Find intersection between two Line3

[Mike_Lee]

How can I find the intersecting point between two Line3s (if there is any)?

[Mugen87]

This is actually duplicate from here:

The Algorithm to Find the Point of Intersection of Two 3D Line Segment

You can compute the the shortest distance between two lines in 3D. If the distance is smaller than a certain threshold value, both lines intersect.

[hofk]

Did you see that?

[SOLVED] How to find intersection between two Rays?

http://discourse.threejs.hofk.de/2019/LinesDistance/LinesDistance.html from Collection of examples from discourse.threejs.org

[Mike_Lee]

Thanks for the link! I did not see this before.

[SOLVED] How to find intersection between two Rays?

Thanks @prisoner849 and @hofk !! The missing piece was to use the dot product (which I still have to get my head around) to get the result I was looking for. the method name could use a better name if anyone uses it. function isPositive( start, end, intersection ){ // all parameters are THREE.Vector3() let v1 = new THREE.Vector3().copy( end ).sub( start ); let v2 = new THREE.Vector3().copy( intersection ).sub( start ); return v1.dot( v2 ) >= 0; } // checks if two line segments will inte…

However, this seems to ignore the Z value. How can I retrieve the Z value for the intersection point as well?