Unity Physics.Raycast does not detect an object when it should

user_15684943 0
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I am making a 2D game and I am using Raycast to detect if the player is on the ground. No matter what Raycast always returns false. I have used Debug.DrawRay which shows that the ray is hitting the ground. I have tried solutions from several different tutorials but nothing worked. I am pretty new to Unity so hopefully someone who is more experienced knows what's wrong.

 if (Physics.Raycast(transform.position, transform.TransformDirection(-Vector3.down), DistanceDown, LayerMask)){
        Debug.Log("Grounded");
        return true;
    }
    else
    {
        Debug.Log("Not Grounded");
        return false;
    }

Revised Code:

if (Physics.Raycast(transform.position, transform.TransformDirection(Vector3.down), (float)(GetComponent<Collider2D>().bounds.extents.y + Offset)))
unity3d c#
1 Answers

A Raycast has a few parameters. I will explain each as there could be a few reason as to why it is not working, so possibly breaking this up can help you realize what's wrong.

Raycast(Vector3 origin, Vector3 direction, float maxDistance = Mathf.Infinity, int layerMask = DefaultRaycastLayers, QueryTriggerInteraction queryTriggerInteraction = QueryTriggerInteraction.UseGlobal);

The origin is the point in space that the ray will start from. Currently, you have it as transform.position, so it will start at the position of whatever the script is on, most likely your player.

The direction is a vector that should be normalized so there is no scale to determine where from the origin the ray should be cast. Right now you are using -Vector3.down, which would result in Vector3.Up as up and down are opposites, so negating one gives the other. For a ground check, I would be using Vector3.down as the ground is generally down or below the origin of your player.

The maxDistance is the length that the ray is cast. Right now you have it as DistanceDown which I am assuming is some float. Generally, for a ground check, I would take the collider of your character, then add some offset to determine when grounded. Something along the lines of GetComponent<Collider>().bounds.extents.y + OFFSET. The bounds.extents.y is half the size of the collider and since your origin is the center of your player, this should land at the feet or base of your collider, which is why you need the offset.

The layermask is used to ignore particular layers when casting. It is rather useful when you only want to cast and hit a single layer, where in your case could just be the ground. I do not see code for this, but I will provide an example in case this is where you are going wrong. LayerMask mask = LayerMask.GetMask("GroundLayer"); and use mask as your mask. Now the ray will only hit objects on the layer GroundLayer.

The last parameter which you are not using is called queryTriggerInteraction. Raycast by default do not hit triggers, but with this parameter, you can override it and tell it to hit triggers.

Read over each of these sections and check to make sure what you are doing matches what I am describing. If you are still unable to figure out your issues based on what I have written, I would need to know a bit more about your situation to help out.

user_36574490
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