Custom RayCast function

Hello!

The idea is to use Unitys Physics.Raycast with multiple cpu threads to speed things up.
But since Physics.Raycast is not thread safe i started to write my own raycast function.

Currently i cycle through all the triangles of a mesh and check if a ray intersects with the "Möller–Trumbore intersection algorithm".
But this is like 50 times slower than Unitys raycasting. Is there a better way to do this?
If my raycast would be 2-3 times slower than Unitys i would still be happy. Since i can still get a huge speed increase if i use 12 threads to process all the raycasts.

Or is a custom raycast function generally a really bad idea?^^

Thanks!

 

It would be a bad idea, since you can't count on anyone having 12 CPU cores. You don't get any speed increase by multithreading unless you actually have the hardware to take advantage of it. Most people only have 2 or 4 cores.

--Eric

 

Hi,

Actually a lot (if not most) of gaming pcs now have intel cpu with 4 cores and 8 threads considering hyper-threading, I also need parallel raycasts, any news on your progress Lizzard?

Thanks

 

to be honest it's only going to actually help when the raycasting is actually a bottleneck, given that the default is fairly efficient I'm thinking effort is best spent on other areas picked up by the Profiler and things like that...

 

if you are raycasting so much, that it is a bottleneck you might want to look into why you are doing so many casts, and what kind of better method you could use.

 

Time sliced raycasts are super effective for most of my work. But Unity probably needs to add support for threaded raycasting...

Depending on what you want to do, it's not total insanity. If it's not many meshes, you may want to build a small 3D table of nearby entry points or hash so you can skip most triangles, should be fast then... ie don't use mesh.