bounding box intersection

Axis-aligned bounding boxes (AABBs) are universally used to bound finite objects in ray-tracing. This returns a Boolean that is set to true if there is an intersection between bounds.

Computing Intersection over Union can therefore be determined via: Figure 2: Computing the Intersection over Union is as simple as dividing the area of overlap between the bounding boxes by the area of union (thank you to the excellent Pittsburg HW4 assignment for the … :)Does anyone know why this doesn't seem to work in GLSL for all angles?What do you mean "doesn't work"?

Any suggestion/algorithm, kindly email me.Having read both this and part 2, I'm unable to work out what changes I need to make in order to reliably detect intersections when a ray is exactly on the edge of an AABB.

Does ray intersect this bounding box? Thank you for the write-up in both articles. So I know if it was a hit if tmax >= tmin AND tmax >= 0. They use things(slow things) like square roots, DOT products and lots of checks with points. or box->origin - center_of_hit_side ? You can keep track of which slab is intersecting in the above algorithm at all times, but that slows it down.For a cube centered at the origin, a neat trick is to take the component of the intersection point with the largest absolute value.The cube trick does not require sorting, just selecting the max from three candidates.So if I return a vec3 with tmin, tmax and a float hit = step(tmin,tmax)*step(0,tmax), I basically know that if hit > 0 then ro+rd*tmin is my lower bound intersection point (entry point) and ro+rd*tmax is my higher bound intersection point (exit point), right?

now my raycasting method has the speed i wanted. not because of the !

a circle, an ellipse, an arbitrary shape)? This is worth another post actually, I'll write one up.Thanks for posting this (so long ago)! The bounding boxes of two objects can intersect even if the objects themselves don't actually intersect. I know each side has its own. The predicted bounding box is drawn in red while the ground-truth (i.e., hand labeled) bounding box is drawn in green. Then we also know tmin is the closest intersection and tmax is the furthest.I implemented this in C++ and it works perfectly for any ray direction.

Generally, when performing clash detection, you will always run a super fast pre-processing step first to determine candidate elements, and then narrow down the search step by step more precisely in following steps. Note that the results are – by design – coarse, as the input element Outlines … You don't have to square it.I know this is from a couple of years but ago now, but I’m really confused by this.You say you can calculate the inverse of a ray with (1/x, 1/y, 1/z) but I don’t understand that.Suppose I had a ray going straight in the x direction (1,0,0). But the bounding box is always paralell to the axis X, Y and Z and this may cause a problem, like return elements that are not really clashing, because sometimes the bounding box it's not always coincident with the geometry because the family instance is rotated. Featured on Meta Are you sure there are none missing?

I can't see that gist though (says "OAuth failure"). //Attach this script to an empty GameObject. I used this in my own code, and wondered if it is possible to save 2 of the subtractions by taking advantage of the fact that min(x+a, y+a) = min(x,y)+a (for some constant a):I think that should work, but there's a couple bugs in your example code. using UnityEngine; public class Example : MonoBehaviour { // Function to detect if a ray (representing a beam weapon, say) // makes contact with the collider's bounds.

However, if tmin < 0, I'm inside the bounding box, which means I don't need the entry point and I can just use the ray origin as my starting point.step(edge,A) returns 1 if A >= edge, 0 elsewise. Ray/AABB intersections are usually faster to calculate than exact ray/object intersections, and allow the construction of bounding volume hierarchies (BVHs) which reduce the number of objects that need to be considered for each ray. Thanks for that.I have a question about the surface normal. I care less about efficiency and more about avoiding false negatives.If you're not concerned with efficiency too much, just take the "naïve" code from part 2 and swap Can you please explain what is this 'double t' parameter is?It hurts me to say this but I believe that some of the functions do require comments about their input parameters. And actually for the test as written you can omit I'll try it out and see how much faster it is, thanks!What if I want to know the 't' of the intersection?Very useful! IOW, if the bounding boxes of two objects do not … Wait a second. By using our site, you acknowledge that you have read and understand our Stack Overflow works best with JavaScript enabled Is it box->origin - intersection ? Bounding box intersection is typically used for trivial-rejection of potential candidates. To find elements that are intersecting a geometry I am using the example post by Jeremy in his blog I am using another strategy that is acess the geometry of the instance to verify if the face of the family instace are clashing with a closer conduit.