[Solution] Untiy3D, the ray is blocked after Canvas adds a background image

Problem Description:

        There is an object in the scene that needs to be selected, and the function has been realized. Due to the UI problem, it is necessary to add a background image to the Canvas, which causes the selection effect to fail because the rays are blocked.

solve:

     Uncheck Raycast Target by default. 

Solution via:

        Thanks to the friends of the siki group.