3D - Object rotates and jumps weirdly when moving from point A to point B

Questions & Answers
1

I am trying to make a simple 3D Tank game, where the enemy tanks go from one random coordinates to another. When they spawn, they are aligned to the ground, like this

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And most of them move around just fine, but sometimes they start rotating up when moving forward, and then they get like this, and start jumping up and down

51048-c2.jpg
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What could be the reason for this, they are not colliding with anything that would interfere with their movement?

if I need to provide more info, please ask

EDIT: Here’s the script for movement

void MoveToTarget() {
		transform.position = Vector3.MoveTowards(transform.position, targetCoords, moveSpeed * Time.deltaTime);
        transform.LookAt(targetCoords);
	}
2

The problem happens if the coordinates for lookat has a different y-value than the object. This is easy to fix. Replace this:

transform.LookAt(targetCoords);

with:

Vector3 targetAtHeight = targetCoords;
targetAtHeight.y = transform.position.y;
transform.LookAt(targetAtHeight);

This will cause your tanks looking at behaviour to be 2D only.

3

To keep the LookAt method from affecting the x and z rotation, you can construct a new Vector3 with X and Z coordinates from the target and the Y coordinate from the enemy itself.

Vector3 targetVector = new Vector3(target.transform.position.x, this.transform.position.y, target.transform.position.z);
        transform.LookAt(targetVector);

This will keep the tank from tilting when moving as the target always is on the same y-position as itself.

To keep it from jumping you could also lock the y-position of the rigidbody component, but i would suggest looking at wheel colliders instead. I think you can eliminate all these problems by adding “wheels” to your tank. Unity - Manual: Create a vehicle with Wheel Colliders