Hello all,
I'm trying to simulate radio communication in FlexSim.
I need to detect whether there is an obstacle between objects.
Specifically, I want to detect whether there is an object that overlaps the line connecting the centers of the wireless terminal objects. The CAD shape of the object can be ignored and assumed to be rectangular a cuboid.
What would be the best way to do this?
Thank you.
The line goes through the coboid if it intersects with any of its faces. Each face defines a plane in 3D space. The intersection point of the line with that plane (if not parallel) can be calculated relatively easily. You then have to check whether that point is part of the surface.
The math is summarized pretty well under the following link:
https://www.wikiwand.com/en/Line%E2%80%93plane_intersection
If you take the vectors that define the plane to be equal to the edges of the object (vectors between corner points) then the line intersects the face if 0 <= u <= 1 and 0 <= v <= 1, as mentioned on the linked page.
pnm is the vector between the points pm and pn, same goes for lab.
In the Flexsim the Vec3 Class offers all necessary methods for these calculations. The 'getLocation()' method can be used to get the corner points of the object, serving as p0, p1 and p2.
Thank you for your response.
I understood the mathematical theory.
So, should I use this decision method to all objects that can intersect the radio communication path?
Depends on how many objects there are. In general, I would recommend to first to a rough check (distance from object center to line) to see if an intersection is possible. Only then do the check above to improve performance.
The distance can be gotten quite easily:
|pxp0| = |p1p0| * sin(α), where p1 and p2 define the line and p0 ist the objects center
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