Keep car above the ground

General Discussion
1

I have a car and a track.

I would like my car to always be positioned above the trak.

How do I do this using a ray ?

Please post code if possible.

2

Same code you’d use for a car going uphill :wink:

Here is some quick code, its a bit more complicated then your previous questions so the best way is to read it through and understand why I did what, then write your own version that suits your need.
This atleast handles the collision part, I guess you’d have to adjust the cars hpr in there aswell.

Edit: I’m not a mod here, but I think these questions fit in the “scripting issues” forum, not “general discussion”.

  • Good luck

class World(DirectObject):

    def __init__(self):
        self.loadWorld()
        self.gameTask = taskMgr.add(self.gameLoop, "gameLoop")
        self.gameTask.last = 0

    def gameLoop(self, task):
        dt = task.time - task.last
        task.last = task.time

        #If dt is large, then there has been a hiccup that could cause the player
        #to leave the field if this functions runs, so ignore the frame
        if dt > .2: return Task.cont

        # get the collision entries, and act accordingly
        for i in range(self.cHandler.getNumEntries()):
          entry = self.cHandler.getEntry(i)
          name = entry.getIntoNode().getName()
          if   name == "Terrain":   self.groundCollideHandler(entry)

    def groundCollideHandler(self, colEntry):
        #Set the player to the appropriate Z value for it to be exactly on the ground
        newZ = colEntry.getSurfacePoint(render).getZ()
        if newZ - self.player.getZ() > 2:
            self.player.bump()
        else:
            self.player.setZ(newZ+.4)

    def loadWorld(self):
        # load visible geometry
        world = loader.loadModel("models/leafBay")
        world.setScale(0.12)
        world.reparentTo(render)

        # load unvisible collision geometry
        solids = loader.loadModel("models/leafBay_coll")
        solids.setScale(0.12)
        solids.reparentTo(render)

        # find collision group "Terrain" and set collideMask bit 1
        terrain = solids.find("**/Terrain")
        terrain.node().setIntoCollideMask(BitMask32.bit(1))

        #################################
        ## setup collisions
        ##
        
        # create the collision ray
        ray = CollisionRay()
        ray.setOrigin(0,0,50)
        ray.setDirection(0,0,-1)
        
        # set bitmask and stuff
        rayNode = CollisionNode('groundRay')
        rayNode.addSolid(ray)
        rayNode.setFromCollideMask(BitMask32.bit(1))
        rayNode.setIntoCollideMask(BitMask32.allOff())

        # attach the rayNP to the player
        actor = self.player.getActor()
        rayNP = actor.attachNewNode(rayNode)
        # uncomment next line to view the ray
        #rayNP.show()
        
        # add collision nodes to a collision handler
        self.cTrav = CollisionTraverser()
        self.cHandler = CollisionHandlerQueue()

        self.cTrav.addCollider(rayNP.node(),self.cHandler)
        # uncomment next line to show collisions
        #self.cTrav.showCollisions(render)
        base.cTrav = self.cTrav