Question Help with boxcast and visualization?

I've been looking into using a boxcast and its the first time I've used one. I am trying to create a box with center 1 X unit in front of the player , with dimensions 3f ->X, 1f -> Y, 1f -> Z so that it forms a rectangle.

This is the code I've used and it seems to be very wrong. But I can't understand why:

Code (CSharp):

1. mHit = Physics.BoxCast(transform.position + transform.forward,new Vector3(1.5f,.48f,.5f), transform.position,out mHitDetect,Quaternion.identity,1f);
2.  
3.  
4. Gizmos.DrawWireCube(transform.position + transform.forward * mHitDetect.distance, new Vector3(3f,.8f,1f));
5.            

 

Your boxcast arguments are all wrong:

Code (CSharp):

1. mHit = Physics.BoxCast(transform.position + transform.forward,new Vector3(1.5f,.48f,.5f), transform.position,out mHitDetect,Quaternion.identity,1f);
2.  

According to https://docs.unity3d.com/ScriptReference/Physics.BoxCast.html it's:

public static bool BoxCast(Vector3 center, Vector3 halfExtents, Vector3 direction, Quaternion orientation = Quaternion.identity, float maxDistance = Mathf.Infinity, int layerMask = DefaultRaycastLayers, QueryTriggerInteraction queryTriggerInteraction = QueryTriggerInteraction.UseGlobal);

So you've got:

transform.position + transform.forward

for the center, which makes no sense. It should probably just be

transform.position

.
You've got

transform.position

for the direction, which makes no sense. It should probably be

transform.forward

 

I think my understanding of Transform.Forward is wrong then. The way I understood it was that transform.forward represents 1 unit infront of the vector you are facing. So of you're facing at rotation (0,0,0) then the transform.forward is (1,0,0). I imagine that is not correct. What then does transform.forward represent? Does it have a value


I think I got confused as well with Boxcasting. I know think what is happening is that the box is generating and then moving out at a distance. Which is not what I was after. I realized later that I was after an OverlapBox rather than a boxcast.

My understanding now is that if I rotate my character and use the following this will always work?
Physics.OverlapBox(transform.position + transform.forward, new Vector3(size of box based on rotation), Quaternion.identity);

 

transform.forward is a direction vector. It is the direction your object is facing. The position of the object is irrelevant for transform.forward.

If your object is facing along the world forward(z) axis, then it's (0, 0, 1).
If your object is rotated 180 degrees on the y axis from there, it will be (0, 0, -1).

This will work to check a box that is centered 1 unit in front of the character. I'm not sure what you mean by "size of box based on rotation" though. Why would the size of the box be based on the rotation?

 

Ok good. Then I do understand it. Yes I want my box to check one unit in front of the character.

as for Size of Box based on rotation, apologies I should have made my meaning clearer, thats entirely my bad.

What I mean is the size is of type Vector3, so if I am rotated 90 or 270 degrees, then the box will be length wise towards the character instead of what I was aiming for. so i switch the X/Z values based on the rotation of the character. Is there a better way to do that?

Otherwise thank you so much for your assistance. I read through the Unity documentation but I find it to be a bit confusing so didnt really understand it 100%

 

As per the docs (https://docs.unity3d.com/ScriptReference/Physics.OverlapBox.html): OverlapBox has a

Quaternion orientation

parameter. This is how you define how the box is rotated. You would not modify the size for this purpose.