API Reference — `dna/layers/DescriptorWriter`

`class DNAAPI DescriptorWriter : public HeaderWriter`

Write metadata about the character and the rig: name, archetype, gender, age, key-value metadata, coordinate conventions, LOD count and database info.

When to use this

Use it when you author a DNA and need to set its descriptor. Implementors should inherit from Writer itself, not from this class.

Method groups

Group	Methods
Character	setName, setArchetype, setGender, setAge
MetaData	clearMetaData, setMetaData
Conventions	setTranslationUnit, setRotationUnit, setCoordinateSystem, setRotationSequence, setRotationSign, setFaceWindingOrder
LOD	setLODCount, setDBMaxLOD
DB	setDBComplexity, setDBName

Example

// Obtain a writer from BinaryStreamWriter or equivalent Writer subclass.
// DescriptorWriter* dw = writer->getDescriptorWriter();

dw->setName("Ada");
dw->setArchetype(Archetype::other);
dw->setGender(Gender::female);
dw->setAge(30);

// Coordinate frame: Y-up, centimetre, XYZ rotation order.
dw->setTranslationUnit(TranslationUnit::cm);
dw->setCoordinateSystem(CoordinateSystem::RightHand_YUp);
dw->setRotationUnit(RotationUnit::degrees);
dw->setRotationSequence(RotationSequence::XYZ);

// Six LOD levels: 0 (highest detail) ... 5 (lowest).
dw->setLODCount(6);
dw->setDBMaxLOD(5);

// Optional key-value metadata; overwrite or delete by key.
dw->setMetaData("rig_version", "2.4.1");
dw->setMetaData("obsolete_key", nullptr);  // deletes the entry

dw->setDBComplexity("Face");
dw->setDBName("MetaHumans");

Parameters

Name	Type	Description
`name` (setName)	`const char*`	required — null-terminated character name; the string is copied (allocation occurs).
`archetype`	`Archetype`	required — enum value describing the character archetype.
`gender`	`Gender`	required — enum value describing the character gender.
`age`	`std::uint16_t`	required — character age in years.
`key` (setMetaData)	`const char*`	required — unique null-terminated key; duplicate calls overwrite the previous value.
`value` (setMetaData)	`const char*`	required — null-terminated metadata value; pass `nullptr` to delete the key.
`unit` (setTranslationUnit)	`TranslationUnit`	required — spatial unit for translation values (e.g., centimetres, metres).
`unit` (setRotationUnit)	`RotationUnit`	required — angular unit for rotation values (e.g., degrees, radians).
`system`	`CoordinateSystem`	required — handedness and up-axis convention for the rig.
`rotationSequence`	`RotationSequence`	required — Euler rotation application order (e.g., XYZ).
`rotationSign`	`const RotationSign&`	required — sign convention for rotation axes.
`faceWindingOrder`	`FaceWindingOrder`	required — vertex winding order for face geometry.
`lodCount` (setLODCount)	`std::uint16_t`	required — total number of LOD levels; level 0 is highest detail.
`lod` (setDBMaxLOD)	`std::uint16_t`	required — maximum LOD index stored in the DNA data for this character.
`name` (setDBComplexity)	`const char*`	required — null-terminated name of the input control interface; string is copied.
`name` (setDBName)	`const char*`	required — null-terminated name of the originating database; string is copied.

Watch out for

Consecutive setMetaData calls with the same key overwrite existing data.
Passing nullptr as the value removes the key.
Strings are copied, which costs an additional allocation.
Do not subclass DescriptorWriter directly — the class docstring states that implementors must inherit from Writer itself. Subclassing DescriptorWriter bypasses the full writer contract.
Passing nullptr as the value argument to setMetaData deletes the associated key rather than storing a null value. This is a deletion shortcut, not a no-op.
Every const char* name or value is copied internally, so the caller's buffer may be freed after the call — but each copy involves an allocation; avoid calling string setters in tight per-frame loops.

API Reference — dna/layers/DescriptorWriter

class DNAAPI DescriptorWriter : public HeaderWriter