Thread: [Visualpython-users] What about integrating ODE PyODE and VPython ?

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What about integrating ODE PyODE and VPython ?

Is there any body thinking on that ?

I think that this could be a super project with a very very future in =
physics simulations...

Thanks....
It could indeed make a lot of sense to use VPython to visualize the=20
results of PyODE, but we do not intend to build any physics into VPython=20
itself, nor is there a need to do so in order to exploit PyODE or other=20
computational packages. The goal of VPython is to make it easy to do 3D=20
animations driven by calculations, not to do those calculations. That is=20
why VPython handles 3D geometry (3D vector computations and 3D=20
rendering), but it doesn't "know" any physics or chemistry or electrical=20
engineering or.... And won't in the future, either.

Bruce Sherwood

Jos=E9 A Mart=EDn H wrote:

> What about integrating ODE PyODE and VPython ?
>=20
> Is there any body thinking on that ?
> =20
> I think that this could be a super project with a very very future in=20
> physics simulations...
> =20
> Thanks....

I have been working on integrating pyODE with VPython, actually.  But, I
have been having a problem with VPython's near-clipping plane moving
forward into the scene when an object moves away from the visible
scene.  No word yet on any fix, but a bug report has been filed.  This
has actually been quite easy so far.

On Wed, 2004-08-11 at 13:49, Jos=E9 A Mart=EDn H wrote:
> =20
>=20
> What about integrating ODE PyODE and VPython ?
>=20
>=20
> Is there any body thinking on that ?
> =20
> I think that this could be a super project with a very very future in
> physics simulations...
> =20
> Thanks....
--=20

Isaac W Hanson
Lead Software Developer;
Omnidox, LC; http://www.omnidox.com

Dear Isaac W Hanson
Are you doing so as a project ?, or a personal project maybe ?
could you show me some of your project ? or  can i obtain it from a website
?

Thanks...

----- Original Message ----- 
From: "Isaac W Hanson" <isa...@om...>
To: <vis...@li...>
Sent: Wednesday, August 11, 2004 8:34 PM
Subject: Re: [Visualpython-users] What about integrating ODE PyODE
andVPython ?

> I have been working on integrating pyODE with VPython, actually.  But, I
> have been having a problem with VPython's near-clipping plane moving
> forward into the scene when an object moves away from the visible
> scene.  No word yet on any fix, but a bug report has been filed.  This
> has actually been quite easy so far.
>
> On Wed, 2004-08-11 at 13:49, José A Martín H wrote:
> >
> >
> > What about integrating ODE PyODE and VPython ?
> >
> >
> > Is there any body thinking on that ?
> >
> > I think that this could be a super project with a very very future in
> > physics simulations...
> >
> > Thanks....
> -- 
>
> Isaac W Hanson
> Lead Software Developer;
> Omnidox, LC; http://www.omnidox.com
>
>
>
> -------------------------------------------------------
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> _______________________________________________
> Visualpython-users mailing list
> Vis...@li...
> https://lists.sourceforge.net/lists/listinfo/visualpython-users
>

I am in the *very* early stages of a personal project.  The plan is to
simulate organisms evolving in a virtual environment.  Very similar to
Karl Sims' "Blockies" project, except rather than evolving individual
creatures for an explicit purpose, the idea is to start with a very
simple self-replicating "organism" and allow some sort of
society/ecosystem to develop "naturally". =20

I am in the early stages of deciding what physical properties I would
like to implement, but the problem with the near-clipping plane has me
looking for an alternative to VPython, and has sent me scrambling to
learn enough about GL to fix the bug myself (not going to well).

I would be happy to give you what little code I have developed, to do
with as you please, though I imagine we should continue this discussion
outside the VPython mailing list.  When I get back to my abode tonight,
I will package that for you.

 - Isaac

On Wed, 2004-08-11 at 14:47, Jos=E9 A Mart=EDn H wrote:
> Dear Isaac W Hanson
> Are you doing so as a project ?, or a personal project maybe ?
> could you show me some of your project ? or  can i obtain it from a websi=
te
> ?
>=20
> Thanks...
>=20
> ----- Original Message -----=20
> From: "Isaac W Hanson" <isa...@om...>
> To: <vis...@li...>
> Sent: Wednesday, August 11, 2004 8:34 PM
> Subject: Re: [Visualpython-users] What about integrating ODE PyODE
> andVPython ?
>=20
>=20
> > I have been working on integrating pyODE with VPython, actually.  But, =
I
> > have been having a problem with VPython's near-clipping plane moving
> > forward into the scene when an object moves away from the visible
> > scene.  No word yet on any fix, but a bug report has been filed.  This
> > has actually been quite easy so far.
> >
> > On Wed, 2004-08-11 at 13:49, Jos=E9 A Mart=EDn H wrote:
> > >
> > >
> > > What about integrating ODE PyODE and VPython ?
> > >
> > >
> > > Is there any body thinking on that ?
> > >
> > > I think that this could be a super project with a very very future in
> > > physics simulations...
> > >
> > > Thanks....
> > --=20
> >
> > Isaac W Hanson
> > Lead Software Developer;
> > Omnidox, LC; http://www.omnidox.com
> >
> >
> >
> > -------------------------------------------------------
> > SF.Net email is sponsored by Shop4tech.com-Lowest price on Blank Media
> > 100pk Sonic DVD-R 4x for only $29 -100pk Sonic DVD+R for only $33
> > Save 50% off Retail on Ink & Toner - Free Shipping and Free Gift.
> > http://www.shop4tech.com/z/Inkjet_Cartridges/9_108_r285
> > _______________________________________________
> > Visualpython-users mailing list
> > Vis...@li...
> > https://lists.sourceforge.net/lists/listinfo/visualpython-users
> >
--=20

Isaac W Hanson
Lead Software Developer;
Omnidox, LC; http://www.omnidox.com

I don't understand the "near-clipping plane" problem. Is it simply that 
you want to set scene.autoscale = 0?

Here is the bug report you submitted, for Linux:

"My program is a test of a rigid body simulation package, pyode. The
scene consists of a few boxes near position (0,0,0) and a sphere.
The sphere starts from a position behind the viewer, rolls towards
the boxes, crashes into them, bounces back towards the viewer,
then continues to roll far behind the viewer. After the sphere rolls
for a little while, the near clipping plane begins to move forward into
the scene. I have "autocenter" turned off, and the forward
progression of the near clipping plane seems to be related to the
distance of the sphere from the scene."

I wrote a similar-sounding program, which seems to behave properly:

box(color=color.cyan)
s = sphere(pos=(0,0,100), color=color.red)
dz = -1
##scene.autocenter = 0
##scene.autoscale = 0
while 1:
     rate(20)
     s.pos += vector(0,0,dz)
     if s.pos.z < 1:
         dz = -dz

Turning off autocenter doesn't do anything that I can see. With the 
default autoscale on, the camera is moved to make sure that you always 
see something. I'm not sure what you want to have happen, but it sounds 
to me like you should turn off autoscaling and manage the view yourself.

Bruce Sherwood

Isaac W Hanson wrote:

> I am in the *very* early stages of a personal project.  The plan is to
> simulate organisms evolving in a virtual environment.  Very similar to
> Karl Sims' "Blockies" project, except rather than evolving individual
> creatures for an explicit purpose, the idea is to start with a very
> simple self-replicating "organism" and allow some sort of
> society/ecosystem to develop "naturally".  
> 
> I am in the early stages of deciding what physical properties I would
> like to implement, but the problem with the near-clipping plane has me
> looking for an alternative to VPython, and has sent me scrambling to
> learn enough about GL to fix the bug myself (not going to well).
> 
> I would be happy to give you what little code I have developed, to do
> with as you please, though I imagine we should continue this discussion
> outside the VPython mailing list.  When I get back to my abode tonight,
> I will package that for you.
> 
>  - Isaac

On Wed, 2004-08-11 at 16:51, Bruce Sherwood wrote:
> I don't understand the "near-clipping plane" problem. Is it simply that 
> you want to set scene.autoscale = 0?
> 
> Here is the bug report you submitted, for Linux:
> 
> "My program is a test of a rigid body simulation package, pyode. The
> scene consists of a few boxes near position (0,0,0) and a sphere.
> The sphere starts from a position behind the viewer, rolls towards
> the boxes, crashes into them, bounces back towards the viewer,
> then continues to roll far behind the viewer. After the sphere rolls
> for a little while, the near clipping plane begins to move forward into
> the scene. I have "autocenter" turned off, and the forward
> progression of the near clipping plane seems to be related to the
> distance of the sphere from the scene."
> 
> I wrote a similar-sounding program, which seems to behave properly:
> 
> box(color=color.cyan)
> s = sphere(pos=(0,0,100), color=color.red)
> dz = -1
> ##scene.autocenter = 0
> ##scene.autoscale = 0
> while 1:
>      rate(20)
>      s.pos += vector(0,0,dz)
>      if s.pos.z < 1:
>          dz = -dz
> 
> Turning off autocenter doesn't do anything that I can see. With the 
> default autoscale on, the camera is moved to make sure that you always 
> see something. I'm not sure what you want to have happen, but it sounds 
> to me like you should turn off autoscaling and manage the view yourself.
> 
> Bruce Sherwood

No, it is a legitimate complaint.  For example, run stars with a lot of
stars and velocity such that at least a few stars fly away and there is
plenty to look at in the middle for a while.  Zoom the camera into the
scene, and position the camera such that a trail is "in your face".  You
should be able to see the cross-section of the trail as it is clipped by
the near clipping plane.  As some of the stars fly away from the
cluster, you will notice the plane slowly move further into the scene. 
Eventually, it will cut deeply into the scene.

I just committed a fix for this problem into CVS a few minutes ago. 
Basically, the new behavior is that system decides if the camera might
be located within the scene's bounding box, and if so, sets the near
clipping plane distance to a small fixed value.

Previously, the distance was set to a fixed multiple of the scaled
extent of the scene.  A scene whose objects span a volume much larger
than the display's viewing volume would have an inappropriately large
near clipping plane distance.

-Jonathan

I'm glad Jonathan understood, as I obviously didn't. Also, Isaac Hanson 
sent me the following test routine which shows the problem:

import visual

visual.box(height=10, width=10, length=10, color=visual.color.cyan)
s = visual.sphere(pos=(0,0,-1180), color=visual.color.red)

visual.scene.autocenter = 0
visual.scene.autoscale = 0

while 1:
     visual.rate(30)
     s.pos.z += -1

Zoom in (manually) so the cube fills much of the window, and wait. 
You'll see the creep.

Bruce Sherwood

Jonathan Brandmeyer wrote:

> On Wed, 2004-08-11 at 16:51, Bruce Sherwood wrote:
> 
>>I don't understand the "near-clipping plane" problem. Is it simply that 
>>you want to set scene.autoscale = 0?
>>
>>Here is the bug report you submitted, for Linux:
>>
>>"My program is a test of a rigid body simulation package, pyode. The
>>scene consists of a few boxes near position (0,0,0) and a sphere.
>>The sphere starts from a position behind the viewer, rolls towards
>>the boxes, crashes into them, bounces back towards the viewer,
>>then continues to roll far behind the viewer. After the sphere rolls
>>for a little while, the near clipping plane begins to move forward into
>>the scene. I have "autocenter" turned off, and the forward
>>progression of the near clipping plane seems to be related to the
>>distance of the sphere from the scene."
>>
>>I wrote a similar-sounding program, which seems to behave properly:
>>
>>box(color=color.cyan)
>>s = sphere(pos=(0,0,100), color=color.red)
>>dz = -1
>>##scene.autocenter = 0
>>##scene.autoscale = 0
>>while 1:
>>     rate(20)
>>     s.pos += vector(0,0,dz)
>>     if s.pos.z < 1:
>>         dz = -dz
>>
>>Turning off autocenter doesn't do anything that I can see. With the 
>>default autoscale on, the camera is moved to make sure that you always 
>>see something. I'm not sure what you want to have happen, but it sounds 
>>to me like you should turn off autoscaling and manage the view yourself.
>>
>>Bruce Sherwood
> 
> 
> No, it is a legitimate complaint.  For example, run stars with a lot of
> stars and velocity such that at least a few stars fly away and there is
> plenty to look at in the middle for a while.  Zoom the camera into the
> scene, and position the camera such that a trail is "in your face".  You
> should be able to see the cross-section of the trail as it is clipped by
> the near clipping plane.  As some of the stars fly away from the
> cluster, you will notice the plane slowly move further into the scene. 
> Eventually, it will cut deeply into the scene.
> 
> I just committed a fix for this problem into CVS a few minutes ago. 
> Basically, the new behavior is that system decides if the camera might
> be located within the scene's bounding box, and if so, sets the near
> clipping plane distance to a small fixed value.
> 
> Previously, the distance was set to a fixed multiple of the scaled
> extent of the scene.  A scene whose objects span a volume much larger
> than the display's viewing volume would have an inappropriately large
> near clipping plane distance.
> 
> -Jonathan
> 
> 
> 
> -------------------------------------------------------
> SF.Net email is sponsored by Shop4tech.com-Lowest price on Blank Media
> 100pk Sonic DVD-R 4x for only $29 -100pk Sonic DVD+R for only $33
> Save 50% off Retail on Ink & Toner - Free Shipping and Free Gift.
> http://www.shop4tech.com/z/Inkjet_Cartridges/9_108_r285
> _______________________________________________
> Visualpython-users mailing list
> Vis...@li...
> https://lists.sourceforge.net/lists/listinfo/visualpython-users

Thread: [Visualpython-users] What about integrating ODE PyODE and VPython ?

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