# VkMicromapBuildSizesInfoEXT(3) Manual Page

## Name

VkMicromapBuildSizesInfoEXT - Structure specifying build sizes for a micromap

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## C Specification

The `VkMicromapBuildSizesInfoEXT` structure describes the required build sizes for a micromap and scratch buffers and is defined as:

    // Provided by VK_EXT_opacity_micromap
    typedef struct VkMicromapBuildSizesInfoEXT {
        VkStructureType    sType;
        const void*        pNext;
        VkDeviceSize       micromapSize;
        VkDeviceSize       buildScratchSize;
        VkBool32           discardable;
    } VkMicromapBuildSizesInfoEXT;

## Members

- `sType` is a VkStructureType value identifying this structure.

- `pNext` is `NULL` or a pointer to a structure extending this structure.

- `micromapSize` is the size in bytes required in a VkMicromapEXT for a build or update operation.

- `buildScratchSize` is the size in bytes required in a scratch buffer for a build operation.

- `discardable` indicates whether or not the micromap object may be destroyed after an acceleration structure build or update. A false value means that acceleration structures built with this micromap may contain references to the data contained therein, and the application must not destroy the micromap until ray traversal has concluded. A true value means that the information in the micromap will be copied by value into the acceleration structure, and the micromap may be destroyed after the acceleration structure build concludes.

## Description

Valid Usage (Implicit)

- VUID-VkMicromapBuildSizesInfoEXT-sType-sType
  `sType` must be `VK_STRUCTURE_TYPE_MICROMAP_BUILD_SIZES_INFO_EXT`

- VUID-VkMicromapBuildSizesInfoEXT-pNext-pNext
  `pNext` must be `NULL`

## See Also

VK_EXT_opacity_micromap, VkBool32, VkDeviceSize, VkStructureType, vkGetMicromapBuildSizesEXT

## 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