rdBPtools Tutorial 5.1 – Introduction to SIDs
Last Updated: 2nd March 2025
Tutorial created using rdBPtools version 1.41
Sids are a way of describing a Static Mesh along with some its rendering settings such as Material Overrides, Reverse Culling, Culling Distances, Spawn Type, Collision, a Unique ID, and a Group name.
They’re stored as Names (FNames) so have a maximum length of 1024 characters. The soft-reference paths are compressed to save character lengths. Note that as FNames the filenames are stored as case insensitive, so if you’re using Linux on a LFS drive, ensure all your folders are lower case (good practice to avoid other issues too).
There are various ways of building sids – from existing StaticMeshes, StaticMeshComponents, Actors, DataLayers and rdInstance classes, or building them manually from one of the Make functions. In rdInst you have functions to spawn any sid just from its sid.
When Actors are stored as sids, their properties (for the main actor types) are also stored in the sid. When serializing, using sids instead of serializing whole actors, it can be much more efficient – both disk footprint/memory size but also speed. Also, when using sids you can cluster your various objects into their sids to create and easy and extremely efficient system of storing/spawning/manipulating your scenes objects.
Both rdBPtools and rdInst build their reference tables from sids now – they’re even slightly faster than the previous system and require very little memory and setup overhead.
Another benefit to sids is that they’re in essence – soft pointers, so no resources are loaded until the asset is used in the prefab, no objects that are hidden are loaded until shown.
Sids can describe Meshes, Actors, DataLayers, Levels and is easily added upon without breaking compatibility.
The sids also contain an “id” which can be used to separate those sids from others – and also Groups which can be used to group as many different sids into the same categories for editing or runtime manipulation.
From within rdPrefabs you have the following nodes available to work with sids:
To work with either the stored prefab item data or the Instance Component directly you can find the specific data by using the sid as the key (To access instListX and ismcListX you’ll need to untick “context sensitive” as they’re hidden):
