rdInst Tutorial 11.3 – Simple VAT Spawning
Last Updated: 4th March 2026
Tutorial created using rdInst version 1.53
This tutorial shows how to set up a rdEntity DataAsset to use as a simple VAT entity and how to spawn from that.
Step 1. Set the Instance Settings
Firstly, we want to set up the settings used by the VAT ISMs – basically, we just want to turn off collision, turn on WPO velocities (helps remove movement smear in TSR modes) and set the number of Custom Floats to 4 (used by the VAT animation shader).
Right-Click on the VAT Static Meshes and choose rdInst->Instance Settings
Set the settings to be like these:
Note: Any time you recreate the StaticMesh, you’ll need to repeat this step.
Step 2. Create the edEntity DataAsset
Right-Click in an empty part of a Content Browser File List and Select New Miscellaneous->DataAsset from the list
Search for “rdentity” and select the “rdEntityDescriptionDataAsset”.
Open it up and set it as below:
This describes the VAT along with it’s animations and movement type.
The VAT Offset is applied to the ISM after all other calculations.
The AnimDescriptions are a way to generically assign lists of anims for each movement type a movement class caters for. The ChaseMovement has 2, an Idle set and a Chase set. Each Entity spawned takes a random anim from each set and uses those (for variation). Each item in those sets just describes the start and stop frames for that anim in the VAT textures.
The Proxy Actor Class is the Class of the NPC to use up close (or around impacts) – this can be null, in which case just the VAT will be used. If this is set and the VAT/ISM is null – just this Actor will be spawned.
The Proxy Offset is the difference between the VAT/ISM pivot and the Proxies pivot. Normally the pivot is set at the center/bottom for the ISMs – Characters have Collision Capsules where the pivot is in the center/center – so the difference between the Capsule Half-height with the VAT Offset can be added to Z here.
The Preferred Movement is the movement class to use for this Entity Type (can be overridden from the Spawn functions).
Proxy Remains Proxy can be ticked if you want to the Entity to remain as Proxy after its first swap.
Don’t Destroy Proxy when ticked, swaps back to the VAT/ISM at distance, but keeps the Proxy Actor in a dormant state associated with this Entity. This can be used for GAS Identification etc.
The Spawn Anim can be none, a “raise from the ground” or a “Fall from the sky”, taking between Spawn Anim Time Min and Max, and starting from it’s spawn location + Spawn Anim Offset.
The Spawn Weight is for when you’re spawning from a list of Entity Types, this weight (between -1.0 and 1.0) can be use to control which get spawned more/less.
You can also control spawning weight (how often Entities get spawned close to players) from the Players themselves, implement a function called “rdGetPlayerWeight” and tick “Call in Editor” property, give it 2 return values, playerChaseWeight (used to weight the Chase towards players) and playerSpawnWeight (the weight to control how many spawn around this player).
The Min and Max Scales Allows you to eith give a constant scale, or random scale in this range. Lock Scale uses the X value for all 3 axis.
Look at Player spawns the Entities all looking at their closest player or point.
Use ECS Movement for Proxy gets the ECSsyncComponent to handle moving the NPC around rather than needing CMCs or Controllers.
Step 3. Add a NavMesh and an ECS Spawn Volume
The ChaseMovement class uses an existing NavMesh to build it’s own nav cache, so firstly add a Nav Volume to the level and position/scale it to cover the area you’re wanting to move around.
Then add a rdNPCSpawnActor Volume to the level and position/scale it to cover the NavMesh.
If you’re wanting MultiPlayer, make sure to enable “Client Side Navigation” in your Project Settings->Engine->Navigation System:
Step 4. Spawn some Entities
The rdInst Subsystem has all the functions needed to work with the rdEntity System. These spawns should be called on each client (and server) and not be replicated. The players themselves will be synchronized between clients and any Proxies are replicated, but the ECS system should be run on each client to avoid unnecessary network traffic for potentially tens of thousands of Entities.
Here is a simple SpawnMultiAroundPlayers – randomly chooses from the list of Entity Descriptors and spawns between inner and outer radii (non-intersecting) around the players.
To control which players to spawn around, you can use the Function mentioned in Step 2.
By default, all the Player Spawn Weights are 0 – when they are, no weighting is used. If any are non-zero all players become weighted. To only spawn around one player, just return 1.0 for its weight while still returning 0.0 for the others – you can use 1.0 on as many as the players as you want.
To spawn more on some players and less on others, set the ones you want more spawned around as 1.0 and for the ones with less, something like 0.5 or 0.3.
If you’re only wanting to spawn 1 type of Entity, there’s the “rdSpawnAroundPlayers” as well.
If you’re wanting to spawn around a specific point rather than the players, there are the rdSpawnAroundPoint and rdSpawnMultiAroundPoint.
The rest aren’t implemented yet, but there will also be:
There will also be routines to load/remove baked NPC data at runtime.