> ## 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.

# Manual Feature Authoring

> Create, refine, and delete plane and cylinder features by hand in Dimensioning Mode

Manual Feature Authoring gives you control over the features you measure to and from. In [Dimensioning Mode](/voyager/voyager-modes#dimensioning-mode), the **Features** toolbar button lets you author planes and cylinders by hand to complement [automatically extracted](/voyager/voyager-feature-extraction) features.

Authored features behave exactly like automatic ones — selectable, measurable, and usable as [datums](/voyager/voyager-datums). They do not add new GD\&T types. You are still working with plane and cylinder primitives that [Direct Dimensions](/voyager/voyager-direct-dimensions), [Flatness](/voyager/voyager-flatness), [Cylindricity](/voyager/voyager-cylindricity), Datums, and [Profile](/voyager/voyager-profile) already consume.

<h2 id="requirements">
  Requirements
</h2>

Manual Feature Authoring needs a Feature Set extracted with **algorithm v20 or newer**. See [Feature Extraction](/voyager/voyager-feature-extraction#algorithm-v20).

On older extractions, the authoring controls are greyed out and a tooltip explains why. Re-run Feature Extraction on the parent reconstruction to replace that Feature Set with a v20 (or newer) run, then author features on the result.

<h2 id="when-to-use">
  When to use Manual Feature Authoring
</h2>

Use authoring to complement automatic extraction — not to replace it. Typical cases:

* **Thin rims** that automatic extraction under-represents
* **Multiple disconnected components** that should belong to one plane
* **Small patches** that mimic CMM probe points
* **Small pins and threaded holes** that need a cylinder sized to the real geometry
* **Cleanup** — delete features you do not want in the scene so measurement and datum work stay focused

<h2 id="create-planes">
  Create planes
</h2>

Create planes large and small on **contiguous and non-contiguous** surfaces. Non-contiguous patches can still define a single plane, which is how thin rims and disconnected faces become measurable.

<video controls className="w-full aspect-video" src="https://mintlify.s3.us-west-1.amazonaws.com/lumafield/images/mfa_plane.mp4" />

*Authoring a plane on a rim of a part.*

<Steps>
  <Step title="Open Features">
    In Dimensioning Mode, choose **Features** in the Toolbar. Confirm the Feature Set is algorithm v20 or newer.
  </Step>

  <Step title="Create a plane">
    Author a plane on the surfaces that should define it. Include disconnected patches when they belong to the same geometric plane.
  </Step>

  <Step title="Review membership">
    Confirm the highlighted surface is the plane you intend to measure or datum from.
  </Step>
</Steps>

<h2 id="create-cylinders">
  Create cylinders
</h2>

Create cylinders large and small, including small pins and threaded holes.

<video controls className="w-full aspect-video" src="https://mintlify.s3.us-west-1.amazonaws.com/lumafield/images/mfa_cylinder.mp4" />

*Authoring a cylinder on geometry that had uneven edges in automatic feature extraction.*

<Steps>
  <Step title="Open Features">
    Choose **Features** in the Toolbar.
  </Step>

  <Step title="Create a cylinder">
    Author a cylinder on the pin, hole, or thread you need to measure. Size it to the region that should participate in Diameter, Cylindricity, or an Axis datum.
  </Step>

  <Step title="Review membership">
    Confirm the cylinder captures the intended surface and not neighboring geometry.
  </Step>
</Steps>

<h2 id="refine-automatic-features">
  Refine automatic features
</h2>

Right-click any automatic feature to adjust it directly. Refinement uses the same membership tools as a feature you created from scratch.

<h2 id="paint-erase-erode">
  Paint, erase, and erode
</h2>

Paint, erase, and erode give full manual control over **which surface belongs to the feature**:

* **Paint** — add surface to the feature
* **Erase** — remove surface from the feature
* **Erode** — shrink membership inward to drop noisy edges or over-extracted boundary

Use these tools after create or after right-click refine until the feature matches the geometry you will measure.

<h2 id="delete-features">
  Delete features
</h2>

Delete features to clean up the scene and focus on just what you want. Deleted automatic or authored features are removed from the Feature Set for that reconstruction; remaining features stay available to every child ROI.

<h2 id="measure-and-datum">
  Measure and datum from authored features
</h2>

Once a feature is in the Feature Set, use it like any other primitive:

* [Distance, Angle, and Diameter](/voyager/voyager-direct-dimensions)
* [Flatness](/voyager/voyager-flatness) on planes
* [Cylindricity](/voyager/voyager-cylindricity) on cylinders
* [Datums](/voyager/voyager-datums) (Plane, Axis, Midplane)

<h2 id="related-pages">
  Related pages
</h2>

* [Feature Extraction](/voyager/voyager-feature-extraction)
* [3D Auto-Dimensioning](/voyager/voyager-auto-dimensioning)
* [Direct Dimensions](/voyager/voyager-direct-dimensions)
* [Flatness](/voyager/voyager-flatness)
* [Cylindricity](/voyager/voyager-cylindricity)
* [Datum Definition](/voyager/voyager-datums)
* [Profile](/voyager/voyager-profile)
* [Voyager Modes](/voyager/voyager-modes)
* [Voyager Release Notes](/platform/voyager-release-notes) and [Monthly Highlights](/platform/monthly-highlights)