Cant add Torque and Rotation to a rigidbody in the same frame?

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Hi guys, could really do with some expert help here as I'm tearing my hair out with this! I cant find any other help articles which address this problem, so hopefully I'm overlooking something very simple.

Basically, I'm writing a top-down helicopter TPS (think Desert Strike). So far its going really well and I have a great model which flies around using proper physics and feels very real.

In each FixedUpdate I'm getting the 3 input axes (pitch, yaw, roll (the axes around x y z respectively)) and then calling my moveplayer method. This applies forces along x and z (y is constrained in the rigidbody settings) and applies a torque around y. So far it works beautifully.

Here's where the problem starts: I want to tilt the helicopter in the direction of travel, but when I apply any sort of rotation command to x or z to pitch or roll (x or z) it works but the torque command stops working so the player can't rotate left or right. Where am I going wrong?

Here's the gist of my code:

     void FixedUpdate ()
     {
             // Get pitch input (-1 to 1)
             float pitch = Input.GetAxis ("Vertical");
 
             // Get yaw (turn) input (-1 to 1)
             float yaw = Input.GetAxis ("Horizontal");
 
             // Get roll input (-1 to 1) - Keys Q & A
             float roll = Input.GetAxis ("Roll");
 
             // Move player
             MovePlayer (pitch, yaw, roll); 
     }
 
 
     void MovePlayer (float pitch, float yaw, float roll)
     {
         // move helicopter in pitch direction
         playerRigidbody.AddForce (transform.forward * pitch * thrust);    
 
         // turn helicopter in yaw direction
         playerRigidbody.AddTorque(transform.up * yaw * 100);
 
         // move helicopter in roll direction
         playerRigidbody.AddForce (transform.right * roll * thrust);
 
         //Clamp helicopter speed
         playerRigidbody.velocity = Vector3.ClampMagnitude (playerRigidbody.velocity, maxSpeed);
 
         // tilt helicopter in pitch direction - enabling this line stops rotation working!
         transform.Rotate (transform.right, pitch*20);
 }

I would be VERY grateful if anyone can help me. I've certainly had a lot of help from reading existing answers so far.

Cheers, Dave

Answer 1

Best Answer

Answer by orchard800 · Sep 20, 2015 at 03:49 AM

OK, I've sussed it myself! Here's the solution for anyone interested. (There's certainly nothing out there about this).

     // tilt helicopter 
     pitchRot = pitchInput * 10f; // pitchInput is vertical input axis
     rollRot = rollInput * 10f;  // rollInput is horizontal input axis
     transform.localEulerAngles = new Vector3(Mathf.Clamp (pitchRot, -20, 20), transform.localEulerAngles.y, Mathf.Clamp (-rollRot, -20, 20));

This allows addtorque to be applied around the Y axis.

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Answer 2

Answer by hexagonius · Sep 19, 2015 at 09:36 PM

add all forces and torques together and apply them only once. they get overridden this way.

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orchard800 · Sep 19, 2015 at 10:20 PM 0

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Ah great! Thanks for the advice. I have merged the 2 AddForce expressions together as suggested. It works just the same but it is neater and probably more efficient. I still cant rotate or use rotation or localrotation or eulerAngles (and so on) whilst toque is being applied though.

To clarify, I can tilt the helicopter back and forth using:

 // pitch helicopter -20 to 20 degrees using
 transform.localRotation = Quaternion.AngleAxis(pitchInput*20, Vector3.right);
 // OR
 transform.Rotate (transform.right, pitch*20);

but cannot add pitch AND roll (around Z) without freezing Y rotation (so torque stops being applied.)

Any ideas?

Cant add Torque and Rotation to a rigidbody in the same frame?

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