Collide tag problem

I’m trying to make collision response with landscape mesh using tag
{ Polyset keep descend } ,but when I load my model with this tag and using such code:

base.cTrav=CollisionTraverser()
self.pusher = CollisionHandlerPusher()
self.model=loader.loadModel(filename)
self.model.wrtReparentTo(render)
self.model.setTwoSided(False)
self.cNode=self.model.find("**/+CollisionNode")
base.cTrav.addCollider(self.cNode,self.pusher)
self.pusher.addCollider(self.cNode,self.model, base.drive.node())

, panda writes to console such message:

“This means that a CollisionPolygon object was added to a
CollisionTraverser as if it were a colliding object. However,
no implementation for this kind of object has yet been defined
to collide with other objects.”

But as we know,Roaming Ralph demo works successfully with this tag and it has collision response.So where is the mistake and how to make mesh collision with this tag?

You must set the “into” mask of the collision polygon, not the “from” mask (which must be 0).