UKismetMathLibrary::Matrix_GetFrustumTopPlane

function Engine Blueprint Since 4.0

#include "Kismet/KismetMathLibrary.h"

Access: public Specifiers: staticBlueprintPure

Description

Extracts the top clipping plane from a view-projection matrix. Returns false if extraction fails.

Caveats & Gotchas

• "Top" is defined in clip space, not world space — the plane's world-space normal will depend on the camera's orientation.
• For stereo rendering each eye has its own view-projection matrix; you must extract planes per-eye rather than using a single shared matrix.

Signature

static UE_INL_API bool Matrix_GetFrustumTopPlane(const FMatrix& M, FPlane& OutPlane)

Parameters

Name	Type	Description	Default
M	const FMatrix&	The view-projection matrix to extract the top frustum plane from.	—
OutPlane	FPlane&	The extracted top plane of the frustum.	—

Return Type

bool

Example

Check if a world point is below the top frustum plane C++

FPlane TopPlane;
if (UKismetMathLibrary::Matrix_GetFrustumTopPlane(ViewProjMatrix, TopPlane))
{
    bool bBelowTop = TopPlane.PlaneDot(WorldPos) >= 0.0f;
}

Version History

Introduced in: 4.0

Version	Status	Notes
5.6	stable	—

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