visualpython-users

Re: [Visualpython-users] Error with forward and up

[alessandro <bom...@gm...>]

OK. So the only way is to use Visual 5? I need some help installing 
Visual 5 on Ubuntu Hardy. I've tried to install the package made by Guy 
K. Kloss here

https://gutefee.massey.ac.nz/moin/Python/3D

but when I use in my prog. it doesn't work. I'm using pygtk and glade building my app. 

I have this func main:


def main():
    global scena1     # my scene
    global griglia
    global nomefile
  
    app.signal_autoconnect(dic)

    gui_main.show()
    gui_main.move(0,0)
    scena1 = disegno.nuovo()         # call to my  drawing -module
   
    disegno.xyz(100)                        # here I draw 3 arrow (my 
xyz axis)
    griglia = 2000                             
    step=100
    disegno.base(-griglia,-griglia,griglia,griglia,step,True)   # here I 
draw a grid (my ground plane)
   
  
    gtk.main()



Running the app must appear 3 wins: my main win, a second win (the 
option) and the Visual win (with the grid and the 3 arrow). But 
everything seems to be "freezed". with Visual 3 it work fine. I think 
there is something wrong with the gtk.main

Alessandro Barracco




Bruce Sherwood ha scritto:
> If you're willing to use the newer Visual 5, this problem has been 
> fixed. There is no way in Visual 3 around this other than never to 
> point the camera exactly in the direction of up or -up.
>
> (The fix in Visual 5 is quite technical: It consists of adjusting 
> scene.forward whenever it is exactly in the direction of scene.up or 
> -scene.up to point in a slightly different direction as far as the 
> view is concerned, and the human viewer doesn't notice.)
>
> Bruce Sherwood

Re: [Visualpython-users] rotation of camera

[Rob S. <rsa...@mt...>]

I find it convenient to define  DEG=math.pi/180.
so that I can write, for example, 30*DEG.

Rob Salgado




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Re: [Visualpython-users] rotation of camera

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

Footnote: the "radians" and "degrees" functions actually come from the math 
module, as do functions such as sin, cos, and sqrt. Visual automatically imports 
the math module and the array module "numpy" (or the older Numeric for Visual 
3). But it makes sense to advertise the radians and degrees functions in the 
Visual documentation dealing with rotations.

Of course radians(x) is equivalent o x*pi/180, and degrees(x) is equivalent to 
x*180/pi.

Bruce Sherwood

Bruce Sherwood wrote:
> Oh, now I see your point. I did misread the original question. (I didn't even 
> realize that there is a Visual function "radians"! I better get this into the 
> documentation.)
> 
> But there's nothing wrong with the radians function: it's doing its job of 
> converting radians(90) into pi/2 radians. The problem is that in the first 
> iteration through the loop the rotation is through 0, the next time through 1 
> degree, the next time through 2 degrees STARTING FROM A DIRECTION THAT HAD 
> ALREADY BEEN ROTATED 1 degree, so the new direction is 3 degrees away from the 
> original direction. The next rotation will be by 3 degrees, for a total rotation 
> of 6 degrees, etc.
> 
> So my corrections to those programs should have said
> 
> 	....rotate(angle=radians(1), .....
> 
> That way one is always rotating by 1 degree each time through the loop.
> 
> Bruce Sherwood
> 
> Lenore Horner wrote:
>> The command "radians" which he was using to turn his degree angles into 
>> radian angles.
>>
>> On Apr 18, 2009, at 12:48 , Bruce Sherwood wrote:
>>
>>> What is there to squawk about? 90 radians is a completely legal angle.
>>>
>>> Bruce Sherwood
>>>
>>> Lenore Horner wrote:
>>>> VPython doesn't have a radians command to turn degrees into radians?  
>>>> Shouldn't it squawk when he uses an illegal command?
>>>> Lenore
>>>> On Apr 18, 2009, at 11:40 , Bruce Sherwood wrote:
>>>>> The angle used by rotations must be in radians, not degrees.
>>>>>
>>>>> You want ....rotate(angle=alfa*pi/180, ....
>>>>>
>>>>> Bruce Sherwood
>>>>>
>>>>> alessandro wrote:
>>>>>> I want to rotate 90° around the center objects  with an animation. I
>>>>>> tried this:
>>>>>>
>>>>>>
>>>>>> from visual import *
>>>>>> ball = sphere(pos=(-5,0,0), radius=0.5, color=color.red)
>>>>>> wallR = box(pos=(6,0,0), size=(0.2,4,4), color=color.green)
>>>>>> alfa=0
>>>>>> while alfa < radians(90):
>>>>>>   rate(20)
>>>>>>
>>>>>>   scene.forward = scene.forward.rotate(angle=alfa, axis=(0,1,0))
>>>>>>
>>>>>>   alfa += radians(1)
>>>>>>
>>>>>> both the sphere & box rotate but they rotate for not only for 90° but
>>>>>> serveral time. Where is the error?
>>>>>>
>>>>>> ------------------------------------------------------------------------------ 
>>>>>>
>>>>>> Stay on top of everything new and different, both inside and
>>>>>> around Java (TM) technology - register by April 22, and save
>>>>>> $200 on the JavaOne (SM) conference, June 2-5, 2009, San Francisco.
>>>>>> 300 plus technical and hands-on sessions. Register today.
>>>>>> Use priority code J9JMT32. http://p.sf.net/sfu/p
>>>>>> _______________________________________________
>>>>>> Visualpython-users mailing list
>>>>>> Vis...@li...
>>>>>> https://lists.sourceforge.net/lists/listinfo/visualpython-users
>>>>> ------------------------------------------------------------------------------ 
>>>>>
>>>>> Stay on top of everything new and different, both inside and
>>>>> around Java (TM) technology - register by April 22, and save
>>>>> $200 on the JavaOne (SM) conference, June 2-5, 2009, San Francisco.
>>>>> 300 plus technical and hands-on sessions. Register today.
>>>>> Use priority code J9JMT32. http://p.sf.net/sfu/p
>>>>> _______________________________________________
>>>>> Visualpython-users mailing list
>>>>> Vis...@li...
>>>>> https://lists.sourceforge.net/lists/listinfo/visualpython-users
>>>>>
> 
> ------------------------------------------------------------------------------
> Stay on top of everything new and different, both inside and 
> around Java (TM) technology - register by April 22, and save
> $200 on the JavaOne (SM) conference, June 2-5, 2009, San Francisco.
> 300 plus technical and hands-on sessions. Register today. 
> Use priority code J9JMT32. http://p.sf.net/sfu/p
> _______________________________________________
> Visualpython-users mailing list
> Vis...@li...
> https://lists.sourceforge.net/lists/listinfo/visualpython-users

Re: [Visualpython-users] rotation of camera

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

Oh, now I see your point. I did misread the original question. (I didn't even 
realize that there is a Visual function "radians"! I better get this into the 
documentation.)

But there's nothing wrong with the radians function: it's doing its job of 
converting radians(90) into pi/2 radians. The problem is that in the first 
iteration through the loop the rotation is through 0, the next time through 1 
degree, the next time through 2 degrees STARTING FROM A DIRECTION THAT HAD 
ALREADY BEEN ROTATED 1 degree, so the new direction is 3 degrees away from the 
original direction. The next rotation will be by 3 degrees, for a total rotation 
of 6 degrees, etc.

So my corrections to those programs should have said

	....rotate(angle=radians(1), .....

That way one is always rotating by 1 degree each time through the loop.

Bruce Sherwood

Lenore Horner wrote:
> The command "radians" which he was using to turn his degree angles into 
> radian angles.
> 
> On Apr 18, 2009, at 12:48 , Bruce Sherwood wrote:
> 
>> What is there to squawk about? 90 radians is a completely legal angle.
>>
>> Bruce Sherwood
>>
>> Lenore Horner wrote:
>>> VPython doesn't have a radians command to turn degrees into radians?  
>>> Shouldn't it squawk when he uses an illegal command?
>>> Lenore
>>> On Apr 18, 2009, at 11:40 , Bruce Sherwood wrote:
>>>> The angle used by rotations must be in radians, not degrees.
>>>>
>>>> You want ....rotate(angle=alfa*pi/180, ....
>>>>
>>>> Bruce Sherwood
>>>>
>>>> alessandro wrote:
>>>>> I want to rotate 90° around the center objects  with an animation. I
>>>>> tried this:
>>>>>
>>>>>
>>>>> from visual import *
>>>>> ball = sphere(pos=(-5,0,0), radius=0.5, color=color.red)
>>>>> wallR = box(pos=(6,0,0), size=(0.2,4,4), color=color.green)
>>>>> alfa=0
>>>>> while alfa < radians(90):
>>>>>   rate(20)
>>>>>
>>>>>   scene.forward = scene.forward.rotate(angle=alfa, axis=(0,1,0))
>>>>>
>>>>>   alfa += radians(1)
>>>>>
>>>>> both the sphere & box rotate but they rotate for not only for 90° but
>>>>> serveral time. Where is the error?
>>>>>
>>>>> ------------------------------------------------------------------------------ 
>>>>>
>>>>> Stay on top of everything new and different, both inside and
>>>>> around Java (TM) technology - register by April 22, and save
>>>>> $200 on the JavaOne (SM) conference, June 2-5, 2009, San Francisco.
>>>>> 300 plus technical and hands-on sessions. Register today.
>>>>> Use priority code J9JMT32. http://p.sf.net/sfu/p
>>>>> _______________________________________________
>>>>> Visualpython-users mailing list
>>>>> Vis...@li...
>>>>> https://lists.sourceforge.net/lists/listinfo/visualpython-users
>>>>
>>>> ------------------------------------------------------------------------------ 
>>>>
>>>> Stay on top of everything new and different, both inside and
>>>> around Java (TM) technology - register by April 22, and save
>>>> $200 on the JavaOne (SM) conference, June 2-5, 2009, San Francisco.
>>>> 300 plus technical and hands-on sessions. Register today.
>>>> Use priority code J9JMT32. http://p.sf.net/sfu/p
>>>> _______________________________________________
>>>> Visualpython-users mailing list
>>>> Vis...@li...
>>>> https://lists.sourceforge.net/lists/listinfo/visualpython-users
>>>>
> 

Re: [Visualpython-users] Error with forward and up

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

If you're willing to use the newer Visual 5, this problem has been fixed. There 
is no way in Visual 3 around this other than never to point the camera exactly 
in the direction of up or -up.

(The fix in Visual 5 is quite technical: It consists of adjusting scene.forward 
whenever it is exactly in the direction of scene.up or -scene.up to point in a 
slightly different direction as far as the view is concerned, and the human 
viewer doesn't notice.)

Bruce Sherwood

alessandro wrote:
> I create 3 icons in my prog.:
> 
> Top.view
> Front-view
> Side-view
> 
> I change the forward attribute of my scene (named scena1). I set 
> scena1.up = vector (0,0,1) and define 3 func:
> 
> def vista_alto(obj):
>     global scena1
>     scena1.forward = vector(0,0,-1)
>    
> def vista_fronte(obj):
>     global scena1
>     scena1.forward = vector(0,-1,0)
> 
> def vista_lato(obj):
>     global scena1
>     scena1.forward = vector(-1,0,0)
> 
> but when click on the top-view (1° def) an error appears:
> 
> *scena1.forward = vector(-1,0,0)
> ValueError: forward may not be colinear with up.*
> 
> Reading the documentation I found this requirement but I'm not able to 
> solve it. How can I do?
> 
> Alessandro Barracco
> 
> 
> ------------------------------------------------------------------------
> 
> ------------------------------------------------------------------------------
> Stay on top of everything new and different, both inside and 
> around Java (TM) technology - register by April 22, and save
> $200 on the JavaOne (SM) conference, June 2-5, 2009, San Francisco.
> 300 plus technical and hands-on sessions. Register today. 
> Use priority code J9JMT32. http://p.sf.net/sfu/p
> 
> 
> ------------------------------------------------------------------------
> 
> _______________________________________________
> Visualpython-users mailing list
> Vis...@li...
> https://lists.sourceforge.net/lists/listinfo/visualpython-users

Re: [Visualpython-users] rotation of camera

[Lenore H. <lh...@si...>]

The command "radians" which he was using to turn his degree angles  
into radian angles.

On Apr 18, 2009, at 12:48 , Bruce Sherwood wrote:

> What is there to squawk about? 90 radians is a completely legal angle.
>
> Bruce Sherwood
>
> Lenore Horner wrote:
>> VPython doesn't have a radians command to turn degrees into  
>> radians?  Shouldn't it squawk when he uses an illegal command?
>> Lenore
>> On Apr 18, 2009, at 11:40 , Bruce Sherwood wrote:
>>> The angle used by rotations must be in radians, not degrees.
>>>
>>> You want ....rotate(angle=alfa*pi/180, ....
>>>
>>> Bruce Sherwood
>>>
>>> alessandro wrote:
>>>> I want to rotate 90° around the center objects  with an  
>>>> animation. I
>>>> tried this:
>>>>
>>>>
>>>> from visual import *
>>>> ball = sphere(pos=(-5,0,0), radius=0.5, color=color.red)
>>>> wallR = box(pos=(6,0,0), size=(0.2,4,4), color=color.green)
>>>> alfa=0
>>>> while alfa < radians(90):
>>>>   rate(20)
>>>>
>>>>   scene.forward = scene.forward.rotate(angle=alfa, axis=(0,1,0))
>>>>
>>>>   alfa += radians(1)
>>>>
>>>> both the sphere & box rotate but they rotate for not only for 90°  
>>>> but
>>>> serveral time. Where is the error?
>>>>
>>>> ------------------------------------------------------------------------------
>>>> Stay on top of everything new and different, both inside and
>>>> around Java (TM) technology - register by April 22, and save
>>>> $200 on the JavaOne (SM) conference, June 2-5, 2009, San Francisco.
>>>> 300 plus technical and hands-on sessions. Register today.
>>>> Use priority code J9JMT32. http://p.sf.net/sfu/p
>>>> _______________________________________________
>>>> Visualpython-users mailing list
>>>> Vis...@li...
>>>> https://lists.sourceforge.net/lists/listinfo/visualpython-users
>>>
>>> ------------------------------------------------------------------------------
>>> Stay on top of everything new and different, both inside and
>>> around Java (TM) technology - register by April 22, and save
>>> $200 on the JavaOne (SM) conference, June 2-5, 2009, San Francisco.
>>> 300 plus technical and hands-on sessions. Register today.
>>> Use priority code J9JMT32. http://p.sf.net/sfu/p
>>> _______________________________________________
>>> Visualpython-users mailing list
>>> Vis...@li...
>>> https://lists.sourceforge.net/lists/listinfo/visualpython-users
>>>

[Visualpython-users] Error with forward and up

[alessandro <bom...@gm...>]

I create 3 icons in my prog.:

Top.view
Front-view
Side-view

I change the forward attribute of my scene (named scena1). I set 
scena1.up = vector (0,0,1) and define 3 func:

def vista_alto(obj):
    global scena1
    scena1.forward = vector(0,0,-1)
   
def vista_fronte(obj):
    global scena1
    scena1.forward = vector(0,-1,0)

def vista_lato(obj):
    global scena1
    scena1.forward = vector(-1,0,0)

but when click on the top-view (1° def) an error appears:

*scena1.forward = vector(-1,0,0)
ValueError: forward may not be colinear with up.*

Reading the documentation I found this requirement but I'm not able to 
solve it. How can I do?

Alessandro Barracco

Re: [Visualpython-users] rotation of camera

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

Your code fragment must be miscopied, because if alfa is in radians you 
shouldn't convert radians again in "angle = -alf*pi/180", you should just say 
"angle = -alf". I'm assuming that you actually had the latter form in your program.

Floating point numbers in computers are expressed in an approximate manner, so 
when you add up 90 terms, each of which is pi/180, the result may actually be 
less than 90*pi/180, even though the discrepancy is extremely small.

A secure way to handle such things is to use integers in the counting:

N = 0
while N <= 90:
    rate(30)
    scene.forward = scene.forward.rotate(angle=-N*pi/180, axis=(0,1,0))
    N+= 1

Bruce Sherwood

alessandro wrote:
> OK. now it works. But I must write like this:
> 
> 
> while alfa < 102*pi/180:
>    rate(30)
>    scene.forward = scene.forward.rotate(angle=-alfa*pi/180, axis=(0,1,0))
>    alfa += pi/180
> 
> 
> 
> why 102 instead of 90? With 90 the rotation in not pi/2 but lesser.
> 
> 
> 
> Bruce Sherwood ha scritto:
>> The angle used by rotations must be in radians, not degrees.
>>
>> You want ....rotate(angle=alfa*pi/180, ....
>>

Re: [Visualpython-users] rotation of camera

[alessandro <bom...@gm...>]

OK. now it works. But I must write like this:


while alfa < 102*pi/180:
    rate(30)
    scene.forward = scene.forward.rotate(angle=-alfa*pi/180, axis=(0,1,0))
    alfa += pi/180



why 102 instead of 90? With 90 the rotation in not pi/2 but lesser.



Bruce Sherwood ha scritto:
> The angle used by rotations must be in radians, not degrees.
>
> You want ....rotate(angle=alfa*pi/180, ....
>

Re: [Visualpython-users] rotation of camera

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

What is there to squawk about? 90 radians is a completely legal angle.

Bruce Sherwood

Lenore Horner wrote:
> VPython doesn't have a radians command to turn degrees into radians?  
> Shouldn't it squawk when he uses an illegal command?
> 
> Lenore
> 
> On Apr 18, 2009, at 11:40 , Bruce Sherwood wrote:
> 
>> The angle used by rotations must be in radians, not degrees.
>>
>> You want ....rotate(angle=alfa*pi/180, ....
>>
>> Bruce Sherwood
>>
>> alessandro wrote:
>>> I want to rotate 90° around the center objects  with an animation. I
>>> tried this:
>>>
>>>
>>> from visual import *
>>> ball = sphere(pos=(-5,0,0), radius=0.5, color=color.red)
>>> wallR = box(pos=(6,0,0), size=(0.2,4,4), color=color.green)
>>> alfa=0
>>> while alfa < radians(90):
>>>    rate(20)
>>>
>>>    scene.forward = scene.forward.rotate(angle=alfa, axis=(0,1,0))
>>>
>>>    alfa += radians(1)
>>>
>>> both the sphere & box rotate but they rotate for not only for 90° but
>>> serveral time. Where is the error?
>>>
>>> ------------------------------------------------------------------------------ 
>>>
>>> Stay on top of everything new and different, both inside and
>>> around Java (TM) technology - register by April 22, and save
>>> $200 on the JavaOne (SM) conference, June 2-5, 2009, San Francisco.
>>> 300 plus technical and hands-on sessions. Register today.
>>> Use priority code J9JMT32. http://p.sf.net/sfu/p
>>> _______________________________________________
>>> Visualpython-users mailing list
>>> Vis...@li...
>>> https://lists.sourceforge.net/lists/listinfo/visualpython-users
>>
>> ------------------------------------------------------------------------------ 
>>
>> Stay on top of everything new and different, both inside and
>> around Java (TM) technology - register by April 22, and save
>> $200 on the JavaOne (SM) conference, June 2-5, 2009, San Francisco.
>> 300 plus technical and hands-on sessions. Register today.
>> Use priority code J9JMT32. http://p.sf.net/sfu/p
>> _______________________________________________
>> Visualpython-users mailing list
>> Vis...@li...
>> https://lists.sourceforge.net/lists/listinfo/visualpython-users
>>
> 

Re: [Visualpython-users] rotation of camera

[Lenore H. <lh...@si...>]

VPython doesn't have a radians command to turn degrees into radians?   
Shouldn't it squawk when he uses an illegal command?

Lenore

On Apr 18, 2009, at 11:40 , Bruce Sherwood wrote:

> The angle used by rotations must be in radians, not degrees.
>
> You want ....rotate(angle=alfa*pi/180, ....
>
> Bruce Sherwood
>
> alessandro wrote:
>> I want to rotate 90° around the center objects  with an animation. I
>> tried this:
>>
>>
>> from visual import *
>> ball = sphere(pos=(-5,0,0), radius=0.5, color=color.red)
>> wallR = box(pos=(6,0,0), size=(0.2,4,4), color=color.green)
>> alfa=0
>> while alfa < radians(90):
>>    rate(20)
>>
>>    scene.forward = scene.forward.rotate(angle=alfa, axis=(0,1,0))
>>
>>    alfa += radians(1)
>>
>> both the sphere & box rotate but they rotate for not only for 90° but
>> serveral time. Where is the error?
>>
>> ------------------------------------------------------------------------------
>> Stay on top of everything new and different, both inside and
>> around Java (TM) technology - register by April 22, and save
>> $200 on the JavaOne (SM) conference, June 2-5, 2009, San Francisco.
>> 300 plus technical and hands-on sessions. Register today.
>> Use priority code J9JMT32. http://p.sf.net/sfu/p
>> _______________________________________________
>> Visualpython-users mailing list
>> Vis...@li...
>> https://lists.sourceforge.net/lists/listinfo/visualpython-users
>
> ------------------------------------------------------------------------------
> Stay on top of everything new and different, both inside and
> around Java (TM) technology - register by April 22, and save
> $200 on the JavaOne (SM) conference, June 2-5, 2009, San Francisco.
> 300 plus technical and hands-on sessions. Register today.
> Use priority code J9JMT32. http://p.sf.net/sfu/p
> _______________________________________________
> Visualpython-users mailing list
> Vis...@li...
> https://lists.sourceforge.net/lists/listinfo/visualpython-users
>

Re: [Visualpython-users] rotation of camera

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

The angle used by rotations must be in radians, not degrees.

You want ....rotate(angle=alfa*pi/180, ....

Bruce Sherwood

alessandro wrote:
> I want to rotate 90° around the center objects  with an animation. I 
> tried this:
> 
> 
> from visual import *
> ball = sphere(pos=(-5,0,0), radius=0.5, color=color.red)
> wallR = box(pos=(6,0,0), size=(0.2,4,4), color=color.green)
> alfa=0
> while alfa < radians(90):
>     rate(20)
>   
>     scene.forward = scene.forward.rotate(angle=alfa, axis=(0,1,0))
>    
>     alfa += radians(1)
> 
> both the sphere & box rotate but they rotate for not only for 90° but 
> serveral time. Where is the error?
> 
> ------------------------------------------------------------------------------
> Stay on top of everything new and different, both inside and 
> around Java (TM) technology - register by April 22, and save
> $200 on the JavaOne (SM) conference, June 2-5, 2009, San Francisco.
> 300 plus technical and hands-on sessions. Register today. 
> Use priority code J9JMT32. http://p.sf.net/sfu/p
> _______________________________________________
> Visualpython-users mailing list
> Vis...@li...
> https://lists.sourceforge.net/lists/listinfo/visualpython-users

[Visualpython-users] rotation of camera

[alessandro <bom...@gm...>]

I want to rotate 90° around the center objects  with an animation. I 
tried this:


from visual import *
ball = sphere(pos=(-5,0,0), radius=0.5, color=color.red)
wallR = box(pos=(6,0,0), size=(0.2,4,4), color=color.green)
alfa=0
while alfa < radians(90):
    rate(20)
  
    scene.forward = scene.forward.rotate(angle=alfa, axis=(0,1,0))
   
    alfa += radians(1)

both the sphere & box rotate but they rotate for not only for 90° but 
serveral time. Where is the error?

Re: [Visualpython-users] orthographic vs perpective view

[alessandro <bom...@gm...>]

Thanks, it works!!

Bruce Sherwood ha scritto:
> Not directly, but if you make scene.fov (field of view) very tiny (not 
> zero), you get something close to that.
>
> Bruce Sherwood
>
> alessandro wrote:
>> Is there a way to change the view from perspective to orthographic mode?
>>
>> ------------------------------------------------------------------------------ 
>>
>> Stay on top of everything new and different, both inside and around 
>> Java (TM) technology - register by April 22, and save
>> $200 on the JavaOne (SM) conference, June 2-5, 2009, San Francisco.
>> 300 plus technical and hands-on sessions. Register today. Use 
>> priority code J9JMT32. http://p.sf.net/sfu/p
>> _______________________________________________
>> Visualpython-users mailing list
>> Vis...@li...
>> https://lists.sourceforge.net/lists/listinfo/visualpython-users
>

Re: [Visualpython-users] orthographic vs perpective view

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

Not directly, but if you make scene.fov (field of view) very tiny (not zero), 
you get something close to that.

Bruce Sherwood

alessandro wrote:
> Is there a way to change the view from perspective to orthographic mode?
> 
> ------------------------------------------------------------------------------
> Stay on top of everything new and different, both inside and 
> around Java (TM) technology - register by April 22, and save
> $200 on the JavaOne (SM) conference, June 2-5, 2009, San Francisco.
> 300 plus technical and hands-on sessions. Register today. 
> Use priority code J9JMT32. http://p.sf.net/sfu/p
> _______________________________________________
> Visualpython-users mailing list
> Vis...@li...
> https://lists.sourceforge.net/lists/listinfo/visualpython-users

[Visualpython-users] orthographic vs perpective view

[alessandro <bom...@gm...>]

Is there a way to change the view from perspective to orthographic mode?

Re: [Visualpython-users] funny effects using opacity

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

 From the documentation on opacity:

"You may see incorrect rendering any time there is a translucent object (opacity 
< 1.0) which is not convex (e.g. ring), or two translucent objects which overlap 
on the screen and also in their depth extents (distances from the camera to the 
nearest and farthest planes perpendicular to scene.forward which intersect the 
object). The objects need not actually overlap in 3D space to have problems. The 
incorrect rendering will usually have the effect of making the more distant 
object disappear (fail to show through the nearer object). Accurate rendering of 
ad hoc scenes with translucency is difficult and expensive, and we did not want 
to wait for a perfect solution before introducing this useful enhancement."

In other words, it's a step forward to have opacity in VPython, and it works 
fine in many common situations, but the real-time nature of VPython means that 
for now it's not hard to find situations in which it doesn't work properly.

Bruce Sherwood

Guy K. Kloss wrote:
> Hi,
> 
> I have just tried to visualise a series of 288 measurement points in 3D using 
> vpython. All works quite nicely. As I'm using now the standard deviations of 
> each point in X, Y and Z direction for the size of the boxes I'm using to 
> render each point I had difficulties to see all points properly as they 
> overlapped. The solution was to set the (thanks for that) new feature to set 
> an opacity on the objects to 0.2.
> 
> Now unfortunately when rotating the scene I see that certain faces of the 
> cubes/boxes seem to be flickering on and off for the individual measurement 
> points. That's in a way quite annoying, especially as I'm assuming that not 
> all faces of the boxes then are rendered. Another assumption is, that 
> rendering polyhedrons the hidden faces are not rendered. But using opacity 
> there then are no truly hidden faces, and the scene looks quite different 
> with/without them.
> 
> Any ideas on how that could be fixed? I assume it needs fixing in vpython 
> itself, though. Or is it a "feature" of the OpenGL implementation on my 
> machine (Nvidia chipset on a Linux box, Ubuntu Jaunty)?
> 
> Guy
> 

[Visualpython-users] funny effects using opacity

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

Hi,

I have just tried to visualise a series of 288 measurement points in 3D using 
vpython. All works quite nicely. As I'm using now the standard deviations of 
each point in X, Y and Z direction for the size of the boxes I'm using to 
render each point I had difficulties to see all points properly as they 
overlapped. The solution was to set the (thanks for that) new feature to set 
an opacity on the objects to 0.2.

Now unfortunately when rotating the scene I see that certain faces of the 
cubes/boxes seem to be flickering on and off for the individual measurement 
points. That's in a way quite annoying, especially as I'm assuming that not 
all faces of the boxes then are rendered. Another assumption is, that 
rendering polyhedrons the hidden faces are not rendered. But using opacity 
there then are no truly hidden faces, and the scene looks quite different 
with/without them.

Any ideas on how that could be fixed? I assume it needs fixing in vpython 
itself, though. Or is it a "feature" of the OpenGL implementation on my 
machine (Nvidia chipset on a Linux box, Ubuntu Jaunty)?

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] Movie capture

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

I've updated the FAQ information on making movies using screen capture utilities 
to include the very easy to use Taksi freeware program. See

	http://vpython.org/contents/FAQ.html

Bruce Sherwood

[Visualpython-users] Better VIDLE instructions

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

In response to suggestions, the instructions for installing VIDLE have 
been improved. See http://vpython.org/vidle.

If you have used VPython for many years, you may remember that it used 
to be that you could make a change in your file while looking at the 
graphics window for the previous run, then re-run your new file and the 
old graphics window would immediately disappear and the new one appear. 
A few years ago changes were made to the standard IDLE that broke this 
convenient behavior, so that a re-run gave you TWO graphics windows. 
VIDLE restores the original useful behavior. VIDLE also restores 
important missing menu items on the Mac.

Bruce Sherwood

[Visualpython-users] Visual 5 from cvs - segmentation fault on amd64 boxes [Was: [Re: Visual 5 from cvs - segmentation fault]]

[LUK S. <shu...@po...>]

Bruce Sherwood wrote:
> I don't know what the problem is. Since the build went okay, I assume
> that there's nothing unusual to be seen in config.log or src/build.log?
> Does someone reading this have experience running Visual 5 on Debian?

Yes, that would be very much appreciated.

I tried the cvs build because the debian supplied package (which uses
boost 1.35) didn't work. Same seg fault. I filed a bug

http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=520472

but hasn't yet got a reply.

> 
> Since the fault is in the thread area, I draw your attention to this
> comment in INSTALL.txt in CVS about matching Boost and threadpool,
> though I think a mismatch would have stopped the build:

Yes, with threadpool 0.2.3 and 0.2.5, the build couldn't complete (with
boost 1.34).

I guess it's a 64-bit related problem as both the debian supplied and
locally built versions worked on my i386 laptop. I've changed the
subject line.

Regards,
ST
--

Re: [Visualpython-users] Borderless window

[Jamie R. <jam...@gm...>]

Stef,
Thanks! That's just what I needed. And on windows no less!
Cheers - jamie

On Sat, Mar 28, 2009 at 4:39 PM, Stef Mientki <s.m...@ru...> wrote:

> for windows:
> http://mientki.ruhosting.nl/data_www/pylab_works/pw_vpython_docking.html
>
> the same trick should work for *nix,
> but I'm no experience with *nix.
>
> cheers,
> Stef
>
> Jamie Riotto wrote:
> > Is there a way to display a VPython window as borderless? Alternately
> > is there any way in general
> > to have VPython display into a window in another application? (If I
> > can display the window as borderless,
> > then at least I can force the VPython window to overlay the underlying
> > app's "graphics" window, and have it
> > appear to be seemless)
> > Thanks - Jamie Riotto
> > ------------------------------------------------------------------------
> >
> >
> ------------------------------------------------------------------------------
> >
> > ------------------------------------------------------------------------
> >
> > _______________________________________________
> > Visualpython-users mailing list
> > Vis...@li...
> > https://lists.sourceforge.net/lists/listinfo/visualpython-users
> >
>
>
> ------------------------------------------------------------------------------
> _______________________________________________
> Visualpython-users mailing list
> Vis...@li...
> https://lists.sourceforge.net/lists/listinfo/visualpython-users
>

Re: [Visualpython-users] Borderless window

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

for windows:
http://mientki.ruhosting.nl/data_www/pylab_works/pw_vpython_docking.html

the same trick should work for *nix,
but I'm no experience with *nix.

cheers,
Stef

Jamie Riotto wrote:
> Is there a way to display a VPython window as borderless? Alternately 
> is there any way in general
> to have VPython display into a window in another application? (If I 
> can display the window as borderless,
> then at least I can force the VPython window to overlay the underlying 
> app's "graphics" window, and have it
> appear to be seemless)
> Thanks - Jamie Riotto
> ------------------------------------------------------------------------
>
> ------------------------------------------------------------------------------
>   
> ------------------------------------------------------------------------
>
> _______________________________________________
> Visualpython-users mailing list
> Vis...@li...
> https://lists.sourceforge.net/lists/listinfo/visualpython-users
>   

Re: [Visualpython-users] Borderless window

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

Within VPython itself there is no control over window details. However, 
you will find in the archives for this list discussions by various 
people in which they (I believe) managed to put a VPython window inside 
another application. Perhaps one of these hardy souls will comment.

Bruce Sherwood

Jamie Riotto wrote:
> Is there a way to display a VPython window as borderless? Alternately is 
> there any way in general
> to have VPython display into a window in another application? (If I can 
> display the window as borderless,
> then at least I can force the VPython window to overlay the underlying 
> app's "graphics" window, and have it
> appear to be seemless)
> Thanks - Jamie Riotto

[Visualpython-users] Borderless window

[Jamie R. <jam...@gm...>]

Is there a way to display a VPython window as borderless? Alternately is
there any way in general
to have VPython display into a window in another application? (If I can
display the window as borderless,
then at least I can force the VPython window to overlay the underlying app's
"graphics" window, and have it
appear to be seemless)
Thanks - Jamie Riotto