One of my readers asked me a question about how I use the Hirst Arts blocks in play and whether my use of them interrupts the flow of a session. I thought it an interesting enough question that I'd make a post about it.
To really answer this properly, you have to understand how I run a game session. I'm not what you'd call a deeply "immersive" referee. I am big on describing things, sometimes at great length, but I don't do it in a way intended to "transport" the players into the game world. I address them as if they were their characters -- using "you" rather than "your character," for example -- but there's an implicit understanding that this is an artifice. I've never been a huge proponent of the "theater of the mind" approach to refereeing. I prefer to maintain a distance between myself the game world and it's a distance my players maintain as well.
No doubt this will disappoint some people, but there it is. My players and I freely "break character" and shift back and forth between the game world and the real one, in order to kibitz, ask and answer questions, and just socialize. I'm not a referee who demands the full attention of my players and they often are perusing books, jotting stuff down in notebooks, and so forth while I'm holding forth at the head of the table. That's pretty much how I've always played and I'm comfortable with it. Amateur thespianism is a rare occurrence in my groups and, when it does occur, it's more a matter of whim than planning beforehand. In short, we never forget we're playing a game, even when I'm portraying some NPC giving an impassioned speech to the PCs.
So, when the characters are exploring Dwimmermount, I'll roughly describe what they see, using vague terms first -- "It's a cave approximately 30 feet wide and 50 feet deep with a passageway heading off to the northwest and another one heading to the south." -- and then providing more specific details as the characters enter the room and start poking around inside of it. Dordagdonar's player is mapping this out on graph paper and I'll give him more accurate information for his map once the PCs have taken the time to fully explore an area. Concurrently, we're often using our Hirst Arts blocks to create a rough-and-ready representation of the area. Note that I said "representation." We have a lot of blocks at our disposal but not enough to show every possible room/cave/area with 100% accuracy. Sometimes -- often -- we just have to make do with "good enough."
When this mapping and block building is happening, we're generally not "in character" except in the sense that I try to describe things as the characters would see them. That means leaving out details or elements that they haven't looked for or wouldn't notice without special effort. But the mapping and building are both activities in which the players are involved rather than their characters, if you understand what I mean. I have never worried about maintaining a "mood" or "atmosphere" while playing; that sort of thing either happens or it doesn't in my experience and assembling a dungeon room from plaster blocks no more breaks it than does rolling dice or ticking off damage on a character sheet does. Or rather, it can break the mood but it doesn't have to. As I said, I don't aim to manufacture mental states in my players through dialog or description. Sometimes it happens anyway and sometimes it doesn't but I have comparatively little ability to achieve either end by design.
I don't mean to repeat myself but I'll say again that my group never loses site that we're playing a game, so putting together a dungeon doesn't disrupt "the flow" any more than any other aspects of the game rules. We keep ourselves at a certain distance from what's going on in the game, simultaneously being observers outside the events of the session even as we're also participating in those events from the inside. This is the most natural way to play for me. I can't really imagine immersing myself so much in the game world that I feel like I'm really there. Neither can I look down on everything like a game board and treating the characters as mere pawns to be pushed around. This is a middle ground between the two approaches and it's the one that, in my limited experience, makes the game most accessible to newcomers who might otherwise worry about "doing it right" without reducing it to a level of abstraction that bleeds away any personal investment in what's going on.
I hope that made sense.