visualpython-users

[Visualpython-users] Re: Vpython segmentation fault

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

This sounds somewhat familiar. Can someone who has had experience with this
issue on Linux comment? Thanks!

I tried to post this with the attachments that Craig furnished, but it
bounced back (message too big). If you need to see those documents, you
could email him directly for copies.

Bruce Sherwood

----- Original Message -----
From: "Craig Gallek" <cg...@an...>
To: <bas...@un...>
Sent: Friday, January 31, 2003 2:28 PM
Subject: Vpython segmentation fault


>
> Hello,
>
>  I am in the Chemistry and Computer Science departments at Carnegie
> Mellon University.  We use VPython in our research lab.  I am having
> some problems with the package and I was wondering who the current
> developers of the project are.  Your name was the only e-mail address
> listed on the VPython web site.  If I am contacting the wrong person,
> please redirect me to the proper place.
>
> Up until about a week ago, VPython was working properly on our cluster.
> We just updated our Linux machines last week.  The upgrade included the
> new versions of gtk2 and gcc 3.2.  However, the old versions of gtk 1.2
> and gcc 2.95 are still on the machines as well.  Certain function in
> VPython now cause python to Segfault without displaying any
> information.  I tried recompiling the VPython library against the new
> versions of the software that we had installed and against the old
> versions, but the same thing happens.  I have attached a gdb backtrace
> and strace of a crash that occurs when the dot product function is
> called on two unit vectors.  I don't understand all of the 'file not
> found' errors in the strace.  These files are present and have the
> proper permissions set.  None of the python files were touched during
> the upgrade, so I'm a bit stumped.  Do you know of any complications
> with VPython and the new versions of gtk and gcc?
>
> Any help would be greatly appreciated.
>
> Thank you,
> Craig Gallek
>

[Visualpython-users] Help for desiging a space i n Vpython.

[Tom M. <mun...@st...>]

I am new to Python and Vpython, but have really been impressed with what
I can do so simply.  Instead of writing a "hello world" program, I
tweaked the random boxes demo program and created a grid to indicate a
space.  One thing lead to another, and I am working up a whole scheme
called ProtoSpace.  http://www.givingspace.org/protospace and the
program is at  http://www.givingspace.org/protospace/space01.py 

I want to add agents, called Angels, which will fly around the space.
Does anyone know of an Angel figure, a cute little cherub figure with
flapping wings, that I could show flying around the space?  I'd like to
also "lock on" to the angel, mounting the camera on the angels' back,
showing an angel's-eye view of the space.  The wings would be visible,
but transparent, so as to not block the view.

I don't really need a high res image, I suppose I could use a sphere
instead, but I am demonstrating this idea next week and would like to
spruce it up a little.  

Any help or pointers to anything related to this would be greatly
appreciated.

Thanks...

Tom Munnecke
Visiting Scholar
Digital Visions Program
Stanford University

Re: [Visualpython-users] Help for desiging a space i n Vpython.

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

Alas, I have to reveal an unfortunate fact of life: There are no angels.

Seriously, a major gap in VPython is that there is no way to import a 3D
model from some other modeling package or format. The only thing you can do
at present is use the low-level primitive object "faces" and create the
object yourself out of shaded triangles. Or as you say approximate an angel
by a sphere!

Moreover, there is no transparency, a difficult effect to achieve in a
real-time 3D renderer.

As for flying through space carrying the camera, see the demo program
stonehenge.py, where the basic idea is to keep moving scene.center to give
the effect you want.

Bruce Sherwood

----- Original Message -----
From: "Tom Munnecke" <mun...@st...>
To: "'vpusers'" <vis...@li...>
Sent: Friday, January 31, 2003 5:22 PM
Subject: [Visualpython-users] Help for desiging a space i n Vpython.


> I am new to Python and Vpython, but have really been impressed with what
> I can do so simply.  Instead of writing a "hello world" program, I
> tweaked the random boxes demo program and created a grid to indicate a
> space.  One thing lead to another, and I am working up a whole scheme
> called ProtoSpace.  http://www.givingspace.org/protospace and the
> program is at  http://www.givingspace.org/protospace/space01.py
>
> I want to add agents, called Angels, which will fly around the space.
> Does anyone know of an Angel figure, a cute little cherub figure with
> flapping wings, that I could show flying around the space?  I'd like to
> also "lock on" to the angel, mounting the camera on the angels' back,
> showing an angel's-eye view of the space.  The wings would be visible,
> but transparent, so as to not block the view.
>
> I don't really need a high res image, I suppose I could use a sphere
> instead, but I am demonstrating this idea next week and would like to
> spruce it up a little.
>
> Any help or pointers to anything related to this would be greatly
> appreciated.
>
> Thanks...
>
> Tom Munnecke
> Visiting Scholar
> Digital Visions Program
> Stanford University
>
>
>
>
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