Spell effects to target empty space

When i use the /fx macro, i have to use @[target|caster|token id] to make the effect start from the caster, but how can i make the target an empty space with no token? Couse if i use  @[target|enemy|token id], i have to chose a token, and the effect won't happen where i want, so i can't make spells like minor illusion's effect to happen in the unnocupied space i want, what do i do?

Based on what I have found you cannot without the ability to use the FX tool (I believe this requires a Pro account).  You could try using an invisible token that you could drag onto the map and let it be targetable by the players then just remove it after the FX has resolved

i'll do a bit of testing, if can´t find success with my account i'll visit a friend with premium later.

but to make that test i need to know wich is the macro for an empty space, since it isn't a token, "tokenid"won't work, so i want to know wich is the macro that correspond to an unocupied space, if someone knows, pleas tell me.  

Hi Ad J! There isn't such a command to my knowledge. You could plop down a temporary token for that purpose, otherwise you will need to use the manual drag method.

i see... that's sad, it would be more pratical to have a macro for the field, but since there isn't i'll have to come up with something like what you suggested.