. However, it may be failing on
something related to fonts. Do you have TTFQuery installed? If so, and
it still doesn't work, reply with the error you're seeing.

-- 
Aaron Mavrinac
www.mavrinac.com

[Visualpython-users] text object

[Jason M. <j.a...@gm...>]

Hi,

 I'm doing a demo of some Python and just found that the VPython stonehenge.py example no longer works.

 Using ubunu 10.10 and the python-visual aptitude package (visual v5.12)

 It seems the text object has been removed from the API?

 Surely if it's been depricated, surely a wrapper should still exist to emulate the prior function.

 e.g.

 text=extrustion(type=text)


 Cheers,
 Jason.