---
name: "RTCRay"
section: "3embree4"
platform: "linux"
package: "embree"
version: "4.4.1-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/RTCRay/3embree4"
---

# RTCRay(3embree4)

### NAME

-

  ```
  RTCRay - single ray structure
  ```

### SYNOPSIS

-

  ```
  #include <embree4/rtcore_ray.h>
  struct RTC_ALIGN(16) RTCRay
  {
    float org_x;        // x coordinate of ray origin
    float org_y;        // y coordinate of ray origin
    float org_z;        // z coordinate of ray origin
    float tnear;        // start of ray segment
    float dir_x;        // x coordinate of ray direction
    float dir_y;        // y coordinate of ray direction
    float dir_z;        // z coordinate of ray direction
    float time;         // time of this ray for motion blur
    float tfar;         // end of ray segment (set to hit distance)
    unsigned int mask;  // ray mask
    unsigned int id;    // ray ID
    unsigned int flags; // ray flags
  };
  ```

### DESCRIPTION

The `RTCRay` structure defines the ray layout for a single ray. The ray contains the origin (`org_x`, `org_y`, `org_z` members), direction vector (`dir_x`, `dir_y`, `dir_z` members), and ray segment (`tnear` and `tfar` members). The ray direction does not have to be normalized, and only the parameter range specified by the `tnear`/`tfar` interval is considered valid.

The ray segment must be in the range \[0, ∞\], thus ranges that start behind the ray origin are not allowed, but ranges can reach to infinity.

The ray further contains a motion blur time in the range \[0, 1\] (`time` member), a ray mask (`mask` member), a ray ID (`id` member), and ray flags (`flags` member). The ray mask can be used to mask out some geometries for some rays (see `rtcSetGeometryMask` for more details). The ray ID can be used to identify a ray inside a callback function, even if the order of rays inside a ray packet has changed.

The `embree4/rtcore_ray.h` header additionally defines the same ray structure in structure of array (SOA) layout for API functions accepting ray packets of size 4 (`RTCRay4` type), size 8 (`RTCRay8` type), and size 16 (`RTCRay16` type). The header additionally defines an `RTCRayNt` template for ray packets of an arbitrary compile-time size.

### EXIT STATUS

### SEE ALSO

\[RTCHit\]