[ODE] Plane-Cylinder collision: not good in 0.7, worse in SVN :(

[Bram Stolk]

Hi,

It turns out that I was caught off-guard by the difference between

dReal dGeomPlanePointDepth (dGeomID plane, dReal x, dReal y, dReal z);

and

dReal dPointPlaneDistance(const dVector3& point,const dVector4& plane);
...which was part of the cyl2 contrib code, but does not do what I expect.

I'll try to replace the funcs, and see what happens.

  Bram


On Sat, 2006-10-28 at 10:30 +0200, Mauro G. Todeschini wrote:

> I discovered that the problem not only happens for transformed
> cylinders, but even between "normal" cylinders and planes. If in
> test_cylvssphere.cpp you only change line 185 from:
>   dCreatePlane (space,0,0,1,0);
> to:
>   dCreatePlane (space,0,0,1,-1);
> You can reproduce the problem.
> 
> Thanks again and Bye
> 
> > 
> > 
> >    Bram
> > 
> > 
> > -----Original Message-----
> > From: "Mauro G. Todeschini" <mauro2006todeschini at itia.cnr.it>
> > To: "Bram Stolk" <bram at sara.nl>
> > Cc: "'ode-list mailing_list'" <ode at q12.org>
> > Sent: 10/28/06 8:20
> > Subject: Re: [ODE] Plane-Cylinder collision: not good in 0.7, worse in SVN :(
> > 
> > Bram Stolk wrote:
> >> For me, cyl vs plane is OK for both geomoffset and trf geoms.
> >>
> >> Could you please do this test against svn-tree?
> >>
> >> - Run test_boxtest and press 'y' a few times.
> >>
> >> - Edit test_boxstack.cpp and change line 94 to:
> >> #define USE_GEOM_OFFSET 0
> >>   Rebuild, and re-run the test.
> >>
> >> For me, both cases are OK.
> >> I just tested this with current svn, on linux, with double prec.
> > Ok, the test you suggested works correctly in both cases but... I think
> > that changing the #define doesn't make any difference for cylinders (ie.
> > trf geoms are never used for cylinders). It only makes difference for
> > composite objects (which don't contain any cylinder, only capsules).
> > Try putting a printf after line 455 and You'll see that you never pass
> > from that line with cylinders.
> > 
> > In my application I discovered that the problem with planes and
> > transformed cylinders seems to happen when I define my plane like this
> > (gravity is dWorldSetGravity (world,0,-9.8,0);):
> > 
> > dCreatePlane (space,0,1,0,-20);
> > 
> > but the problem seems to disappear if:
> > 
> > dCreatePlane (space,0,1,0,0);
> > 
> > I think that the negative value in the first definition has something to
> > do with the problem.
> > 
> > Bye and Thanks
> > 
> >>  Bram
> >>
> >>
> >>
> >>
> >> On Fri, 2006-10-27 at 18:09 +0200, LR wrote:
> >>> Hi Mauro,
> >>>
> >>> I have similars problems with cylinder & transform geoms (it's with the
> >>> sphere/cylinder). To resolve it, i made a compile switch witch enable me to
> >>> compile with "transform geoms" or with "GeomOffsets".
> >>>
> >>> Using geoms offsets solves the cylinder problems (but why ????). 
> >>>
> >>> LR
> >>>
> >>>
> >>>  
> >>>
> >>> -----Message d'origine-----
> >>> De : ode-bounces at q12.org [mailto:ode-bounces at q12.org] De la part de Mauro G.
> >>> Todeschini
> >>> Envoyé : vendredi 27 octobre 2006 15:58
> >>> À : ode-list mailing_list
> >>> Objet : [ODE] Plane-Cylinder collision: not good in 0.7, worse in SVN :(
> >>>
> >>> Hi,
> >>> 	today I downloaded ODE trunk from SVN to test the latest patches for
> >>> collisions between cylinder and plane. In ODE 0.7 there is some problem
> >>> (explosion) when the cylinder falls with a circular face parallel to the
> >>> plane (ground).
> >>> In SVN the explosion happens everytime a cylinder hits a plane (not only on
> >>> its circular face).
> >>> In my tests cylinders are transformed with geomTransforms.
> >>> I read in the mailing-list that there has been some work on the issue
> >>> (cylinder-plane collision) at the beginning of september, but I fear that It
> >>> has not been tested the case of cylinders in geomTransform.
> >>> Has anyone verified the behaviour of cylinders in geomTransforms recently
> >>> (after the changes)?
> >>>
> >>> Thanks and Bye
> >>>
> >>> _______________________________________________
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> >>> ODE at q12.org
> >>> http://q12.org/mailman/listinfo/ode
> >>>
> >>>
> >>>
> >>>
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> > 
> > 
>