Tracing

Namespace: DeadworksManaged.Api

Cast rays and shapes through the world using the VPhys2 physics system. Useful for hit detection, line of sight, and collision checks.

Trace (Static Class)

All methods are no-ops if the physics query system is not yet ready.

Simple Ray Cast

Fire a line ray from start to end:

var result = Trace.Ray(
    start: pawn.EyePosition,
    end: pawn.EyePosition + forwardDirection * 1000f,
    mask: MaskTrace.Solid,
    ignore: pawn  // skip the casting entity
);

if (result.DidHit)
{
    Console.WriteLine($"Hit at {result.HitPosition}, fraction: {result.Fraction}");
}

TraceShape (Advanced)

Full control with custom ray shape and filter:

var ray = new Ray_t();
// Initialize ray shape...

var filter = new CTraceFilter();
// Configure filter...

CGameTrace trace;
Trace.TraceShape(start, end, ray, filter, out trace);

if (trace.DidHit)
{
    var hitEntity = trace.HitEntity;
    Console.WriteLine($"Hit: {hitEntity?.Classname} at {trace.HitPoint}");
}

SimpleTrace

Convenience method that builds the filter and ray from parameters:

CGameTrace trace;
Trace.SimpleTrace(
    start, end,
    RayType_t.Line,
    RnQueryObjectSet.All,
    interactMask, solidMask, triggerMask,
    CollisionGroup.Default,
    out trace,
    ignoreEntity1: pawn,
    ignoreEntity2: null
);

SimpleTraceAngles

Like SimpleTrace but uses pitch/yaw angles instead of an end point:

CGameTrace trace;
Trace.SimpleTraceAngles(
    origin, angles,
    RayType_t.Line,
    RnQueryObjectSet.All,
    interactMask, solidMask, triggerMask,
    CollisionGroup.Default,
    out trace,
    ignoreEntity1: pawn,
    ignoreEntity2: null,
    maxDistance: 5000f
);

Trace Methods Summary

Method	Description
Ray(Vector3 start, Vector3 end, MaskTrace mask, CBaseEntity? ignore)	Simple line ray, returns TraceResult
TraceShape(Vector3, Vector3, Ray_t, CTraceFilter, out CGameTrace)	Full shape trace with custom ray and filter
SimpleTrace(...)	Convenience with individual parameters
SimpleTraceAngles(...)	Like SimpleTrace but with angles and max distance

TraceResult

Simplified result from Trace.Ray():

Property	Type	Description
DidHit	bool	Whether the ray hit something
HitPosition	Vector3	World position of the hit
Fraction	float	0.0 (at start) to 1.0 (at end) — how far the ray traveled
Trace	CGameTrace	Full trace data

CGameTrace

Full result of a VPhys2 shape trace:

Member	Type	Description
DidHit	bool	Whether the trace hit something
HitPoint	Vector3	World position of the hit
HitNormal	Vector3	Surface normal at hit point
HitEntity	CBaseEntity?	Entity that was hit

Ray Shapes

RayType_t

Shape type for trace queries:

Value	Description
Line	Line ray (default)
Sphere	Sphere shape
Hull	AABB hull
Capsule	Capsule shape

Shape Data Structs

Struct	Description
LineTrace	Line ray with optional radius (swept sphere)
SphereTrace	Sphere at a fixed center point
HullTrace	AABB hull swept along a ray
CapsuleTrace	Capsule between two center points with radius
MeshTrace	Convex mesh with bounds and vertices

Collision Filtering

CollisionGroup

Determines which objects interact in physics simulation.

InteractionLayer

Individual content/interaction layers for building trace bitmasks.

MaskTrace

Bitmask combining InteractionLayer values:

Value	Description
Solid	Solid world geometry
(others)	Various content layer combinations

RnQueryObjectSet

Controls which object sets are included:

Value	Description
All	All object sets (static, dynamic, locatable)

CTraceFilter

Full trace filter with entity-aware filtering:

var filter = new CTraceFilter(true) {
    IterateEntities = true,
    QueryShapeAttributes = new RnQueryShapeAttr_t {
        ObjectSetMask = RnQueryObjectSet.All,
        InteractsWith = MaskTrace.Solid,
        InteractsExclude = MaskTrace.Empty,
        InteractsAs = MaskTrace.Empty,
        CollisionGroup = CollisionGroup.CitadelBullet,
        HitSolid = true,
    }
};
// Ignore specific entities by index (requires unsafe)
unsafe {
    filter.QueryShapeAttributes.EntityIdsToIgnore[0] = (uint)pawn.EntityIndex;
}

RnQueryShapeAttr_t

Query attributes for shape traces:

Property	Type	Description
ObjectSetMask	RnQueryObjectSet	Which object sets to query
InteractsWith	MaskTrace	What the ray interacts with
InteractsExclude	MaskTrace	What to exclude from interaction
InteractsAs	MaskTrace	What the ray acts as
CollisionGroup	CollisionGroup	Collision group for filtering
HitSolid	bool	Whether to hit solid objects
HitTrigger	bool	Whether to hit trigger volumes
EntityIdsToIgnore	fixed uint[2]	Up to 2 entity indices to skip (requires unsafe)

Trace.Ray hits trigger volumes

Trace.Ray with MaskTrace.Solid will hit trigger volumes like CPostProcessingVolume, returning DidHit=True with Fraction=0.000 if the ray starts inside one. For line-of-sight checks, use TraceShape with a CTraceFilter configured with CollisionGroup.CitadelBullet and HitSolid = true (without HitTrigger).

Example: Line-of-Sight Check

Bullet-style LOS check that ignores trigger volumes and specific entities:

var trace = CGameTrace.Create();
var ray = new Ray_t { Type = RayType_t.Line };
var filter = new CTraceFilter(true) {
    IterateEntities = true,
    QueryShapeAttributes = new RnQueryShapeAttr_t {
        ObjectSetMask = RnQueryObjectSet.All,
        InteractsWith = MaskTrace.Solid,
        InteractsExclude = MaskTrace.Empty,
        InteractsAs = MaskTrace.Empty,
        CollisionGroup = CollisionGroup.CitadelBullet,
        HitSolid = true,
    }
};
unsafe {
    filter.QueryShapeAttributes.EntityIdsToIgnore[0] = (uint)sourcePawn.EntityIndex;
    filter.QueryShapeAttributes.EntityIdsToIgnore[1] = (uint)targetPawn.EntityIndex;
}
Trace.TraceShape(sourcePawn.EyePosition, targetPawn.EyePosition, ray, filter, ref trace);

bool hasLos = !trace.DidHit;
// trace.HitEntity?.Classname tells you what blocked (e.g. "CWorld" for walls)

note

EntityIdsToIgnore is a fixed-size buffer — accessing it requires unsafe code and <AllowUnsafeBlocks>true</AllowUnsafeBlocks> in your .csproj.

Example: Player Eye Trace

From the Deathmatch plugin:

[ChatCommand("trace")]
public HookResult OnTrace(ChatCommandContext ctx)
{
    var pawn = ctx.Controller?.GetHeroPawn();
    if (pawn == null) return HookResult.Handled;

    var result = Trace.Ray(
        pawn.EyePosition,
        pawn.EyePosition + ForwardFromAngles(pawn.EyeAngles) * 5000f,
        MaskTrace.Solid,
        pawn
    );

    if (result.DidHit)
    {
        ctx.Controller.PrintToConsole($"Hit at {result.HitPosition}");
        ctx.Controller.PrintToConsole($"Distance: {result.Fraction * 5000f} units");
    }

    return HookResult.Handled;
}

See Also

• Entities — Entity references in trace results
• Players — EyePosition, EyeAngles, ViewAngles
• Deathmatch Example — Trace system in practice