How expensive is line trace ?

[OptimisticMonkey]

@Raildex_;671725

No, this is not true. Line Traces should be used rare in one frame. They can slow down your system pretty easy. Never do 20 of them at the same time.

Sphere Overlaps are the easiest to compute Because the Radius is the only variable apart from the location to check.

A single Line Trace in one Frame is absolutely negligible, though.

Just wondering - have you done any performance analysis regarding this?

Both resolve to PhysX sdk scene queries against an internal culling structure.
In general, the queries are resolved in 3 steps (taken from Scene Queries — NVIDIA PhysX SDK 3.4.0 Documentation):

1. Broad phase traverses the global scene spatial partitioning structure to find the candidates for mid and narrow phases.
2. midphase traverses the triangle mesh and heightfield internal culling structures, to find a smaller subset of the triangles in a mesh reported by the broad phase.
3. Narrow phase performs exact intersection tests (ray test for raycast() queries, and exact sweep shape tests or overlap tests for sweep() and overlap() queries).

I was under the impression UE can support a relatively large number of queries every tick, and that both the overlap and the raycast are fairly equivalent in terms of performance, although I have not done any specific research yet.

Since a spatial partitioning structure is continually updated with all object positions, resolving scene queries may be very fast.

I am hoping to do a little more research and will post any findings.