Which plane is which with CalculateFrustumPlanes

Questions & Answers
1

I understand that CalculateFrustumPlanes() in Unity3D returns an array of Plane objects, each representing a different frustum plane, but I can’t find any documentation to suggest which element is which?

for example

[0] = Front [1] = Back

etc.

I need to calculate whether a point in space (like the centre point of a Bounding volume) is in the camera frustum, for a Quad tree system.

3

I got this arrangement:

[0] = Left
[1] = Right
[2] = Down
[3] = Up
[4] = Near
[5] = Far

All normals point towards the inside of the frustum

2

The answer proved by AlwaysSunny above recommends checking the normal of each plane against the camera’s forward.

Unfortunately, the near and far planes have the same forward :frowning:

The easiest solution I have found is to move each plane along the normal. Then I look at the location of the plane relative to the camera’s position while the camera is at a zeroed rotational position:

GameObject[] frustumBounginObjects = new GameObject[6];
public void CreateScreenBoundingObjects ()
{
	Camera cam = Camera.main;
	Plane[] frustumPlanes = GeometryUtility.CalculateFrustumPlanes(cam);       

	for (int i=0; i < frustumPlanes.Length; ++i)
	{            
		frustumBounginObjects *= GameObject.CreatePrimitive(PrimitiveType.Plane);*

frustumBounginObjects.transform.position = -frustumPlanes_.normal * frustumPlanes*.distance;
// Which plane?
if(frustumBounginObjects.transform.position.y > 0) // Top?
{
frustumBounginObjects.name = “Top”;
}
else if(frustumBounginObjects.transform.position.y < 0) // Bottom?
{
frustumBounginObjects.name = “Bottom”;
}
else if(frustumBounginObjects.transform.position.x > 0) // Right?
{
frustumBounginObjects.name = “Right”;
}
else if(frustumBounginObjects.transform.position.x < 0) // Left?
{
frustumBounginObjects.name = “Left”;
}
else if(frustumBounginObjects.transform.position.z > Camera.main.nearClipPlane) // Far?
{
frustumBounginObjects.name = “Far”;
}
else // Near?
{
frustumBounginObjects.name = “Near”;
}*_

_ frustumBounginObjects*.name += "Plane ";
}
}*_

4

The answer to this question is now described in the unity documentation , including a script that creates planes in the correct positions. Either way the answer from @MrEastwood is correct so you should mark it as solved.