# VkPartitionedAccelerationStructureInstanceFlagBitsNV(3) Manual Page

## Name

VkPartitionedAccelerationStructureInstanceFlagBitsNV - Bitmask specifying flags for PTLAS instances

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## C Specification

Bits which can be set in VkPartitionedAccelerationStructureWriteInstanceDataNV::`instanceFlags`, specifying flags for instances, are:

    // Provided by VK_NV_partitioned_acceleration_structure
    typedef enum VkPartitionedAccelerationStructureInstanceFlagBitsNV {
        VK_PARTITIONED_ACCELERATION_STRUCTURE_INSTANCE_FLAG_TRIANGLE_FACING_CULL_DISABLE_BIT_NV = 0x00000001,
        VK_PARTITIONED_ACCELERATION_STRUCTURE_INSTANCE_FLAG_TRIANGLE_FLIP_FACING_BIT_NV = 0x00000002,
        VK_PARTITIONED_ACCELERATION_STRUCTURE_INSTANCE_FLAG_FORCE_OPAQUE_BIT_NV = 0x00000004,
        VK_PARTITIONED_ACCELERATION_STRUCTURE_INSTANCE_FLAG_FORCE_NO_OPAQUE_BIT_NV = 0x00000008,
        VK_PARTITIONED_ACCELERATION_STRUCTURE_INSTANCE_FLAG_ENABLE_EXPLICIT_BOUNDING_BOX_NV = 0x00000010,
    } VkPartitionedAccelerationStructureInstanceFlagBitsNV;

## Description

- `VK_PARTITIONED_ACCELERATION_STRUCTURE_INSTANCE_FLAG_TRIANGLE_FACING_CULL_DISABLE_BIT_NV` disables face culling for this instance.

- `VK_PARTITIONED_ACCELERATION_STRUCTURE_INSTANCE_FLAG_TRIANGLE_FLIP_FACING_BIT_NV` specifies that the facing determination for geometry in this instance is inverted.

- `VK_PARTITIONED_ACCELERATION_STRUCTURE_INSTANCE_FLAG_FORCE_OPAQUE_BIT_NV` causes this instance to act as though `VK_GEOMETRY_OPAQUE_BIT_KHR` were specified on all geometries referenced by this instance.

- `VK_PARTITIONED_ACCELERATION_STRUCTURE_INSTANCE_FLAG_FORCE_NO_OPAQUE_BIT_NV` causes this instance to act as though `VK_GEOMETRY_OPAQUE_BIT_KHR` were not specified on all geometries referenced by this instance.

- `VK_PARTITIONED_ACCELERATION_STRUCTURE_INSTANCE_FLAG_ENABLE_EXPLICIT_BOUNDING_BOX_NV` enables use of an explicit bounding box for this instance.

## See Also

VK_NV_partitioned_acceleration_structure, VkPartitionedAccelerationStructureInstanceFlagsNV

## Document Notes

For more information, see the Vulkan Specification

This page is extracted from the Vulkan Specification. Fixes and changes should be made to the Specification, not directly.

## Copyright

Copyright 2014-2025 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0