There is an axis that spans the spectrum of magic and technology and every person, every item, every arcane energy falls somewhere on that axis. Most are near the center, and have no impact on other energies or activities, but some of these actors are polarized enough to affect the world.
Character Creation and Advancement
There are two Arcane Backgrounds (only) in the Savage Arcanum world: Magic, and Tech. Magic works like any magic AB. Tech works like Weird Science (that's a working hypothesis; adjustments for balance may be required once the full rules are available). The two skills are called Spellcasting and Technomancy. Characters are permitted to take one, both, or neither of the AB's.
Both Spellcasting and Technomancy increase as if they were in excess of their linked attribute. This applies at creation as well as advancement.
Additional edges are recommended to help differentiate Magic and Tech.
Calculating Axis Ratings
Each character has a rating on the axis of magic and technology dependent on how powerful they are with each of the arcane energies. Each character takes 1/2 of the die type of the appropriate skill to determine what their rating is. A character with Spellcasting d6 would have a Magic 3 rating. A character with Technomancy d10 would have a Tech 5 rating. When a character has both AB's, she calculates each rating normally, then subtracts the smaller from the larger. If both skills are equivalent, then the character is balanced and at 0, meaning she does not influence the flow of energies through the world at all. As a final example, a character with Technomancy d12 and Spellcasting d6 would have a rating of Tech 3.
Certain, very powerful items will also have ratings. These will generally be in the range of 1 or 2. They simply add (or subtract from) the rating of the character carrying them.
Some locations are polarized, as well, and carry a rating. These will typically be from 1 to 5. The effects of this are detailed in the next section. For example, a graveyard might have a rating of Magic 3. A tech city might have a rating of Tech 4.
Interference
Magic and Tech, being opposites, interfere with each other. There are two ways this happens. First, each character with a rating causes any oppositely-aligned skill or device use within a Medium Boom template to take a penalty in the amount of the rating to any rolls made within that zone. In other words, a mage with Magic 3 would cause another character to take a -3 to any Technomancy rolls made within the range of a Medium Boom template of the mage.
Note that this means a dual-AB character will be causing penalties to her own skill rolls if she is not in balance. Given the restrictions on advancement for the skills in question, it is likely that a dual-AB character will experience this at least part of the time.
The only devices that are affected by interference are those that have an algnment already (in other words, are very powerful) or other devices specifically designated as Magic or Tech devices. Any item made using the Spellcasting or Technomancy skills are automatically considered aligned, though they have no rating of their own. Interference causes a negative modifier in the amount of the oppositely-aligned rating to the use and damage (or effect) of any device.
Multiple fields from multiple characters stack to create a highly-dampened area.
Locations subtract the strength of their rating to all oppositely-aligned skill and damage rolls within their influence. In addition, strongly aligned areas (those with a rating of 3 or more) expand and shrink the templates that are used to determine a character's area influenced. Similarly-aligned characters expand their range to a Large Boom template. Differently-aligned characters see their area shrink to that of a Small Boom template.
For example, a Magic character (of any strength) in a tech city (Tech 5) would subtract 5 from any Spellcasting rolls and from the damage (or effect roll) of any Power used in that city. In addition, that mage would see her zone of influence to shrink to a Small Boom template.
The second effect of interference occurs whenever a Power or aligned-device targets an oppositely-aligned character. In that case, the effect and damage rolls (only) are reduced by the target's rating, just as if they were activated within the zone of influence. The roll to activate or target the power, however, would not be affected in this case.
Synergy
Locations also add their rating to any activities within their area that are similarly-aligned. This means for all activation, effect, and damage rolls.
Examples
Margo the Magician (Spellcasting d10, Magic 5) with a magic shield (Toughness+3, Magic 1) is going to fight Terrance the Techie (Technomancy d8, Tech 4) and his Bomb Thrower (Blast Power, Tech 0).
Explanation: Margo is listed with Magic 5 because that is half of her Spellcasting die type. The shield is magically-aligned, and has an interference value, since it is a fairly powerful item. Margo's total rating is Magic 6. Terrance has a Tech 4 rating due to his Technomancy skill and it's worth noting that his powers will always have a tech alignment to them.
The characters stand far enough apart to be out of each other's Medium Boom templates. They draw cards, and Terrance goes first. He fires his Bomb Thrower with a roll of a 7 -- good enough to hit! The bomb is a standard Blast, so does 2d6 damage. Terrance rolls and gets a 14, but the damage is reduced by 6 due to Margo's Magic 6 rating. The resulting 8 is barely enough to leave Margo Shaken, but unhurt. On her action, Margo recovers.
In round 2, Margo draws the better card and she fires a 3d6 Bolt at Terrance! Her attack roll is 5, which is also a hit, and she rolls for damage. She gets a measly 8, which is then reduced by Terrance's Tech 4 rating to only 4. Terrance is still going strong. He fires again. . . .
It won't take long to figure out that oppositely-aligned characters will have a difficult time hurting each other. A mage duel on a magical hilltop, however, will be fast and deadly, deadly, deadly. Also, consider how Terrance would do in a Tech 2 location, since he would add 2 to each attack and damage roll, and Margo would subtract 2 from each attack and an additional 2 (she's already subtracting 4 for Terrance's rating) from each damage roll. Pick your terrain wisely in the world of Savage Arcanum.