For a ray sensor, I want it to detect object without a specified prop. I will put it as invert. If I use invert with x-ray mode, it will invert the x-ray mode. How can I use x-ray mode to detect an object without a prop?
You can do that by a logic operation and two ray sensors :
1- the first ray sensor detects objects with prop
2- the second ray sensor detects any objects
the objects you want to detect are any object except the ones that have prop so use the expression :
Ray_2 and Not Ray_1