A naive raycast problem solution for people who are tired enough.

*Notice. it may not fit with you're case. i'm not a unity guy who has responsible for write right code for everyone. but you could get a idea from my solution. And sorry about my poor grammar, I'm not a native.

First of all, I'm tired with waiting a patch to solve this. This raycaster problem is existed since the first version of unity 5 until now. And It was too painful to hard-code workarounds case-by-case. So i finally open the ugui project which is open project at bitbucket. I changed just a line of code, and it worked nicely.

0. I used 5.2.0 version for this solution. go get a project at here
https://bitbucket.org/Unity-Technologies/ui/downloads

1. GraphicRaycaster.cs Line 181.

Code (csharp):

1.  
2. sortingLayer =  canvas.cachedSortingLayerValue,
3.  

Change this code to

Code (csharp):

1.  
2. sortingLayer =  canvas.sortingLayerID,
3.  

this.

And you're done. Just build dlls and put its in a installation folder as instructed here.
A line of code change will resolve most of raycaster issue.
https://bitbucket.org/Unity-Technologies/ui/overview

ps1. in my view, the evil of root for this problem is EventSystem.RaycastComparer() and Raycasters. if you face another raycast problems, take a look those classes.
ps2. if you're facing a compile problem at editor when you try to bulid, restart your editor it'd resolve many issues.

 

thanks for your info. and please make a good patch note next time since i couldn't find any note about it.

 

Which issue exactly is this about? I'm in 5.2.1.f1 and still having issues with raycasters when used with world-space canvases and perspective cameras. I submitted a bug report with code to fix the issue (raycasters using Raycast instead of GetRayIntersection) a few weeks ago, but it was never turned into an Issue.

 

it's about when you use multi canvases with multi sorting layers.