Climbing walls

Hi,
I am trying to create mech-spider thing, that can climb walls. Does anybody know how to to do that?? I dont want any kind of dynamic animation system like in other threat about spider dynamic animations. What I need is a simple ellipsoid collision, whose y-axes points in the same direction as normal vector of surface his crawling on. But I dont know how to "get" surface normal, nor how to handle (vertical) corners where it can touch 2 (or more) surfaces at a time.

Any suggestion is welcome.
thanks

Newton returns normal to surface when raycasting as i remember correctly.

I was thinking of Collision Callback, isnt there a normal vector too?? The problem is I have to create that callback for every material pair, which is very exhausting. Isnt there some option to call the callback for any collision for any material?

Raycasting is, I thing, very expensive, I would have to create more than one cast, because I need to track the surface it is crawling on and a surface in front of it (ie. from horizontal surface to vertical surface, corners...).
But I dont know it that well, so if you can help me little further with this, it would be great!

thanks

When a collision is detected the function onAABBOverlap is called. In this function you can choose to call or no the real callback for collision : contactsProcess (return 1 to continue and 0 to stop callback for the pair of bodies).
In contactsProcess you can take the type of you body and doing somthing different in function of type.

For exemple :

CallbackCollision::contactsProcess( OgreNewt::ContactJoint &p_ContactJoint, Ogre::Real p_TimeStep, int p_ThreadIndex)
{

if((p_Body0->getType()==2) || (p_Body1->getType()==2))
return 1;
else
return 0;

}

CallbackCollision::contactsProcess( OgreNewt::ContactJoint &p_ContactJoint, Ogre::Real p_TimeStep, int p_ThreadIndex)
{

if((p_ContactJoint.getBody0()->getType()==2) && (p_ContactJoint.getBody1()->getType()==2))
{
// do something
}

if((p_ContactJoint.getBody0()->getType()==2) && (p_ContactJoint.getBody1()->getType()==0))
{
// do something else
}
...
}

This is featured in Newton 2.0, am I not right?
Damn, I got to upgrade it...

thanks, I will look into it

Yes it's in Newton 2.0 but they are an equivalent in 1.53 version :

ContactCallback::userBegin() equivalent to onAABBOverlap
and ContactCallback::userProcess() equivalent to contactsPorcess

but I don't use this version so I don't know how to keep bodies in functions.

And I see I've done an error in the precedent exemple the first function is :
CallbackCollision::onAABBOverlap( OgreNewt::Body* p_Body0, OgreNewt::Body* p_Body1, int p_ThreadIndex)
{

if((p_Body0->getType()==2) || (p_Body1->getType()==2))
return 1;
else
return 0;

}

and the second :
CallbackCollision::contactsProcess( OgreNewt::ContactJoint &p_ContactJoint, Ogre::Real p_TimeStep, int p_ThreadIndex)
{

if((p_ContactJoint.getBody0()->getType()==2) && (p_ContactJoint.getBody1()->getType()==2))
{
// do something
}

if((p_ContactJoint.getBody0()->getType()==2) && (p_ContactJoint.getBody1()->getType()==0))
{
// do something else
}
...
}

ok, I got it.
But those callbacks are possible to create only with material pairs, no?
I have to do it for all material pairs (but that means I have to specify this callbacks for all pairs - coded one by one)

Isnt there possibility to create callback for all collisions for all materials with one call??

Yes, you can call the same callback for all your material pair and do in the function like my exemple a switch on types of bodies.
But you must indicate for each materalPair the new Callback even it's the same for all. But it's just a much line by materialPair

Excuse me for my english and if I don't understand sometimes that you wants