How to make enemy walk on walls, while go toward player?

Question

I need to make enemy walk on walls, like a spider, while follow the player. For example, between the enemy and the player there is a box, the enemy instead of avoid this, must walk on, sticking to the walls.

Thanks

Answer 1

I found this question very interesting so decided to have a go. I used this answer by Aldo as a reference : http://answers.unity3d.com/questions/168097/orient-vehicle-to-ground-normal.html

It is far from perfect, and I have only tested it in the attached scene, but see how it goes : http://www.alucardj.net16.net/unityanswers/WalkOnWalls1.unitypackage

what it does is check for 1/ a wall infront of the object and 2/ no floor below object. When either of these conditions are met, a raycast determines the normal of the next surface to walk along, rotates the object to that normal, then keeps on trucking !

Script :

 #pragma strict
 
 var myTransform : Transform;
 var speed : float = 5.0;
 var isWalking : boolean = true;
 var curNormal : Vector3 = Vector3.up;
 var hitNormal : Vector3 = Vector3.zero;
 
 function Start() 
 {
     myTransform = transform;
 }
 
 function Update() 
 {
     switch( isWalking )
     {
         case true :
             // check for wall
             var rayHit : RaycastHit;        
             if ( Physics.Raycast( myTransform.position, myTransform.forward, rayHit, 0.5 ) )
             {
                 hitNormal = rayHit.normal;            
                 isWalking = false;
             }
             Debug.DrawRay( myTransform.position, myTransform.forward * 1.0, Color.red );    // show forward ray    
             
             // check for no floor    
             var checkRear : Vector3 = myTransform.position + (-myTransform.forward * 0.25);
             if ( Physics.Raycast( checkRear, -myTransform.up, rayHit, 1.0 ) )
             {
                 // there is a floor!
             }    
             else
             {
                 // find the floor around the corner
                 var checkPos : Vector3 = myTransform.position + (myTransform.forward * 0.5) + (-myTransform.up * 0.51);
                 Debug.DrawRay( checkPos, -myTransform.forward * 1.5, Color.green );    // show floor check ray
                 if ( Physics.Raycast( checkPos, -myTransform.forward, rayHit, 1.5 ) )
                 {
                     Debug.Log( "HitNormal " + rayHit.normal );            
                     hitNormal = rayHit.normal;            
                     isWalking = false;
                 }
             }            
             Debug.DrawRay( myTransform.position, -myTransform.up * 1.0, Color.red );    // show down ray
             // move forward
             MoveForward();
         break;
         
         case false :
             curNormal = Vector3.Lerp( curNormal, hitNormal, 4.0 * Time.deltaTime );
             var grndTilt : Quaternion = Quaternion.FromToRotation( Vector3.up, curNormal );
             transform.rotation = grndTilt;            
             var check : float = (curNormal - hitNormal).sqrMagnitude;        
             if ( check < 0.001 )
             {
                 grndTilt = Quaternion.FromToRotation( Vector3.up, hitNormal );            
                 transform.rotation = grndTilt;            
                 isWalking = true;
             }
         break;
     }
 }
 
 function MoveForward() 
 {
     myTransform.position += transform.forward * speed * Time.deltaTime;
 }

Answer 2

Answer by dd3kk · Dec 12, 2012 at 11:07 AM

Thank you very much. I am preparing to study this script. I tried it myself first to ask the forum to do some testing with the Raycast. Of course it works, but I have problems with normal that sometimes are out of phase or with the rigidbody for collisions, which causes problems. Unfortunately I am not a professional programmer. I will try to use the script and if there are meanwhile will insert progress.

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Answer 3

Answer by dd3kk · Dec 15, 2012 at 01:53 PM

I finally wrote the script. I extracted from yours, the lines for the rotation. It works fine for now, including follow the player. The single biggest problem is that rotates correctly only when rotated in one direction. If the rotate towards an other face of the cube then rotating the enemy on another axis, just touches the face of the object, in a frame rotates in the wrong direction. I've tried everything. however, I insert here a few frames to explain. I hope it is clear and sorry for the bad english. thanks

this is the code I use for the rotation, but I tried other solutions and it always comes to the same result.

 curNormal = Vector3.Lerp(curNormal, hitZnormal, 6.0 * Time.deltaTime);
     var tiltToNormal : Quaternion = Quaternion.FromToRotation(Vector3.up, curNormal);
     transform.rotation = tiltToNormal;

GOOD - FRONT alt text BAD - RIGHT SIDE

good2touch.jpg (18.9 kB)

bad2touch.jpg (31.0 kB)

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Answer 4

Answer by dd3kk · Dec 16, 2012 at 03:46 AM

Hi! Fortunately, I solved the problem by changing the "Vector3.up" in "transform.up" and adding, outside the brackets the string "* transform.rotation"

here, the code: var tiltToNormal : Quaternion = Quaternion.FromToRotation(transform.up, curNormal)*transform.rotation;

Thanks anyway!

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Answer 5

Answer by rubendariohh · Dec 31, 2017 at 10:43 PM

Can you please share the C# Script?

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How to make enemy walk on walls, while go toward player?

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