Question

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Controller : MonoBehaviour
{
public Rigidbody rb;
public float jumpForce;
public float speed;
public float moveX;
public float moveY;
void Start()
{
if (rb == null)
{
rb = GetComponent<Rigidbody>();
}
}

// Update is called once per frame
void Update()
{
if (Input.GetKeyDown(KeyCode.Space))
{
rb.AddForce(Vector3.up * jumpForce, ForceMode.Impulse);
}
moveX = Input.GetAxis("Horizontal");
moveY = Input.GetAxis("Vertical");
transform.Translate(Vector3.forward * speed * moveY * Time.deltaTime);
transform.Translate(Vector3.right * speed * moveX * Time.deltaTime);
}
}


Make it simple physics based movement instead

Answer 1

Here’s a simple physics-based movement controller that uses the Rigidbody for movement and jumping. It moves by setting the Rigidbody velocity (so collisions and physics behave naturally) and handles jumping in FixedUpdate via a jump-request flag set in Update. It also includes a basic grounded check using collision normals.

Paste this on the same GameObject that has the Rigidbody (make sure the Rigidbody is not kinematic):

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Controller : MonoBehaviour
{
public Rigidbody rb;
public float speed = 5f; // horizontal move speed
public float jumpForce = 5f; // impulse applied when jumping

private float moveX;
private float moveY;
private bool isGrounded;
private bool jumpRequested;

void Start()
{
if (rb == null) rb = GetComponent<Rigidbody>();
}

void Update()
{
// read input in Update for responsiveness
moveX = Input.GetAxis("Horizontal");
moveY = Input.GetAxis("Vertical");

if (Input.GetKeyDown(KeyCode.Space) && isGrounded)
{
jumpRequested = true;
}
}

void FixedUpdate()
{
// Build horizontal movement vector relative to player orientation
Vector3 move = (transform.right * moveX + transform.forward * moveY);
Vector3 horizontalVel = move.normalized * speed;

// Preserve vertical velocity (gravity, jumps) and apply horizontal velocity
rb.velocity = new Vector3(horizontalVel.x, rb.velocity.y, horizontalVel.z);

// Apply jump impulse if requested
if (jumpRequested)
{
rb.AddForce(Vector3.up * jumpForce, ForceMode.Impulse);
jumpRequested = false;
}
}

void OnCollisionEnter(Collision collision)
{
CheckGroundCollision(collision);
}

void OnCollisionStay(Collision collision)
{
CheckGroundCollision(collision);
}

void OnCollisionExit(Collision collision)
{
// Simple approach: when leaving contact, mark not grounded. OnCollisionStay/Enter will set true again.
isGrounded = false;
}

private void CheckGroundCollision(Collision col)
{
// If any contact normal points mostly upward, consider the player grounded
foreach (ContactPoint cp in col.contacts)
{
if (cp.normal.y > 0.5f)
{
isGrounded = true;
return;
}
}
}
}

Tips:
- Make sure the Rigidbody's “Constraints” freeze X/Z rotation if you don't want the player to tip over.
- Consider setting Rigidbody.interpolation = Interpolate for smoother visuals.
- If you want acceleration instead of instant velocity changes, use rb.AddForce with ForceMode.Acceleration or Lerp the velocity toward the target.
- If you want to support double jumps, remove the isGrounded check for jump or add counters.

If you want an alternative that uses rb.MovePosition (kinematic-like smooth movement) or that uses AddForce for acceleration, tell me which behavior you prefer and I’ll provide that version.