Nasty trap... does it work accd to RAW?

[Herobizkit]

In one adventure I played in, I had devised a terrible way for trolls to die.

I was in a four-way passageway. East and West passages ended in dead ends, North and South open.

Halls are 5' wide, center passageway 10' wide

I had created a wall of force opposite me, followed by another closer to me. This blocked off the only exits from the centre passageway. I then created a wall of fire in the center passageway, completely filling it. The trolls had nowhere to run.

The question I have is this:
Does this 'trap' function if I create the walls of force before dropping the wall of fire? I know the spell description of wall of force says thats spells cannot pass through it, but I am conjuring an effect behind it. My DM allowed it, but I'm curious if other DMs would have as well.

 

[Jack Simth]

You need line of effect to where you create the fire, and a wall of force blocks line of effect. Granted, it's a cool effect (wait... that doesn't sound quite right...) but as far as I'm aware, it doesn't work by raw. You need to place the wall of fire before you add the closer wall of force.

 

[Starglim]

What Jack said. The spell that you want is forcecage - all spells can pass through the barred cage version, but trolls can't.

 

[HeavyG]

The trolls could also have squeezed into the 5' wide side passages, if I understand the situation.

 

[dcollins]

I know the spell description of wall of force says thats spells cannot pass through it, but I am conjuring an effect behind it.

No, that's exactly what "casting spells though it" means. You should read the rules for "line of effect" in the PHB Magic chapter.

 

[Herobizkit]

Thanks for the input. I had a feeling that 'no' was the answer. The trap still would have worked if I had went wall-fire-wall, and I had the means and the time to do so.