Is Resilient Sphere opaque and soundproof?

Question

The fourth spell level wizard's spell Otiluke's Resilient Sphere describes the sphere as

A sphere of shimmering force

I always envisioned this to kind of look like "ball of force", a maybe shimmering, but basically transparent sphere made of force, similar to the fifth spell level spell Wall of Force (which explicitly states it is invisible), and we always played it like that. Most images picture it like that, too. We also used to play it so that you could still talk to the creature inside.

However, this question has answers that suggest the sphere might be opaque, much like Leomund's Tiny Hut from the outside. This would not only make a difference for gaze attacks, but more importantly, also for being able to purposefully move around in it and to observe the battlefield while protected within it. In addition, if nothing could pass, not even sound, then you also could not communicate with your team or anyone else.

So, is it opaque? Is it soundproof?

Answer 1

Up to the DM

The spell says:

A sphere of shimmering force

That's it. The rules don't say whether opaque or transparent. So the DM decides.

You can try to tie it in to other rules and build a logical structure that determines what the answer is, but the rules really just aren't that consistent.

So the DM decides.

Arguments for opacity

The spell says:

Nothing--not physical objects, energy, or other spell effects--can pass through

It's reasonable to assume that that means light and sound, they're energy, right? Basic physics. There you are in the sphere, and the only light or sound is from inside.

Counter-argument: "Physics"? Really? We broke physics back at the light cantrip. Earlier. Probably on page one of the Basic Rules.

Arguments for transparency

The spell says:

An enclosed creature can use its action to push against the sphere's walls and thus roll the sphere at up to half the creature's speed.

What's the point of being able to move it if you can't see where you're going?

Also, and it's a thin thread, I admit, part of the spell component says "clear crystal". Why say "clear" if the resulting sphere is opaque?

Counter-argument: Physics. It says energy can't go through. Light and sound are energy.

How to decide

Pick whichever feels most reasonable and go with it. You're not going to break the game either way. If you decide you don't like how it works, you can change your mind later.

Personally, I prefer transparent, because I think it seems more fun, and that's the way we've used it in games in the past.

In a game I currently play in, I have a wizard who has resilient sphere in their book, although I've never cast it. I've always assumed it would be transparent, because that's the way I've played it in the past, but I asked the DM. I got that DM look, and they said, "What? It doesn't say? Hmm. It's transparent, it's a hamster ball." So there you have it.

But it's your game, you decide.

As a player

If there's any doubt how it's going to work at your table, I recommend you ask your DM ahead of time, so that you can figure it out before you need to use it in session.

Answer 2

It is probably opaque

My first instinct was to use the description of the field, which is described as "shimmering". However there are several usages of this word in spell and item descriptions which do not appear to indicate an influence on opacity.

Take for example Shield of Faith and Dispel Evil and Good which both use an almost identical visual description but are obviously transparent.

On the flip side, Serpent Scale Armor is also described as shimmering however there's no indication that it is transparent. This is consistent with a dictionary definition of "shimmer" which only indicates the emission or distortion of light.

Hence, without a consistent pattern we have to fall back to a plain reading of the following text (emphasis mine) :

Nothing--not physical objects, energy, or other spell effects--can pass through the barrier

Sound and light are both energy, hence we can confidently say that neither of them can pass through the barrier.

Of course, the lack of specific mention to sound and light call into question whether this is intended, so your DM will need to provide a ruling.