EternalTD Towers

EternalTD has one damage tower, one wall tower, and a family of support towers that modify whatever Basic Tower they sit next to. Every tower in a player's hotbar/inventory is generated from the current source code, so the numbers below match what shows up in the in-game item lore.

Tower Costs and Display Materials

Tower	Base cost (gold)	Item material	Entity used as tower body	Elemental attunement
Basic Tower	10	ARROW	SKELETON	Unattuned
Barricade	3	OAK_FENCE	IRON_GOLEM	Unattuned
Sugar Tower	20	SUGAR	SHEEP	Air
Spyglass Tower	20	SPYGLASS	PHANTOM	Unattuned
Beam Generator	40	BEACON	GUARDIAN	Air
Explosion Factory	40	TNT	CREEPER	Earth
Ice Box	40	SNOWBALL	POLAR_BEAR	Water
Armor Crusher	40	SHIELD	PIGLIN_BRUTE	Earth
Obsidian Quarry	20	OBSIDIAN	ENDERMAN	Earth
Gold Mine	100	GOLD_ORE	VILLAGER	Unattuned
Napalm Dispenser	40	BLAZE_POWDER	BLAZE	Fire

Tower Pricing Scaling

Tower costs start at the base price and stay there for the first 15 towers in a session. After that the code adds a flat surcharge to the displayed price:

cost + (int) (1.2 * floor(totalTowersInSession / 10))

The result is truncated to a whole number, and the surcharge only applies at all once the session holds 15 or more towers. Because the multiplier is 1.2 rather than 1, truncation makes the step size uneven — it is not a flat +1 per ten towers:

Towers in session	Surcharge
0-14	+0 (gated out entirely)
15-19	+1
20-29	+2
30-39	+3
40-49	+4
50-59	+6
60-69	+7
70-79	+8

Every time the tower count crosses a multiple of 15, the session tells the player the new surcharge.

The upgrade cost is 4 × the tower's stored cost — the stored cost is the base price, not the surcharged one, and it is itself multiplied by 4 on each upgrade. Selling a tower returns 75% of its current cost (surcharge included), or the full purchase price if you sell within 5 seconds of placing it.

Basic Tower

The only tower that actually deals damage.

• Base damage: 1
• Base range: 10 blocks
• Base attack speed: 2 seconds per shot (the configured value, and what the item lore shows)
• Upgrade doubles the tower's damage on each level and changes its armor tier (leather to iron to gold to diamond to netherite).
• Shoots arrows by default. Behavior changes when paired with support towers.

The projectile is not a real arrow entity: it is an ItemDisplay holding an arrow item, steered tick-by-tick toward the target, and damage is applied manually once it comes within range. Real arrows are unreliable against the invulnerable, AI-disabled skeletons that make up tower bodies on current server builds.

Real firing cadence

The tower's scan loop only fires once its internal counter reaches twice the computed attack interval, so the real cadence is twice the configured value — 4 seconds per shot at base, not 2. The same doubling applies to the beam transformation, whose 5-tick interval fires every 10 ticks; that is exactly what its 0.5s base attack speed display line reports. Support-tower attack-speed bonuses scale this cadence, they do not remove the doubling.

Barricade

A pure wall tower.

• Cannot be upgraded.
• Cannot block enemies if it leaves no path to the end (pathfinding check happens on placement).
• Provides no combat bonus.

Support Towers

Support towers do not shoot. They modify a Basic Tower in any of the 8 squares adjacent to them. Effects from multiple support towers stack on the same Basic Tower.

Sugar Tower (Attack speed)

• Baseline attack-speed bonus: +10% per Sugar Tower placed next to a Basic Tower.
• Each upgrade adds another +10%.

Spyglass Tower (Range)

• Baseline range bonus: +1.5 blocks.
• Each upgrade adds another +1.5 blocks.

Beam Generator (Transformation: Beam tower)

• Adds a "beam generator count" to the Basic Tower.
• Transforms attack into a beam:
  • 0.5 second base attack speed instead of 2 seconds.
  • Base damage drops to 1/8 of the tower's damage.
  • After a 3-second charge against the same target, the beam reaches its maximum damage multiplier (3×).
• Upgrades add more beam generators, which shorten the warmup time (60 − 3 × (beamGenerators − 1) ticks).
• The beam is purely visual particles, no entity projectiles.

Explosion Factory (Transformation: AOE)

• Baseline AOE radius: 2.0 blocks.
• Each upgrade adds 0.5 blocks of AOE radius.
• Direct-hit damage is not applied to the primary target; instead, every wave entity within the AOE radius takes the tower's processed AOE damage (1/4 of base).
• Other support effects (slow, fire DOT, etc.) propagate through the AOE damage call.

Ice Box (Slow)

• Baseline slow on hit: 5% movement speed reduction.
• Each upgrade adds another 5%.
• Slow lasts 5 seconds per hit.
• resist wave entities ignore slow effects entirely.

Armor Crusher

• Baseline armor damage: 20% of the tower's damage.
• Each upgrade adds 10% more.
• Total armor-damage share is capped at 100%.
• Wave entities at wave 10 and above gain armor (maxHealth / 80), which subtracts from incoming damage until shredded. Armor Crusher chips that armor down faster.

Obsidian Quarry (Critical hits)

• Baseline crit chance: 5%.
• Each upgrade adds another 5%.
• Crits multiply damage by 1.5×.
• Total crit chance is capped at 100%.

Gold Mine (Bounty)

• Baseline currency bonus: +10% on kills made by the attached tower.
• Each upgrade adds another 10%.

Napalm Dispenser (Fire DOT)

• Baseline fire-DOT share: 10% of the tower's damage is dealt as fire damage over time.
• Each upgrade adds another 10%.
• Fire DOT bypasses armor and applies as 3 ticks over 9 seconds.
• The DOT amount is removed from the direct hit damage so total damage stays balanced.
• Total fire-DOT share is capped at 100%.

Tower Upgrade Visuals

Tower armor stand equipment changes with each upgrade level:

• Level 2 — leather armor
• Level 3 — iron armor
• Level 4 — gold armor
• Level 5 — diamond armor
• Level 6 — netherite armor

When FreeMinecraftModels is installed, the model also swaps between named variants per level (stone, gold, diamond, emerald, netherite, redstone).

Bonus Display Tags

Every placed Basic Tower gets a stack of invisible armor stands above it showing its live effective stats. Damage and Attack Speed are always present; the remaining lines only appear once a support tower actually contributes that bonus:

• Damage, Attack Speed (unconditional)
• [Spyglass] +X range
• [Sugar] +X% attack speed
• [Beam] charge time / 0.5s base attack speed / charged beam damage
• [Explosion] X explosion range / X explosion damage
• [Ice] X% slow on attack / 5s slow duration
• [Crusher] X base damage to shield icon
• [Gold] +X% gold/kill
• [Glass] X% crit chance
• [Napalm] X% true damage fire DOT

Player Tooling

Inside an active session the player gets:

• A guide book (slot 0)
• Basic Tower and Barricade in the lower hotbar (slots 1, 2)
• Upgrade, Sell, and Next Wave tools (slots 6, 7, 8)
• The main inventory rows above mirror the hotbar and hold the support tower roster: a guide book, Basic Tower, and Barricade again (slots 9-11), the nine support towers (slots 12-20), and Upgrade, Sell, and Next Wave again (slots 33-35)

Right-clicking with a tower item builds it on the targeted grid square. Right-clicking with the Upgrade or Sell tool acts on the targeted tower square. Right-clicking with the Next Wave tool ends the construction phase early — that one works no matter where you are looking, since it does not need a target block. The other tools tell you to look at a block in the play area if your crosshair is on empty sky.

Targeting uses a 300-block ray trace, and right-clicks are throttled to one every 5 ticks per player.

While you hold a tower, Upgrade, or Sell item, the action bar continuously shows the relevant price (refreshed every 5 ticks):

• holding a tower item — that tower's current cost (surcharge included), next to your gold, green when you can afford it and red when you cannot
• holding Upgrade while looking at a tower — that tower's upgrade cost, next to your gold, with the same green/red affordability colouring
• holding Sell while looking at a tower — that tower's sell value only. This line is always green and does not show your gold total, because a sale pays you rather than costing you

What Happens to Your Own Items

Entering a level snapshots your inventory contents, game mode, fly speed, flight permission, flying state, and scoreboard. The snapshot is taken before the teleport into the instance world, because mid-teleport the server reports the dimension-change grace state instead of your own. During the match you are set invulnerable and flying at fly speed 0.3.

Leaving the level — whether you win, lose, quit, use /etd hub, or the session fails to start — restores all of it. You are put back into the game mode you arrived in rather than being forced into survival, and the snapshot is dropped once restored so a second restore cannot wipe your items.

Two details about invulnerability specifically:

• Invulnerability is not part of the snapshot any more. It is cleared unconditionally on exit rather than restored from a captured value, because a captured value could pin an affected player invulnerable permanently once it was written into their playerdata.
• If no snapshot survives (for example the plugin was reloaded mid-match), EternalTD still force-clears the match state — invulnerability off, fly speed back to 0.1, and flight removed unless you are in creative or spectator — so a player can never be stranded flying or invulnerable.