Re: [Pyode-user] Pyode binary distribution

[<al...@ci...>]

Hello,

I found the problem, see the attached file.

Somewhere in the code, there is a line:

# create a list to store any ODE bodies which are not part of the ragdoll (this

# is needed to avoid Python garbage collecting these bodies)

bodies = []


A similar code snippet is needed for geoms, too. That's why I added the following:
geoms = []


And after creating every geom, I have added it to that list. That solved the
problem.

"bodies" and "geoms" are not used anywhere in the code. They just say to
Python's garbage collector: I'm using these objects, do not delete them.

When there are no more references to a body or a geom, PyODE removes those objects
from ODE simulation automatically. That happened into your code: bodies were still
present in simulation (that's why the doll was falling), but all the geoms
(floors and capsules) were deleted.

Is the ragdoll example the one from
http://monsterden.net/software/ragdoll-pyode-tutorial ?
I think it would be nice to include it in the PyODE examples folder.

Alex

> Hello Alex,
>
> Thanks for your note and recommendations. I have answed them one by one,
> next to your questions:
>
> Kadir
>
> 2010/3/27 <al...@ci...>
>
>> Hello,
>>
>> First thing you should check:
>> Do the examples from C:\Python26\pyode-examples run correctly?
>>
>> >>> Tutorial 1 runs OK, with the same numerical output
>>>> Tutorial 2 runs OK with same double pendulum swinging
>>>> Tutorial 3 runs with the same problem I had with new installation of
> PyODE. Boxes falling down, penetrating the floor (plane).
>
>
>> tutorial3.py has an example with a GeomPlane some falling boxes and
>> spheres.
>> Does it run correctly?
>>
>
>>>> Tutorial 3 runs with the same problem I had with new installation of
> PyODE. Boxes falling down, penetrating the floor (plane).
>
>
>> I have just tested it with a fresh install of Python 2.6, PyOpenGL 3.0.1
>> and
>> PyODE-snapshot-2010-03-22.win32-py2.6.exe.
>> It worked from the first try.
>>
>> Which version of ODE do you use on Python 2.5? It seems that different ODE
>> versions behave slightly differently
>> with the same scene description.
>>
>> >>>> I believe PyODE 1.2.0, which was installed using
> PyODE-1.2.0.win32-py2.5.exe.
>
>
>> Do you use PyODE directly from your program or do you have some higher
>> level
>> library, like cgkit?
>> In the second case, please check that it uses the same stepping method
>> (step or
>> quickStep) in both Py25 and 26.
>>
>> >>>> I use it directly. I use Vpython for visualisation.
>
>
>> Can you send me a small test program, with the floor and one body, which
>> works
>> in Py25 and not in 26?
>>
>
>>>>> I am attaching one famous RagDoll I have been using with PyODE. It is
> supposed to fall and lie down on the floor.
> Although I know nothing about robotics, I am trying to get this RagDoll up
> and walking.
>
> I have visited your robot site.  I have downloaded the windows version of
> your robot and ran it on my laptop. I liked it very much. I tried to
> implement a similar kinematic robot arm earlier, I had some coordination
> problems, then I was planning to migrate it to ODE as a dynamic arm. I use
> VPython for visualization, not OpenGL since VPython is very easy to use.
>
>>
>> I am also using PyODE in a simulation which involves bodies sitting, and
>> sometimes falling, on the ground.
>> When the gravity, body mass or vertical speed were too high, they could
>> break
>> the floor and fall down.
>> So you may start debugging with reducing the gravity value.
>>
>> >>> I set g = -0.81, same behaviour, slow-motion.
>
> It looks like a collision detection problem but where? Any double Precision
> / SÝngle Precision issue?
>
>
>> However, the simulation runs exactly the same in Py25 and 26, with exactly
>> the
>> same code. I do not use
>> PyODE directly, but all the rendering and simulation is done using cgkit.
>> I'm
>> using boxes and trimeshes,
>> and sometimes spheres for debugging.
>>
>> The program in which I use PyODE is a robot arm simulator, still in early
>> stages
>> of development, available here:
>> http://github.com/alexdu/robot-sandbox . For now, it only runs on Windows
>> out of
>> the box (unzip and run).
>>
>> > Hi again,
>> >
>> > I have installed Python 2.6.4 and tried to install PyODE on top. I have
>> > downloaded the
>> > PyODE-snapshot-2010-03-22.win32-py2.6.exe<
>> http://sourceforge.net/projects/pyode/files/pyode/snapshot-2010-03-22/PyODE-snapshot-2010-03-22.win32-py2.6.exe/download
>> >from
>> > the sourceforge and somehow got it working :))
>> >
>> > But now funny things are happening. It looks like the GeomPlane is not
>> > functioning correctly, so that everything falls down forever. My "floor"
>> has
>> > gone. The same exact code works OK in Python25, in 2.6, the rest seems OK
>> > for the moment (At least gravity is there, joints are working, bodies are
>> > working OK), but the floor is gone!?
>> >
>> > Is it a collision detection problem, although for the remaining parts it
>> > seems to work ok. Bodies are mostly CappedCylinders (plus some spheres).
>> >
>> >>From Idle, I can see ode.GeomPlane is in there, but somehow it is not
>> > working OK.
>> >
>> > I will check with some other programs, or simple geometries.
>> >
>> > Thnaks for your work and support.
>> >
>> > Kadir
>> >
>> > 2010/3/23 Ethan Glasser-Camp <gl...@cs...>
>> >
>> >> al...@ci... wrote:
>> >> > I have tried to create a binary Win32 installer for latest PyODE
>> >> snapshot.
>> >> > I am sure Kadir and others will find it useful.
>> >>
>> >> This is awesome, thanks!
>> >>
>> >> I have uploaded this, as well as tarballs taken from today's git, to the
>> >> files section of the sourceforge project:
>> >>
>> >> https://sourceforge.net/projects/pyode/files/
>> >>
>> >> I've elected to use a snapshot-ymd system, since at present the project
>> >> doesn't have "features" that are added in any regular fashion.
>> >>
>> >> I also updated the project website with the git URL and links to the
>> >> most current files.
>> >>
>> >> > Since I'm a beginner in creating Python packages, I have two small
>> >> issues:
>> >> >
>> >> > 1. The installer copies "ode.dll" to c:\python25. Is this a problem?
>> >> > I believe it should be copied into "site-packages" instead, but I did
>> not
>> >> know
>> >> > how to
>> >> > specify this in setup.py.
>> >>
>> >> No idea here, sorry..
>> >>
>> >> > 2. The examples are copied into c:\python25\pyode-examples. Is there a
>> >> better
>> >> > choice?
>> >>
>> >> I wouldn't include them at all, frankly.
>> >>
>> >> > 3. When installing the binary package to a fresh Python directory,
>> >> tutorials 1
>> >> > and 3
>> >> > work fine; the others need pygame and maybe cgkit. Is there a way to
>> >> specify
>> >> > these dependencies in the binary installer?
>> >>
>> >> I think it's fine to leave these out -- not all people who use ODE are
>> >> going to want to use it with Pygame.
>> >>
>> >> > I have added examples and ode.dll as "data_files" in setup.py. I would
>> >> also like to
>> >> > see the setup.py which created the releases from
>> >> pyode.sourceforge.net(1.2.0).
>> >>
>> >> I would guess that the setup.py in the source tree is the one they used,
>> >> but I have no idea.
>> >>
>> >> Ethan
>> >>
>> >>
>> >>
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>>
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