In some other questions about holodecks here, and other episodes of Star Trek starting with The Next Generation, I've heard/seen that the holodeck can effectively create an infinite environment that allows real people and objects to (in simulation) travel far distances from each other while still interacting with the same program.

However, in "Encounter at Farpoint" it is demonstrated that (at least, some) simulations do indeed have finite bounds. This is shown when Data throws a rock at what he identifies as the rear wall.

How is this reconciled with the rest of Star Trek canon, relating to simulated environments in the holodeck? Or, is it just an unresolved inconsistency?

1 Answer 1


It's never been completely consistent, but the general idea is that the Holodeck tricks the people inside it, so they don't realize they're still in a small room.

To quote the relevant part of Memory Alpha's page on Holodecks:

Holodeck walls can generate holographic images that appear to extend for an unlimited distance, seemingly much larger than its own dimensions. In doing so, however, the holodeck is aware only of its users; it does not recognize its own created objects. For example, if a person were to throw a holographic rock at the holodeck's walls, the rock would not be allowed to pass beyond the wall (if it were of replicated matter). (TNG: "Encounter at Farpoint") It does this by continuously adjusting the projections of the force fields and the use of a force field "treadmill". With this, an individual approaching a wall causes an instant shift away. It can also manipulate light photons, 'lensing' them to make individuals appear further away if two persons were separated in a scenario. The holodeck can change gravity in three dimensions, so occupants don't notice the change, (Star Trek: The Next Generation Interactive Technical Manual) as observed during the stop of B'Elanna Torres' holographic orbital skydiving session. (VOY: "Extreme Risk")

Additionally, it's shown that in some cases these tricks aren't foolproof, as in VOY 4x18-4x19, The Killing Game and The Killing Game, Part II, when the walls between Holodecks were broken down to make one huge hunting arena.

  • Canonical or not, this seems illogical. Why break the illusion just because a holographic rock is thrown at the back wall, when walking toward the back wall yourself would lead to effectively walking "through" it?
    – Iszi
    Commented Mar 26, 2012 at 1:43
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    @Iszi I read it as a limitation on the technology's capabilities. Other sources also bring up that simple objects - for example: water, snow (also seen in Encounter at Farpoint), and paper - are more likely to be replicated than simulated, because it would take more power to simulate their reactions than it would to simply create the substance. If the rock in Encounter at Farpoint was replicated instead of simulated, then it would make sense - it's flying through the air, the holodeck doesn't really have anything to "treadmill" it with.
    – Izkata
    Commented Mar 26, 2012 at 1:49
  • So, are you suggesting that a human leaping or being thrown by some means towards a wall would have the same problem?
    – Iszi
    Commented Mar 26, 2012 at 6:45
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    @Iszi I should also point out that, AFAIK, the "simple objects are replicated" explanation is an extremely common theory based on how often simple objects do leave the holodeck, how complex ones can't, and how holodecks are related to replicators/transporters. I think the first part of the quote in my answer is it for official canon (the TV series).
    – Izkata
    Commented Mar 26, 2012 at 11:45
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    The treadmill part is the most relevant. We could argue that more advanced holodecks could (at some point in its trajectory) dematerialize the rock and replace it with a believable projection, thus fooling people inside. Also, holodecks do have limits on the treadmill effect. So larger holodecks are better than small ones (try fitting lots of people in a small holodeck). Commented Mar 27, 2012 at 0:52

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