Editing Openai/69676758-d944-8003-a3d4-835e33b4e372 (section)

=== Assistant: Good — this is where many designs get vague, and where disciplined engines differ from hobby ones. ===
Good — this is where many designs get vague, and where disciplined engines differ from hobby ones.

“Space” constraints mean memory footprint and bandwidth, not disk size. You handle them with the same budgeting mindset as time.

==== Do this early, even if approximate. ====

Example PC targets:
* Minimum: - System RAM usable by game: 6–8 GB - VRAM usable by game: 3–4 GB
* Recommended: - RAM: 12–16 GB - VRAM: 6–8 GB

You never assume you own all memory. OS + drivers take a fixed cut.

==== ### ====

Typical buckets:
* World data (level geometry, navmesh)
* Gameplay state (entities, components)
* AI data
* Physics data
* Streaming buffers
* Audio buffers
* Scratch / transient allocations

Example (8 GB target):

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===== Buckets must be explicit: =====

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If you don’t reserve headroom, you will stutter or crash.

==== Now mechanics get space budgets, not just time budgets. ====

===== You define: =====
* Bytes per entity
* Maximum active entities

Example:
* NPC state: 2 KB
* Animation state: 8 KB
* AI blackboard: 4 KB → 14 KB per NPC

At 1,000 NPCs:
→ ~14 MB RAM (acceptable)

===== Define per-asset limits: =====
* Character texture set: - Albedo 2k - Normal 2k - ORM 2k → ~48 MB uncompressed, ~12–16 MB compressed
* Environment prop: - ≤ 10 MB VRAM
* Hero character: - ≤ 64 MB VRAM

Write these limits into the design.

==== Streaming trades space for bandwidth + complexity. ====

Design rules:
* Maximum streamed-in assets at once
* Maximum streaming IO per second
* Maximum latency tolerance

Example:
* World tiles: ≤ 256 MB each
* Max 3 tiles resident
* Streaming buffer: 1 GB RAM
* IO budget: ≤ 100 MB/s sustained

==== Memory size is useless without bandwidth. ====

You must budget:
* CPU cache pressure
* RAM → GPU transfers
* VRAM read/write per frame

Examples:
* Avoid per-frame full-buffer uploads
* Prefer persistent mapped buffers
* Cap particle buffer rewrites

On paper:

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==== You should not attempt to: ====
* Predict cache line utilization
* Predict exact compression ratios
* Predict residency behavior

Those are profiling-stage concerns.

==== Bad: ====

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Good:

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Bad:

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Good:

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==== Space constraints are budgets, caps, and per-unit costs. ====

If every mechanic has:
* a per-unit memory cost
* a hard cap
* a scaling rule

Then the game is designable, testable, and shippable.

If you want, I can help you turn one of your mechanics into a concrete time + space budget as an example.