C Specification

To query acceleration structure size parameters call:

// Provided by VK_KHR_acceleration_structure
void vkCmdWriteAccelerationStructuresPropertiesKHR(
    VkCommandBuffer                             commandBuffer,
    uint32_t                                    accelerationStructureCount,
    const VkAccelerationStructureKHR*           pAccelerationStructures,
    VkQueryType                                 queryType,
    VkQueryPool                                 queryPool,
    uint32_t                                    firstQuery);


  • commandBuffer is the command buffer into which the command will be recorded.

  • accelerationStructureCount is the count of acceleration structures for which to query the property.

  • pAccelerationStructures is a pointer to an array of existing previously built acceleration structures.

  • queryType is a VkQueryType value specifying the type of queries managed by the pool.

  • queryPool is the query pool that will manage the results of the query.

  • firstQuery is the first query index within the query pool that will contain the accelerationStructureCount number of results.


Accesses to any of the acceleration structures listed in pAccelerationStructures must be synchronized with the VK_PIPELINE_STAGE_2_ACCELERATION_STRUCTURE_COPY_BIT_KHR pipeline stage or the VK_PIPELINE_STAGE_ACCELERATION_STRUCTURE_BUILD_BIT_KHR pipeline stage, and an access type of VK_ACCESS_ACCELERATION_STRUCTURE_READ_BIT_KHR.

  • If queryType is VK_QUERY_TYPE_ACCELERATION_STRUCTURE_COMPACTED_SIZE_KHR, then the value written out is the number of bytes required by a compacted acceleration structure.

  • If queryType is VK_QUERY_TYPE_ACCELERATION_STRUCTURE_SERIALIZATION_SIZE_KHR, then the value written out is the number of bytes required by a serialized acceleration structure.

Valid Usage
  • VUID-vkCmdWriteAccelerationStructuresPropertiesKHR-accelerationStructure-08924
    The VkPhysicalDeviceAccelerationStructureFeaturesKHR::accelerationStructure feature must be enabled

  • VUID-vkCmdWriteAccelerationStructuresPropertiesKHR-queryPool-02493
    queryPool must have been created with a queryType matching queryType

  • VUID-vkCmdWriteAccelerationStructuresPropertiesKHR-queryPool-02494
    The queries identified by queryPool and firstQuery must be unavailable

  • VUID-vkCmdWriteAccelerationStructuresPropertiesKHR-buffer-03736
    The buffer used to create each acceleration structure in pAccelerationStructures must be bound to device memory

  • VUID-vkCmdWriteAccelerationStructuresPropertiesKHR-query-04880
    The sum of query plus accelerationStructureCount must be less than or equal to the number of queries in queryPool

  • VUID-vkCmdWriteAccelerationStructuresPropertiesKHR-pAccelerationStructures-04964
    All acceleration structures in pAccelerationStructures must have been built prior to the execution of this command

  • VUID-vkCmdWriteAccelerationStructuresPropertiesKHR-accelerationStructures-03431
    All acceleration structures in pAccelerationStructures must have been built with VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_COMPACTION_BIT_KHR if queryType is VK_QUERY_TYPE_ACCELERATION_STRUCTURE_COMPACTED_SIZE_KHR

  • VUID-vkCmdWriteAccelerationStructuresPropertiesKHR-queryType-06742

Valid Usage (Implicit)
  • VUID-vkCmdWriteAccelerationStructuresPropertiesKHR-commandBuffer-parameter
    commandBuffer must be a valid VkCommandBuffer handle

  • VUID-vkCmdWriteAccelerationStructuresPropertiesKHR-pAccelerationStructures-parameter
    pAccelerationStructures must be a valid pointer to an array of accelerationStructureCount valid VkAccelerationStructureKHR handles

  • VUID-vkCmdWriteAccelerationStructuresPropertiesKHR-queryType-parameter
    queryType must be a valid VkQueryType value

  • VUID-vkCmdWriteAccelerationStructuresPropertiesKHR-queryPool-parameter
    queryPool must be a valid VkQueryPool handle

  • VUID-vkCmdWriteAccelerationStructuresPropertiesKHR-commandBuffer-recording
    commandBuffer must be in the recording state

  • VUID-vkCmdWriteAccelerationStructuresPropertiesKHR-commandBuffer-cmdpool
    The VkCommandPool that commandBuffer was allocated from must support compute operations

  • VUID-vkCmdWriteAccelerationStructuresPropertiesKHR-renderpass
    This command must only be called outside of a render pass instance

  • VUID-vkCmdWriteAccelerationStructuresPropertiesKHR-videocoding
    This command must only be called outside of a video coding scope

  • VUID-vkCmdWriteAccelerationStructuresPropertiesKHR-accelerationStructureCount-arraylength
    accelerationStructureCount must be greater than 0

  • VUID-vkCmdWriteAccelerationStructuresPropertiesKHR-commonparent
    Each of commandBuffer, queryPool, and the elements of pAccelerationStructures must have been created, allocated, or retrieved from the same VkDevice

Host Synchronization
  • Host access to commandBuffer must be externally synchronized

  • Host access to the VkCommandPool that commandBuffer was allocated from must be externally synchronized

Command Properties
Command Buffer Levels Render Pass Scope Video Coding Scope Supported Queue Types Command Type






See Also

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 2014-2023 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0