5 kinds of character damage track:
Hit Points: usually, GM option to do lasting injuries when any marked, dead when all gone.
Personal SDC (pSDC): a second kind of damage track, no effects until depleted, then all further damage is to HP. Not present in some early versions
Armor SDC: Damage track for worn armor. When depleted, remainder passes on to pSDC.
pMDC: personal megadamage capacity; hit points for many MegaDamage critters are pMDC.
aMDC: megadamage capacity of armor. All MegaDamage armor is always effective. When depleted, passes to pMDC
Vehicles have
Structural SDC - same as pSDC for characters, but when gone, breaks
Armor SDC - as characters, but feeds to sSDC
structural MDC - equivalent to pMDC
Armor MDC - same as characters.
2 kinds of damage:
SDC/HP Damage: SDC and HP are the same kind of damage, and it's 1:1 between. Cannot do damage to any non-Zentraidi MDC structure; Zentraedi actually have HP in the hundreds, not pMDC.
MDC damage: 1:1 for MDC, ×100 conversion to SDC tracks
Combat is 1d20+Skill Mod, needing 5+ to hit. If standard damage weapon and standard armor, rolls 5⋯ ArmorRating-1 hit the armor SDC, AR & up hit the personal SDC.
MegaDamag Armor is always hit on 5+.
Nat 20 and sometems lower, can do various special effects.
Initiative is usually rolled, but is vague in many. 1d20 plus any listed mods from combat skills
Work downward until everyone's done one action. Repeat the count if there are attacks left...
Note that reactions (parry, dodge, roll-with-impact) cost an attack, and must roll higher than the to-hit to be effective.
Note that Robotech mecha combat attacks also get the character's personal attacks as well, so rounds can get up to 6+ attacks per melee round.
All combat skills are tables, giving a modifier to hit, and some other effects.
Non combat skills are percentile, 1d100 ≤ skill + mods to succeed.
There are no interpersonal skills, nor rules for influencing others. Siembieda is vehemently opposed to them... screed in most corebooks.