I am going to use MDC by the book.
When I planned a rules post about MDC that was not what I intended to write. I was going to use a Monday Pointers to survey all kinds of MDC house rules. Then, on Thursday I was going to walk through several of these alternatives. Finally, I was going to discuss Jim Stoner’s alternative which I intended to use.
What changed? Three things changed my mind. Two things I found in my research and one classic OSR post combined to change my mind.
The first thing I discovered was MDC to SDC: taking out MDC on the Palladium Forums. Two points in the thread impressed me. While technically the second of the two points in reading the first to make a large impacts was so a LAW rocket which does 1d6*100 SDC will do 1d6 MD (pst by Nekira Sudacne). While at the time I thought it wasn’t true because SDC can never damage MDC I did find the damage amount interesting. With the MDC:SDC ratio set at 100:1 in theory you could house rule a 1d6*100 SDC weapon into an 1d6 MDC weapon. More importantly it gives some perspective on what MDC means both for armor and for magical creatures. In the movies we are okay with rifle fire never harming Godzilla but we expect an anti-tank rocket to get his attention. If we convert a LAW rocket to MDC (because SDC can never harm MDC) that works like we expect. Now, the hand-held MDC pistols are shrunken LAWs in terms of damage just as a LAW is a shrunken cannon. I can’t say KS used this logic back in the 80s to setup MDC but it’s reasonable.
Right before that line the post says in the rifts main book, it says that while a culmination of SDC attacks will never harm MDC (like a 9mm. handgun) a single massive SDC attack will. any explosion or attack that does 100 SDC will do 1 MD. the formula works in reverse. This I knew was not true. Oh, it’s a common house rule that is usually combined with dropping the MDC:SDC ratio to 20:1 or 10:1. However, the Rifts main book specifically says To damage a Mega-Damage Capacity (M.D.C.) structure you must use something that inflicts MegaDamage (M.D.) (pg 38) and Normal weapons do absolutely no damage to mega-structures (M.D.C.), even if the combined total damage is over 100 S.D.C (pg 40). That seems pretty clear-cut that SDC never does MDC. As I said, letting the LAW do 1d6 MDC was a common house rule and is possibly implied in the MDC example which calls a bazooka a mega-damage weapon.
However, what if Nekira Sudacne was referring to Rifts: Ultimate Edition which came out the same year as the thread? Yes, the dates are a little off but maybe some previews were released. In its MDC section it says Only S.D.C. weapons that inflict 100 or more S.D.C points of damage can hurt MDC armor. All other SDC attacks (1-99 points of damage) bounce off the armor like bullets bouncing off Superman. I’m not sure this was a clarification and we’d spent the 90s playing it incorrectly or Palladium had endorsed the house rule. Going back and reading Robotech where MDC was first introduced is no help as it could go either way although I’d still lean towards no SDC attack, even one that does 100+ points of SDC, do not affect MDC.
It is hard to underestimate the affects of allowing single 100+ point SDC attacks to do SDC/100 round down MDC. For one thing, conventional explosives now become useful on Rifts Earth. For that matter, boulders and gravity are now viable. When asked about what is the point of classes not arrayed with MDC weapons and armor in Rifts KS has long emphasized planning and stealth. When large-scale conventional attacks can work this makes more sense. Under the classic interpretation of MDC the two Ewok log pendulums would leave the Imperial walker undamaged. Now, the results could be straight out of The Empire Strikes Back.
Referencing KS’s discussion of how to use low powered classes in Rifts brings me to the third thing to change my mind. In one of the classics of the OSR Trollsmyth riffed on an earlier earlier James Maliszewski writing and argued we should analyze early editions of D&D through the idea that “D&D is always right”. The idea isn’t that the game is flawless but that the game does what it does for a reason. The reason may not even have been conscious and may have evolved in play but it does it for a reason. I decided to try “Rifts is always right.”
So, when the campaign starts we will use MDC as written. If the group doesn’t like how that works out we’ll experiment but for now we will play “Rifts is always right” at least when it comes to MDC.