[ODEJAVA] Body with Multiple-Geoms problem

nhapentor · January 14, 2007, 12:56pm

I have run MultiGeomTest demo with xith3d as the source below, it worked fine.

Body boxBody = new Body("box", world);

GeomBox b = new GeomBox(4f, 4f, 4f);
boxBody.addGeom(b);
b.setPosition(new Vector3f(0f, 0f, 0f));

GeomBox d = new GeomBox(6f, 6f, 6f);
GeomTransform dt = new GeomTransform();
dt.setEncapsulatedGeom(d);
boxBody.addGeom(dt);
d.setPosition(new Vector3f(0f,-5f,0f));

boxBody.setPosition(10f, 5f, 0f);
boxBody.adjustMass(1f);
space.add(dt);
space.add(b);

Shape3D cube2Shape = new Shape3D(TestUtils.createCubeViaTriangles(0,0,0,4,true,true,true,1f));
TransformGroup cube2TG = new TransformGroup();
cube2TG.addChild(cube2Shape);

boundObjects.add(new BoundDisplayObject(new Xith3DDisplayObject(
    cube2TG), b));

Shape3D boxShape = new Shape3D(TestUtils.createCubeViaTriangles(0,0,0,6,true,true,true,1f));
TransformGroup boxTG = new TransformGroup();
boxTG.addChild(boxShape);

boundObjects.add(new BoundDisplayObject(new Xith3DDisplayObject(
    boxTG), dt));

GeomSphere sphereGeom = new GeomSphere(2f);
Body sphereBody = new Body("sphere", world, sphereGeom);                
sphereBody.setPosition(0.5f, 1.8f, 2.3f);
sphereBody.adjustMass(1f);
space.addBodyGeoms(sphereBody);

Shape3D sphereShape = new Shape3D(TestUtils.createSphere(2f, 40), sphereApr);

TransformGroup sphereTG = new TransformGroup();
sphereTG.addChild(sphereShape);

boundObjects.add(new BoundDisplayObject(new Xith3DDisplayObject(
    sphereTG), sphereGeom));

// Static ground geometry
PlaceableGeom planeGeom = new GeomBox("plane", 100f, 1f, 100f);
planeGeom.setPosition(0.1f, -7f, 0f);
space.add(planeGeom);

Shape3D planeShape = new Shape3D(TestUtils.createRectangleViaTriangles(0,
  0, 0, 100, 1, 100, false, true, true, 1f), planeApr);

TransformGroup planeTG = new TransformGroup();
planeTG.addChild(planeShape);

boundObjects.add(new BoundDisplayObject(new Xith3DDisplayObject(
  planeTG), planeGeom));

geomRoot.addChild(planeTG);
geomRoot.addChild(sphereTG);
geomRoot.addChild(boxTG);
geomRoot.addChild(cube2TG);

But I cannot set the position of the box (GeomBox b) in the boxbody which not encapsulated by the geomtransform.
So I modified the code to encapsulate it in geomtransform as follow :

Body boxBody = new Body("box", world);

GeomBox b = new GeomBox(4f, 4f, 4f);
GeomTransform bt = new GeomTransform();
bt.setEncapsulatedGeom(b);
boxBody.addGeom(bt);
b.setPosition(new Vector3f(0f, 0f, 0f));

GeomBox d = new GeomBox(6f, 6f, 6f);
GeomTransform dt = new GeomTransform();
dt.setEncapsulatedGeom(d);
boxBody.addGeom(dt);
d.setPosition(new Vector3f(0f,-5f,0f));

boxBody.setPosition(10f, 5f, 0f);

// boxBody.setMassParameters(1f,0f,0f,0f,0.01f,0.01f,0.01f,0.01f,0.01f,0.01f);
boxBody.adjustMass(1f);
// space.addBodyGeoms(boxBody);
space.add(dt);
space.add(bt);

Shape3D cube2Shape = new Shape3D(TestUtils.createCubeViaTriangles(0,0,0,4,true,true,true,1f));
TransformGroup cube2TG = new TransformGroup();
cube2TG.addChild(cube2Shape);

boundObjects.add(new BoundDisplayObject(new Xith3DDisplayObject(
    cube2TG), bt));

Shape3D boxShape = new Shape3D(TestUtils.createCubeViaTriangles(0,0,0,6,true,true,true,1f));
TransformGroup boxTG = new TransformGroup();
boxTG.addChild(boxShape);

boundObjects.add(new BoundDisplayObject(new Xith3DDisplayObject(
    boxTG), dt));

...

With the above code I can set the position of box (GeomBox b) but the boxbody did not collide with the planegeom.
I have searched through this forum and found this topic http://www.java-gaming.org/forums/index.php?topic=6146.0
But I still have no idea how to solve this problem.

Please help me.
Thanks

nhapentor · January 21, 2007, 3:06am

There are no any suggestion ?
I’ve got stuck with many problem of ODE,
such as GeomCylinder, Coliision Detection.

If anyone can solve. Please help me.
Are there any forum I can ask?

eMKa · January 21, 2007, 2:21pm

The advice I can give you, is to try and switch to JOODE. It’s a bit more active than ODE… and pure Java !

irrisor · January 21, 2007, 3:11pm

well, this is a joke, isn’t it? ok, t_larkworthy showed up again and two new people have been working on it a little bit, but it’s really not that active. And ODE seems to be really active these days… Or are you talking about ODEJava? Then you’re right - seems to be quite dead :’( (william seems to be the person in charge, and it seems he has other things to do)

nhapentor, ODEJava does not support the cylinder (without caps) primitive. JOODE does not support it either. You should be able to sort out these placement problems though…

If you want a better supported ODE binding (with working cylinder and easy placement) you can try jME Physics 2, but this would require you to use jME, which might not be an option. jME Physics 2 board can be found here.

eMKa · January 21, 2007, 5:13pm

ODE.activity > JOODE.activity > ODEJava.activity

Is it clearer ?

irrisor · January 22, 2007, 8:01am

hehe, kk

eMKa · January 22, 2007, 5:16pm

sometimes some code is worth a thousands natural-language words

nhapentor · January 23, 2007, 3:44pm

Thanks Amos & irrisor.

Amos, I just begin to study joode ( when I got stuck with odejava ) and it’s seem like irrisor said ( it’s not really active ).

irrisor , It’s bad news that cylinder does not support in both odejava & joode but thanks for your advice to jME. I will begin to look at it.

Anyone, Are there another way that I can create a complex geom to be a robot joint ?

At first I import model from .3DS as GeomTrimesh in odejava but there are problems about collision.

Then I think about multi-geoms body, so I try to use basic geom such as box and cylinder but they don’t work. I cannot define the position of each in multi-geoms bodies. Moreover the cylinder doesn’t support. Although I try to use GeomCappedCylinder instead it’s seem that not work too.

So I have no idea to continue. I got stuck with physics engine for a very long time.