# VkPartitionedAccelerationStructureWriteInstanceDataNV(3) Manual Page

## Name

VkPartitionedAccelerationStructureWriteInstanceDataNV - Structure describing instance data to write in PTLAS

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## C Specification

The VkPartitionedAccelerationStructureWriteInstanceDataNV structure is defined as:

    // Provided by VK_NV_partitioned_acceleration_structure
    typedef struct VkPartitionedAccelerationStructureWriteInstanceDataNV {
        VkTransformMatrixKHR                                 transform;
        float                                                explicitAABB[6];
        uint32_t                                             instanceID;
        uint32_t                                             instanceMask;
        uint32_t                                             instanceContributionToHitGroupIndex;
        VkPartitionedAccelerationStructureInstanceFlagsNV    instanceFlags;
        uint32_t                                             instanceIndex;
        uint32_t                                             partitionIndex;
        VkDeviceAddress                                      accelerationStructure;
    } VkPartitionedAccelerationStructureWriteInstanceDataNV;

## Members

- `transform` is a VkTransformMatrixKHR structure describing the transformation to be applied to the instance in PTLAS.

- `explicitAABB` specifies an axis aligned bounding box representing the maximum extent of any vertex within the used acceleration structure after applying the instance-to-world transformation. The partition translation is not applied to the bounding box.

- `instanceID` is a user specified constant assigned to an instance in the PTLAS.

- `instanceMask` is a 8-bit mask assigned to the instance that may be used to include or reject group of instances.

- `instanceContributionToHitGroupIndex` is a 24-bit per application specified instance value added in the indexing into the shader binding table to fetch the hit group to use.

- `instanceFlags` is a bitmask of VkPartitionedAccelerationStructureInstanceFlagsNV specifying flags an instance in the PTLAS.

- `instanceIndex` is the index of the instance within the PTLAS.

- `partitionIndex` is the index of the partition to which this instance belongs. Global partitions are referred to by `VK_PARTITIONED_ACCELERATION_STRUCTURE_PARTITION_INDEX_GLOBAL_NV`.

- `accelerationStructure` is the device address of the bottom level acceleration structure or a clustered bottom level acceleration structure that is being instanced. This instance is disabled if the device address is `0`.

## Description

Valid Usage

- VUID-VkPartitionedAccelerationStructureWriteInstanceDataNV-instanceMask-10566
  The most significant 24 bits of `instanceMask` must be `0`

- VUID-VkPartitionedAccelerationStructureWriteInstanceDataNV-instanceContributionToHitGroupIndex-10567
  The most significant 8 bits of `instanceContributionToHitGroupIndex` must be `0`

- VUID-VkPartitionedAccelerationStructureWriteInstanceDataNV-instanceIndex-10568
  `instanceIndex` must be less than VkBuildPartitionedAccelerationStructureInfoNV::`input`::`instanceCount`

- VUID-VkPartitionedAccelerationStructureWriteInstanceDataNV-partitionIndex-10569
  `partitionIndex` must be less than VkBuildPartitionedAccelerationStructureInfoNV::`input`::`partitionCount`

- VUID-VkPartitionedAccelerationStructureWriteInstanceDataNV-explicitAABB-10570
  `explicitAABB` must be a valid bounding box if instance was created with flag `VK_PARTITIONED_ACCELERATION_STRUCTURE_INSTANCE_FLAG_ENABLE_EXPLICIT_BOUNDING_BOX_NV` set

Valid Usage (Implicit)

- VUID-VkPartitionedAccelerationStructureWriteInstanceDataNV-instanceFlags-parameter
  `instanceFlags` must be a valid combination of VkPartitionedAccelerationStructureInstanceFlagBitsNV values

## See Also

VK_NV_partitioned_acceleration_structure, VkDeviceAddress, VkPartitionedAccelerationStructureInstanceFlagsNV, VkTransformMatrixKHR

## 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