Ok here are the basic…
suppose we have a camera and some object like a cube:
You want to linetrace from the camera towards its viewing direction and evaluate if it hits some object. You must do this for the linetrace:
this is the results:
you can see that is hitting because at the end there is a red rectangle.
in the blueprint:
IMPORTANT: Note trace channel is set to visibility:
the box is set to default:
but you can cherry pick what do you want to be used in the tracing if you select custom…all set to block will generate hits in their channel:
you can also make a custom Trace Channel in settings like this:
but remember to set that channel in your objects as BLOCK and also in the bleuprint node:
Hope it helps
Cheers!
Dany