Room markers are simple shapes which define an area as a room. Rooms, in essence, act as collectors. When culling, the renderer will treat everything inside another room as invisible, saving valuable processing power.

–Bethesda Tutorial Optimization

Preface

Optimized Room Bounds & Portals or just ORBP alters/removes PreVis and Combined references from interior cells and thus force the game to use Room Bounds and Portals. Room Bounds and Portals are much more optimized tools to increase performance on user end. Since, it allows to cut off a lot of rendering, due to not rendering sections of the interior that are beyond the current Defined Room, only rendering the space beyond fully, when player goes through the Room Portal. This technique was probably dropped during development of FO4 at some point since its time consuming to setup.

Some Fallout 4 interios have Room Bounds and Portals available but almost all interiors cells use PreVis and Combination, which probably override Portals and Room Bounds. Since its far less time consuming to generate Combined and PreVis meshes, Room Bounds and Portals can be seen as a leftover in the game files, references.

During development on this mod, i noticed many (leftover) Room Bounds were inproper setup and did not cover the entire area or had misplaced Portal(s). This was fixed. Furthermore, i figured that Room Bounds net into an even more compact cluster increase FPS so much, i could not believe. This was done on an iGPU to instantly notice slight changes on FPS. My observation proofed to outclass the PreVis and Combination logic for interiors totally. Since then, the idea of this mod was born.

The foundation was led to purge the Cell Header and make room for Room Bounds and Portals ... By removing the PreVis and PreCombine references the game directly unflags the former Combined statics to be true Placed Objects. Just like any other object class. This would make the mod best suitable for modders since it allows to alter the entire cell, all objects!

Overview

In short this mod ...

- Affects Interior Cells
- Alters PreVis
⠀- Adds the "No PreVis" flag to ALL interior cells
⠀- Blanks PreVis Files Timestamp (VISI)
⠀- Blanks PreVis Reference Index (XPRI)
- Alters PreCombination
⠀- Blanks PreCombined Files Timestamp (PCMB)
⠀- Blanks Combined Reference Index (XCRI)
- Unflags static objects: "[Placed Object]" to "Placed Object"
- Increases performance due to Room Bounds and Portal
⠀- Optimizes Room Bounds and Portals (WIP)
⠀- Adds missing Room Bounds and Portals (WIP)
- Build around stable 60 FPS on an iGPU setup

Installation

This mod can be in-/unstalled anytime and does not require a new game to work.

It should be loaded very last, otherwise manual patching is required (Details in the "Developer Notes" section below).

The plugin is NOT flagged ESL. It can corrupt the game from using Room Bounds and Portals.

This mod affects Pre Combined meshes and/or Pre Vis data.

Compatibility

This mod works with both, the Old- and Next-Gen Update.

For third party mods ask the author of the mod of interest.

NOTE: Mods which alters Cell Header or Room Bounds and Portals require a patch.

Developer Notes

The following must be done in order to patch the interior cells, yet part of the mod:

In written text, you should patch:
- Add "No Pre Vis" flag to the "Record Flags (sorted) tab
- Remove/blank VISI and PCMB entries
- Remove/blank XPRI - PreVis Reference Index (sorted)
- Remove/blank XCRI - Combined Reference Index

All of this is valid for the Cell Header in the object class CELL.

Credits

- Bethesda
- FO4Edit Team, for their invaluable tool
- Nexus Community;
⠀- PJMail and niston for initial support
⠀- B00tx, hikdid, LoveCters, Ouroboros1988, Stormpriest1066, TheDogDismemberer88, Zeldoris57 for bug reports
- ARJAFIELD and SneakyGuyX for video presentation:


References

- https://ck.uesp.net/wiki/Room_Bounds_and_Portal_Basics
- https://ck.uesp.net/wiki/Bethesda_Tutorial_Optimization#Room_Markers_and_Portals
- https://geckwiki.com/index.php/Room_Bounds_and_Portal_Basics
- https://geckwiki.com/index.php/Editing_MultiBounds
- Precombine Previs Deep Dive: https://www.nexusmods.com/fallout4/articles/4316
- https://forums.nexusmods.com/topic/5522717-fallout-4-optimization-and-performance-systems-explained
- https://www.nexusmods.com/fallout4/mods/69978
- https://www.nexusmods.com/fallout4/mods/84717
- https://www.reddit.com/r/skyrimmods/comments/1ew0hyn/using_room_bounds_and_portals_to_solve_a/
- https://www.reddit.com/r/skyrimmods/comments/16x6ooj/roombound_portals_and_rendering_question/
- https://www.reddit.com/r/skyrimmods/comments/4f6fdb/questions_about_occlusion_planeboxes_culling_and/
- https://www.reddit.com/r/skyrimmods/comments/18dp5nk/how_do_i_reduce_draw_calls/
- https://simsettlements.com/site/index.php?threads/how-necessary-useful-are-room-bounds-optimization-questions.23224/
- https://www.afkmods.com/index.php?/topic/9692-occlusion-planes-vs-roomboundportal-how-are-they-different-which-should-i-use/
- Skyrim Project Optimization SE