> ## Documentation Index
> Fetch the complete documentation index at: https://support.lumafield.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Stack Aggregation

> Inspect a slab of slices as a single 2D view

Stack Aggregation combines a contiguous range of slices — a slab — into a single 2D view. Instead of scrubbing one slice at a time, you see a thickness of data at once, which makes internal features and boundaries easier to locate.

Use Stack Aggregation when you want context through the volume: finding a defect that spans several slices, lining up a feature before you lock an [Inspection Plane](/voyager/voyager-inspection-planes), or reviewing a region before you [promote it to full resolution](/voyager/voyager-data-objects-and-workflows#promote-slice).

<Tip>
  When you are cropping an [ROI](/voyager/voyager-region-of-interest#5-cropping), **Deep Slice in 2D** is the same idea applied to the crop workflow: each cardinal axis collapses into one 2D image so you can set bounds without scrubbing.
</Tip>

<h2 id="working-with-a-slab">
  Working with a slab
</h2>

Open a Reconstruction or ROI, choose a cardinal 2D view, and expand the view from a single slice into a slab. The Viewport shows the aggregated stack, and you can keep adjusting the slab as you inspect.

<video controls className="w-full aspect-video" src="https://mintcdn.com/lumafield/ZWRoFQpofIViz7Vs/images/stack_aggregation.mp4?fit=max&auto=format&n=ZWRoFQpofIViz7Vs&q=85&s=4e307eed88c72b686dec8f7eecba5be5" data-path="images/stack_aggregation.mp4" />

*Expanding a single slice into a slab and adjusting the aggregated view.*

A slab setup is bookmarkable. Saving a [Bookmark](/voyager/voyager-bookmarks) stores the slab the same way it stores any other view, so teammates can reopen the same aggregated view.

<h2 id="inspection-planes-and-promotion">
  Inspection Planes and full-resolution promotion
</h2>

You can create an [Inspection Plane](/voyager/voyager-inspection-planes) from a slab and take 2D measurements on that locked view.

You can also [promote a slab to full resolution](/voyager/voyager-data-objects-and-workflows#promote-slice), the same way you promote a single cardinal slice. Use this when the aggregated view shows a region you want as a high-resolution image for download, Bookmarking, or further review.

<h2 id="unroll">
  Unroll, when the part is a cylinder
</h2>

Stack Aggregation looks through a thickness of the volume and leaves that thickness in place. [Unroll](/voyager/voyager-unroll) is the companion for a tube, bore, or thread: it cuts a ring around a cylinder axis and lays the wall flat so the whole circumference is one image. Probe or profile a slab with the [2D inspection tools](/voyager/voyager-2d-inspection) when you want a reading without unwrapping.


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