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. The reference below lists the effective runtime values.

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

The placement event announces the surcharge when the existing tower count is a nonzero multiple of 15, before the new tower is added. This is not a notification at every price change, and a later cancelled placement can still have produced the message.

The upgrade cost is 4 × the tower's stored cost; that stored value starts at the base price and is multiplied by 4 on every upgrade, without the surcharge. Selling after the first 5 seconds returns 75% of the current cost, including the surcharge calculated before removal, truncated to an integer. During those first 5 seconds it returns only the recorded placement price, even if you upgraded the tower meanwhile. Cheat mode records no placement payment, so that early refund is zero. Build and upgrade still check affordability in cheat mode but skip charging.

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 an ItemDisplay holding an arrow item, steered toward the target each tick; damage is applied manually when its squared distance to the target's eyes is below 1.5. It does not use normal arrow collision or line-of-sight checks. The scanner keeps a valid in-range target, otherwise choosing the first spawned in-range enemy in the wave list. Range is measured in 3D from the grid square, so airborne height matters.

Real firing cadence

The tower's scan loop fires once per computed attack interval: every 40 ticks (2 seconds) at base. With a Beam Generator attached, the base interval is 5 ticks (0.25 seconds). Sugar attack-speed bonuses shorten either interval, which never drops below 1 tick.

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 Basic Towers in the eight adjacent grid squares, including diagonals. Contributions from multiple supports add together, subject to the caps below.

Placing, upgrading or removing a support tower recalculates the neighboring Basic Towers at once, so an upgrade's new increment and the bonus display tags apply immediately. Removing the last elemental support returns the Basic Tower to its own Unattuned element.

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:
  • Without Sugar bonuses, the beam fires every 5 ticks (0.25 seconds). The Beam Generator's item lore ("0.25s per attack") and the tower's [Beam] 0.25s base attack speed tag show this base rate. The tower's Attack Speed tag includes Sugar bonuses.
  • Damage starts near 1/8 of the tower's damage and grows exponentially while hitting the same target. Changing targets resets the warmup.
  • Reaching full charge against the same target takes the displayed charge time: 3 seconds with one generator. The warmup counter advances by the attack interval on each shot.
  • Fully charged damage uses a 3× multiplier on the tower's damage before other modifiers. The floating charged beam damage tag shows that fully charged hit: the tower's damage × 3, divided by 4 when an Explosion Factory is attached. It leaves out elemental and critical modifiers, which depend on the target.
• 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.
• The direct hit triggers splash instead of a separate primary-target hit. Spawned wave enemies within the 3D radius, including the primary target, receive processed damage with a 1/4 multiplier. Elemental, beam and critical modifiers still apply. The item lore states the same 1/4 share.
• 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%.
• An accepted slow lasts 5 seconds. An equal or stronger slow refreshes it; a weaker slow does not replace or refresh it. Slow is applied through damage notifications, so an ordinary hit fully absorbed by armor does not apply it; later DOT notifications can.
• 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%.
• From wave 10, armor starts at maxHealth / 80. Armor Crusher removes its share of the processed hit after the Napalm split, then the remaining armor subtracts from that hit's health damage. Without armor shredding, ordinary damage does not consume armor. DOT bypasses it.

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 divides its amount into three pulses, at 3, 6 and 9 seconds after the hit. Each hit schedules its own DOT, which stops if the enemy is removed.
• Its share is subtracted from the immediate processed hit before armor is applied; it can still deal damage when armor absorbs the immediate portion.
• Total fire-DOT share is capped at 100%.

Tower Upgrade Visuals

The vanilla tower body's 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

With FMM and the required models available, levels 1–6 use stone, gold, diamond, emerald, netherite and redstone variants. Higher levels keep redstone; there is no level-6 upgrade cap in this path. Barricade uses its fixed model. Basic Tower support attachments appear and disappear when bonuses are recalculated.

Bonus Display Tags

Every placed Basic Tower gets a stack of invisible armor stands with calculated display values. The [Beam] 0.25s base attack speed line shows the beam interval before Sugar bonuses, and charged beam damage shows the fully charged hit before elemental and critical modifiers. Damage and Attack Speed are always present; other lines appear for nonzero recalculated support bonuses:

• Damage, Attack Speed (unconditional)
• [Spyglass] +X range
• [Sugar] +X% attack speed
• [Beam] charge time / 0.25s 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 a tower item requests placement on the targeted grid square; cost, valid paths and placement events must permit it. Upgrade and Sell act on that square's tower and can also be cancelled by their events. Next Wave needs no target block, but only advances from the starting or construction phase and still respects tutorial requirements. The other tools ask you to look at a play-area block if your crosshair points into 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 — current cost with surcharge next to your gold; its price text stays dark green even when unaffordable, so compare the numbers
• holding Upgrade while looking at a tower — upgrade cost next to your gold, green when affordable and red otherwise
• 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

Before teleporting into a level, EternalTD saves a recovery record in your playerdata containing your inventory, held slot, fly speed, flight permission, flying state, and return location. Your scoreboard is retained separately for restoration during the same server session. Match equipment enables flight at speed 0.3; it does not change your game mode or invulnerability flag.

Leaving or failing to start a level attempts to restore that state. On a normal exit you go back to where you were just before you entered the level, or to the main world's spawn if that world is no longer loaded. The durable record also supports recovery after a crash: it is restored on your next join and is removed only after restoration is saved successfully. Failed recovery retains the record and disconnects an online player for a later retry. Crash recovery returns you to the saved location only if its world is loaded; a rejected return is logged without undoing inventory recovery. Without an owned recovery record, EternalTD does not forcibly reset unrelated player state.