Can Research techs contain constraints? (rebellion)

I believe the usage only applies to weapon type.  I've never seen anywhere in the vanilla game where you can limit a weapon upgrade to a ship simply based on code (unless it's the only ship of that weapon type).  I understand the program to seek out all assets that contain that particular type and applies the upgrade.

You're probable going to have to limit what ships have that particular weapon type.

Wait..  What?  Weapons can be used against any target unless limited by the bool for siege frigates.

The only way to make a weapon only affect one type of enemy would be to put a passive on that target ship and have the attacker not have a weapon but instead have an ability which would apply a buff to the target which would in turn check for the buff from the passive on the target and if found, apply a buff that would perform damage.

XATHOS is correct in that weapon types are used as the constraint in Research Subjects via the linkedWeaponClass keyword.

There's a few different options you could do.

1. You could use a weapon type not used on the faction to simulate what you want. This could include renaming an existing weapon class that isn't used in the game such as: ION, CAPITALABILITY, DART. You can't create new weapon classes though.
2. You could use an ability with up to 3 levels of improvements that only exists on that unit. The ability can increase damage, decrease cooldown, etc.
3. You could add an unlock-able weapon on the ship via the fireConstraintType. This weapon would come online only after the appropriate research subject is acquired.

I have a faction in which I have unlockable fighters with upgraded weapons damage, but it's unbalanced for the sins races. however, I'm trying to add that damage to the 3 sins races in such a way that the AI would actually benefit, since I have no way of knowing if it will use a new type of strike craft with upgraded damage over the base types. since I don't really want to go digging into any AI stuff at all, I figured a selective weapons tech would work best.

So considering I can't create a weapon type, I'll have to hope I haven't used them all already.

can fighters can get abilities ?(doubt it, but haven't checked yet)the main reason I don't just give the ship a researchable passive buff that applies a bonus for extra damage is I didn't consider the idea at all. I know you can get a buff for a ship that applies only to fighters, but i'm not going that route with vanilla races, too much change to their abilitysets for capitals and titans and starbases.

the most promising solution listed thus far sounds like the fire constraint. I can just add in an extra weapon for the missing damage, to be unlockable by research the same way a new ship type would be.

thanks for the help!

sorry, I didn't quite explain it all the way the first time. i'm trying for a research buff to weapons on one particular type of ship (in this case, fighters). i think zombie's solution will work, but additional ideas are always welcome.