Add new target point bone for Seraphim destroyer

[lL1l1]

Issue

Players have reported Exodus projectiles seeming to fly straight through Seraphim destroyers. Specifically in replay 26577440 at 13:10 on the left side of the map there are 2 projectiles that fly just a bit over the top of the Seraphim destroyer's hitbox, which looks as if it went straight through from the normal top-down perspective. This is particularly weird because the Exodus has the best accuracy out of all destroyers (even more so after the recent buff) with only 0.2 firing randomness, and in the replay the destroyer wasn't even at maximum range.

Upon detailed investigation, I noticed using dbg c (shows hitboxes as blue boxes) and dbg_CollisionBeam (shows collision beams as green lines) that Seraphim destroyers firing at Seraphim destroyers were not aiming at the center of the hitbox, but towards the top of it.

With further testing, it is evident that the engine's default aim point when no target bone is specified does not account for CollisionOffsetY:

This means that with the Seraphim destroyer's hitbox of 1.3 SizeY and -0.4 CollisionOffsetY, the engine was aiming at Y = 0.65, with only 0.25 hitbox height above the aim point, while in reality the center is located at Y 0.25, and the above-water center is at 0.45.

This tiny hitbox height above the aim point explains why players were seeing Exodus shots fly over the top of Seraphim destroyers so often that they noticed it and reported it.

Description of the proposed changes

Add a new bone at height 9 in the mesh or 0.45 translated using the unit's UniformScale of 0.05, and assigns it as a target bone. This places it in the center of the above-water hitbox, giving the greatest chance to hit.

A new bone is necessary because the root bone is at height 0 which ends up being underwater, and thus not allowed to be target by most weapons.

Testing done on the proposed changes

Using the same collision box and beam debugging before, the weapon aims at the bone as expected, and this is noticeably lower than the default aim point.

The beam not aiming at exactly the aim point is a separate issue.

Checklist

• Changes are annotated, including comments where useful
• Changes are documented in a changelog snippet according to the guidelines.
• Request 2-3 reviewers from the list of reviewers and their areas of knowledge.

Summary by CodeRabbit

• Bug Fixes

  • Reduced projectile overshooting for the Seraphim Uashavoh (T2 Destroyer) by adjusting its aim point for more consistent hits.

• Documentation

  • Clarified how unit target points are chosen, making aiming behavior easier to understand.

[coderabbitai]

Caution

Review failed

The pull request is closed.

ℹ️ Recent review info

Configuration used: defaults

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 5f60aa6 and 4146181.

📒 Files selected for processing (1)

• changelog/snippets/balance.7056.md

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📝 Walkthrough

Walkthrough

Adds an AI.TargetBones entry to the Seraphim T2 destroyer (XSS0201), updates UnitBlueprint comments clarifying TargetBones/center position, and adds a changelog noting a lowered above-water aim elevation to reduce shot overshoot.

Changes

Cohort / File(s)	Summary
Changelog Entry changelog/snippets/balance.7056.md	Added changelog describing reduced overshoot by lowering above-water aim elevation for Uashavoh (XSS0201).
Blueprint Documentation engine/Core/Blueprints/UnitBlueprint.lua	Reworded comments around TargetBones and clarified center position calculation uses Size but not CollisionOffset (comment-only changes).
Unit Configuration units/XSS0201/XSS0201_unit.bp	Added AI.TargetBones array with {"XSS0201", "Center_Target"} to the XSS0201 UnitBlueprint.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Possibly related PRs

• Add new target point bone for Seraphim destroyer #7056: Modifies the same units/XSS0201/XSS0201_unit.bp to add AI.TargetBones and includes the same changelog/comment updates.
• Strat agility buff #6535: Adds/expands TargetBones usage in UnitBlueprints (air units) and related docs; relates to the same blueprint field.
• Make antitorps more effective against the Seraphim destroyer #7015: Other recent edits to units/XSS0201/XSS0201_unit.bp (torpedo/weapon stat changes) touching the same unit blueprint.

Suggested reviewers

• Basilisk3
• Rhaelya

Poem

🐇 I nudged the bones where aim must be,
Waves hush, the targets breathe with me,
Torpedoes curve, then kiss the sea,
Little changes, steady glee,
Hop, hop — balance for the fleet!

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately describes the main change: adding a new target point bone for the Seraphim destroyer to fix aiming issues.
Description check	✅ Passed	The description includes detailed issue context, clear explanation of changes, testing performed, and a completed checklist with all required sections filled.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@changelog/snippets/balance.7056.md`:
- Line 3: Fix the unit ID typo in the changelog entry by replacing the incorrect
identifier XSL0201 with the correct XSS0201 in the "Uashavoh: T2 Destroyer"
line; update the text so it references XSS0201 (Seraphim destroyer) consistently
to avoid confusion for players and contributors.

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ℹ️ Review info

Configuration used: defaults

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 72a00be and 4f2c111.

📒 Files selected for processing (4)

• changelog/snippets/balance.7056.md
• engine/Core/Blueprints/UnitBlueprint.lua
• units/XSS0201/XSS0201_lod0.scm
• units/XSS0201/XSS0201_unit.bp

[coderabbitai]

🧹 Nitpick comments (1)

changelog/snippets/balance.7056.md (1)

4-4: Clarify the measurement notation in parentheses.

The parenthetical notes "(0.25 height of hitbox above)" and "(0.45 height of hitbox above)" are ambiguous. It's unclear whether these represent absolute elevations, fractions of the hitbox height, distances from a reference point, or something else.

Consider revising to be more explicit, for example:

• "0.65 (72% up the above-water hitbox) -> 0.45 (50% up the above-water hitbox)"
• "0.65 (0.4 above hitbox center) -> 0.45 (0.2 above hitbox center)"
• Or simply: "0.65 -> 0.45" without the parenthetical if it doesn't add clarity

This will help players and developers better understand the technical change.

📝 Example revision options

Option 1 - Remove ambiguous notation:

-  - Aim point above-water elevation: 0.65 (0.25 height of hitbox above) -> 0.45 (0.45 height of hitbox above)
+  - Aim point elevation: 0.65 -> 0.45 (centered on above-water portion)

Option 2 - Use percentage of above-water hitbox:

-  - Aim point above-water elevation: 0.65 (0.25 height of hitbox above) -> 0.45 (0.45 height of hitbox above)
+  - Aim point above-water elevation: 0.65 (72% up) -> 0.45 (50% up, centered)

Option 3 - Use absolute distance above water line:

-  - Aim point above-water elevation: 0.65 (0.25 height of hitbox above) -> 0.45 (0.45 height of hitbox above)
+  - Aim point elevation: 0.65 (0.65 above water) -> 0.45 (0.45 above water)

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@changelog/snippets/balance.7056.md` at line 4, The parenthetical notes in the
line "Aim point above-water elevation: 0.65 (0.25 height of hitbox above) ->
0.45 (0.45 height of hitbox above)" are ambiguous; update that line to clearly
state what the parentheses represent (e.g., percentage of the above-water hitbox
height, absolute distance from the hitbox center, or distance above the
waterline) or remove them if unnecessary—for example replace with "Aim point
above-water elevation: 0.65 (72% up the above-water hitbox) -> 0.45 (50% up the
above-water hitbox)" or simply "Aim point above-water elevation: 0.65 -> 0.45".
Ensure the chosen wording uses consistent units/terms and matches other
changelog entries.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Nitpick comments:
In `@changelog/snippets/balance.7056.md`:
- Line 4: The parenthetical notes in the line "Aim point above-water elevation:
0.65 (0.25 height of hitbox above) -> 0.45 (0.45 height of hitbox above)" are
ambiguous; update that line to clearly state what the parentheses represent
(e.g., percentage of the above-water hitbox height, absolute distance from the
hitbox center, or distance above the waterline) or remove them if
unnecessary—for example replace with "Aim point above-water elevation: 0.65 (72%
up the above-water hitbox) -> 0.45 (50% up the above-water hitbox)" or simply
"Aim point above-water elevation: 0.65 -> 0.45". Ensure the chosen wording uses
consistent units/terms and matches other changelog entries.

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ℹ️ Review info

Configuration used: defaults

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 4f2c111 and 5f60aa6.

📒 Files selected for processing (1)

• changelog/snippets/balance.7056.md