This console command changes the 'refractiveness' of your target (how transparent they are).
str [value] Target Command
|Value||A number, between 0 and 1 that specifies how 'refractive' your target should be. 0 would be invisible, 0.5 would be half visible, 1 would be completely opaque.|
This command would make your target completely visible.
The above console command would make your target invisible.
This is an alias of the SFH command (SetTargetRefraction is the exact same, just longer).