HTMLHumankind has long been fascinated with the idea of parallel dimensions, the theory being that alongside our own universe lie virtually identical universes in which people just like us live out their lives (and perhaps fantasise about parallel dimensions). The popular notion is that in a parallel dimension, some different decision was made, some random event occurred differently, or that some element in the composition of the Earth is more common and, as a result, the universe is different to some degree or another. What if Wellington lost the Battle of Waterloo? What if the cataclysm that wiped out the dinosaurs never happened? What if Hitler conquered the world?
Of course, it could all be considerably more subtle than all that; perhaps all humans have gray eyes, and that's the only difference. The point is that in alternate realities, life could be different. Without ever leaving their home world, dimensional explorers could face challenges every bit as daunting as the challenges faced by space explorers.
Any initial exploration of parallel dimensions must logically proceed from a fixed location, because the amount of energy required would not allow for a portable power source. Thus, as with interstellar travel, early interdimensional trips are likely to be one-way. Fortunately, if a beachhead can be established in another dimension, it should be a simple matter for subsequent expeditions to transport the materials necessary for the construction of another power source.
It is in establishing that beachhead that the real risk lies.
Initial dimensional journeys are unlikely to be carried out by humans, but rather by probes designed to test the gravity, radiation levels, atmosphere, pressure, and temperature and to bring back samples of microorganisms to ensure that humans can survive, and that they are properly equipped. Such probes must be tethered to the original dimension to send back information (since there is no indication that communication signals would travel back any more easily than objects could).
The use of probes, however, should allow dimensional physicists to develop a kind of "matrix map." Not only can they note which dimensions are hostile to human life, but, with sufficient data points, they can extrapolate which dimension "frequencies" are likely to prove conducive to human life. The first human dimensional travellers are likely to be extremely well prepared for the environmental conditions they encounter.
Other factors may prove more hazardous, however. In addition to the perils of first contact with a xenophobic populace, dimension travellers must contend with the possibility of equipment failure, dimensional static, scale variance, and encounters with other travellers who might not be friendly.
As the science of dimensional travel advances, explorers carry portable dimension gate generators, enabling them to come and go through dimensions as they please. If that equipment fails for some reason, the expedition might be trapped, possibly without the means to repair the damaged generator.
Dimension gate generators whether stationary or portable should not break down at random any more than a starship does (unless, of course, the campaign revolves around that very problem).
Complete Shutdown: The generator simply stops working, either because its components are damaged or because it has run out of power. Fixing damage components usually requires 10 hours and a successful Repair check (DC 25), while constructing a new power source (a complex device) requires 60 hours and a successful Craft (electronic) check (DC 25). Locating a replacement power source in a civilised area may require a successful Gather Information check, and negotiating for it may require a Diplomacy check.
Miscalibration: A miscalibrated dimension gate generator doesn't take the characters where they planned to go. Correctly recalibrating the generator involves either downloading the data from another functional generator (a full-round action followed by a successful DC 10 Computer Use check) or returning to the last "accurate coordinates" and resetting the matrix (12 hours of work followed by a successful DC 25 Computer Use check).
Communication Failure: There is no guarantee that standard communications work across dimensions; even communications designed to work across interstellar distances are useless when the party for whom the message is intended is not in the same dimension. A d-com (see Dimensional Communicators, below) or similar device enables communication across dimensions.
Dimensions are constantly splitting into new dimensions as events create alternate realities. These divergences release tremendous amounts of energy, which manifests as a kind of "static" during dimension gate operations. Generators are designed to filter out this noise and lock onto the specific "signal" of the intended destination.
However, if the generator isn't getting enough power, or if the static level is extremely high, the gateway between dimensions is less stable.
Travelling through an unstable gate is potentially fatal. The traveller must make a Fortitude save (DC 15). If the check succeeds, the character arrives at the intended destination but is stunned for 1d4 rounds. If the check fails, the character arrives on target but is nauseated for 1d4 hours. If the save fails by 5 or more, the character arrives on target, takes 2d6 points of Constitution damage, and is nauseated for 1d4 hours.
A potential risk in travelling to other dimensions is a matter of size: Is everything in the other dimension on the same scale as the travellers who visit it? A scale variance can be simulated by changing a character's effective size.
For example, a Medium-size character might be considered Fine in the new dimension. Such a variance, of course, changes the character's size modifier to attack rolls and Defence. Speed also changes, multiplied by a factor based on the change in size: Fine ×0.16, Diminutive ×0.33, Tiny ×0.5, Small ×0.66, Medium-size ×1, Large ×1.33, Huge ×2, Gargantuan ×2.66, Colossal ×3.33.
The damage a character deals with natural and artificial weapons also scales with size. For every step by which a character's size category increases or decreases, increase or decrease the damage by one step: 1, 1d2, 1d3, 1d4, 1d6, 1d8, 2d6, 3d6, 4d6, 6d6, 8d6, 12d6. Attacks that deal 2d4 points of damage scale down to 1d6 or up to 2d6. Attacks that deal 1d10 points of damage scale down to 1d8 and up to 2d6. Attacks that deal 1d12 points of damage scale down to 1d8 and up to 3d6.
If humans are capable of travelling through dimensions, it is reasonable to believe that intelligent beings, either from other worlds or other dimensions, also have this capability. Other dimensional travellers might not be friendly. They might be raiders, plundering other dimensions for the resources they lack in their own. They could just as easily be transdimensional traffic police, tasked with detecting and disabling unauthorised dimension gate generators. They could simply be savage monsters, naturally capable of dimensional travel and drawn to unusual interdimensional activity.
The technology behind dimension gates is highly advanced. The first working gates are treated as late Progress Level 7 technology, and concerted human exploration of alternative dimensions begins at Progress Level 8. The calculations required for dimensional travel are complex, but the calculations for safe travel arriving at the intended destination with no loss of carrier signal are tens of thousands of times more complex.
Actually travelling through a dimension gate is easy, but changing the setting is more complex. A character must succeed on a Navigate check (DC 30) to reset the gate to a known destination; setting the gate to an unknown (but safe) destination is a DC 40 Navigate check. (These checks should be rolled secretly.) Performing either check requires 30 minutes of calibration. Of course, if the destinations have been preset, any character can change the settings as a move action without making a check.
Dimension gate generators come in a variety of forms, each operating somewhat differently.
D-Gate Generators (PL 7-9)
The first dimension gate generators appearing at Progress Level 7 are Gargantuan objects that cannot be transported once assembled. The PL 7 D-gate creates a transdimensional aperture approximately 10 feet in diameter and allows for one-way transport only. Due to the incredible power drain, the gate remains open for only 1 round, after which the generator shuts down and cannot be activated again for 24 hours.
The PL 8 D-gate is a Huge object weighing 200 pounds, but due to its bulk, the generator requires at least two people to lift and haul it. It creates a transdimensional aperture up to 20 feet in diameter, and the generator can keep the gate open for up to 10 rounds, after which the generator shuts down and cannot be activated again for 24 hours. Dimensional mapping makes calculations to reset the gate's destination easier (Navigate check, DC 25), and any given gate can store up to five predetermined destinations. Travel is still one-way, but with the larger aperture and the destination presets, the equipment to construct another D-gate can be transported through, and the travellers' home dimension can be locked into the new gate upon startup.
At PL 9, D-gates large enough to transport starships exist (although they can be almost any size), and they can store up to twenty predetermined destinations. The calculations are even easier (Navigate check, DC 20), and scientists have finally learnt how to keep the gate open indefinitely. Best of all, dimensional travel through PL 9 D-gates is two-way, allowing for round trips.
Purchase DC: 54 (PL 7 D-gate generator), 48 (PL 8 D-gate generator),
46 (PL 9 D-gate generator).
Restriction: Military (+3).
D-Drive Generator (PL 8-9)
The D-drive generator can be incorporated into a starship's engine design, allowing the ship to travel between dimensions. Considered the safest form of dimensional travel, D-drive generators allow ships in space to cross dimensions. Due to the enormous power drain, the D-drive generator shuts down for 12 hours after the dimensional jump is completed. In addition, the starship's weapon systems, defence fields, defence screens, and engines shut down for 2 hours. At Progress Level 8, only Colossal starships can be fitted with a D-drive generator. Progress Level 9 sees many improvements in the D-drive generator.
Any size starship can be equipped with one, and the generator can be reactivated after 6 hours; the ship's disabled weapons, defence fields, defence screens, and engines come back online after only 10 minutes.
Purchase DC: 48 (PL 8 D-drive generator), 44 (PL 9 D-drive generator).
Restriction: Military (+3).
Dimension Wand (PL 8-9)
The dimension wand is a personal dimension gate generator. It creates a rupture in the fabric of reality just large enough for one character to step through into another dimension. The gate remains open until the wand itself passes through, so multiple characters can step through without using their own wands. The drawback to the dimension wand is that it must be re-calibrated after each use (see Equipment Failure, above), or entirely new dimensional coordinates must be entered, as though changing the settings. The PL 8 version of the dimension wand weighs only 1 pound. The PL 9 version has the same purchase DC, with the added benefit that it stores the last five dimensional coordinates automatically, enabling anyone to thumb through settings without recalibrating the wand.
Weight: 1 lb.
Purchase DC: 42.
Restriction: Restricted (+2).
In addition to dimension generators, most dimensional travellers at Progress Level 8 and beyond carry dimensional transceivers.
Dimensional Transceiver (PL 8)
A dimensional transceiver permits two-way communication across dimensions, although dimensional static can sometimes hinder or block communications. The somewhat bulky PL 8 transceiver can be carried like a backpack; a handheld version is available at PL 9.
A dimensional transceiver must be calibrated to transmit signals to a given dimension. Assuming the coordinates have already been plotted using some kind of dimension generator (see above), calibrating the transceiver takes a full-round action and requires a successful Computer Use check (DC 15), The PL 9 version can store the coordinates of up to five different dimensions.
Size: Medium (PL 8), Tiny (PL 9).
Weight: 4 lb. (PL 8), 1 lb. (PL 9)
Purchase DC: 24.
Restriction: Restricted (+2).
