Adding Fixtures

Overview

Fixtures are the core building blocks of any QLC+ project. A fixture represents a physical lighting device controlled via DMX, with specific channels for controlling various parameters like intensity, color, position, and effects.

Understanding Fixtures

In QLC+, each fixture instance has:

Fixture ID: A unique identifier assigned to the fixture in your project
Name: A friendly name to identify the fixture (e.g., “Front Wash 1”)
Universe: The DMX universe the fixture belongs to (zero-based: 0-7)
Address: The starting DMX address (zero-based: 0-511)
Channels: The number of DMX channels the fixture occupies
Type: The fixture category (Moving Head, Dimmer, Scanner, LED Bar, etc.)

QLC+ uses zero-based addressing internally. Universe 1 is stored as 0, and DMX address 1 is stored as 0. The UI automatically converts these for user-friendly display.

Adding a Fixture

Open Fixture Manager

Navigate to the Fixture Manager in the QLC+ interface. This is where you’ll add and manage all fixtures in your project.

Select Fixture Definition

Choose a fixture definition from the built-in library:

Browse by manufacturer and model
Select the appropriate fixture mode based on your device’s channel configuration
Each mode represents a different channel layout for the same fixture

Configure Addressing

Set the fixture’s DMX parameters:

// Internal representation (from fixture.cpp:125-137)
void Fixture::setUniverse(quint32 universe)
{
    // Universe stored in highest 7 bits
    m_address = (m_address & 0x01FF) | (universe << 9);
}

void Fixture::setAddress(quint32 address)
{
    // Don't allow more than 512 channels per universe
    if (address > 511)
        return;
    // Address stored in lowest 9 bits
    m_address = (m_address & 0xFE00) | (address & 0x01FF);
}

Universe: Select which DMX universe (typically 1-4 for most setups)
Address: Choose the starting DMX channel
Ensure there’s no address overlap with other fixtures

Name the Fixture

Give your fixture a descriptive name that helps you identify it during programming (e.g., “Stage Left Par”, “Moving Head 3”).

Add to Project

Confirm the fixture addition. The fixture will now appear in your fixture list and be available for use in scenes and functions.

Fixture Types

QLC+ supports various fixture types defined in qlcfixturedef.h:93-109:

Available Fixture Types

ColorChanger: RGB/RGBW color mixing fixtures
Dimmer: Simple dimmer channels or packs
Effect: Special effect devices
Fan: Fans for fog/haze effects
Flower: Flower-style LED effects
Hazer: Haze machines
Laser: Laser effect projectors
LEDBarBeams: LED bars with individual beam control
LEDBarPixels: LED bars with pixel-level control
MovingHead: Moving head fixtures with pan/tilt
Scanner: Mirror scanner fixtures
Smoke: Smoke machines
Strobe: Strobe lights
Other: Miscellaneous fixture types

Generic Dimmers

If your fixture doesn’t have a definition in the library, you can create a generic dimmer:

// From fixture.cpp:180-201
void Fixture::setChannels(quint32 channels)
{
    if (m_fixtureDef == NULL && m_fixtureMode == NULL)
    {
        QLCFixtureDef *fixtureDef = genericDimmerDef(channels);
        QLCFixtureMode *fixtureMode = genericDimmerMode(fixtureDef, channels);
        setFixtureDefinition(fixtureDef, fixtureMode);
    }
    m_channels = channels;
}

Select Generic Dimmer

Choose “Generic” as the manufacturer and “Generic Dimmer” as the model.

Set Channel Count

Specify how many consecutive dimmer channels you need (1-512).

Configure Addressing

Set the universe and starting address as with regular fixtures.

Cross-Universe Fixtures

Some large fixtures may span across universe boundaries:

// From fixture.h:185-195
void setCrossUniverse(bool enable);
bool crossUniverse() const;

When a fixture’s channels extend beyond the 512-channel limit of a single universe, enable the cross-universe option. The fixture’s channels will automatically continue into the next universe.

Cross-universe fixtures require careful planning. Ensure your DMX output devices support multi-universe output and that addresses are properly configured.

Fixture Modes

Most intelligent fixtures support multiple operating modes with different channel configurations:

Basic Mode: Fewer channels, simplified control
Standard Mode: Full feature set with moderate channel count
Extended Mode: Maximum features, highest channel count

Example: Fixture Mode Structure

From the ADB ALC4 fixture definition:

<Mode Name="Standard 5 Channels (CT 7 Preset)">
  <Channel Number="0">Master Dimmer</Channel>
  <Channel Number="1">CT Preset</Channel>
  <Channel Number="2">Red</Channel>
  <Channel Number="3">Green</Channel>
  <Channel Number="4">Blue</Channel>
</Mode>

<Mode Name="Extended 21 Channels (CT 7 Preset)">
  <Channel Number="0">Master Dimmer</Channel>
  <Channel Number="1">Dimmer 1</Channel>
  <!-- 19 more channels... -->
</Mode>

Choose the mode that matches your fixture’s DIP switch or menu settings. Using the wrong mode will result in incorrect channel mapping.

Managing Fixture Properties

Changing Fixture Address

You can modify a fixture’s address after creation:

Select the fixture in the Fixture Manager
Edit the universe or address fields
Verify no conflicts with other fixtures
Apply the changes

Renaming Fixtures

Give fixtures meaningful names:

// From fixture.h:135-147
void setName(const QString& name);
QString name() const;

Good naming conventions:

Location-based: “Stage Left Par 1”, “Truss Front MH 3”
Function-based: “Backlight Wash”, “Audience Color”
Zone-based: “Zone A Dimmer 1”, “Zone B Spot 2”

Removing Fixtures

When removing a fixture:

Ensure it’s not used in any active scenes or chasers
Select the fixture in the Fixture Manager
Delete the fixture
The fixture ID is freed for reuse

Removing a fixture that’s referenced in functions will cause those functions to malfunction. QLC+ will warn you about these dependencies.

Fixture Channels

Each fixture has channels for controlling different parameters:

Channel Properties

// From fixture.h:226-289
quint32 channels() const;  // Total number of channels
const QLCChannel* channel(quint32 channel) const;  // Get specific channel
quint32 channelAddress(quint32 channel) const;  // Get DMX address of channel

Channel Groups

Channels are organized by function:

Intensity: Dimmer/master intensity channels
Colour: RGB, CMY, color wheel channels
Gobo: Gobo wheel selection and rotation
Shutter: Shutter/strobe channels
Speed: Speed control for effects
Prism: Prism insertion and rotation
Beam: Focus, zoom, iris control
Pan: Horizontal movement
Tilt: Vertical movement

Finding Specific Channels

// Get RGB channels (from fixture.h:286-290)
QVector<quint32> rgbChannels(int head = 0) const;
QVector<quint32> cmyChannels(int head = 0) const;

// Find channel by group and color
quint32 channel(QLCChannel::Group group,
                QLCChannel::PrimaryColour color = QLCChannel::NoColour) const;

Multi-Head Fixtures

Fixtures with multiple heads (like LED bars) have special considerations:

// From fixture.h:415-433
int heads() const;  // Number of heads
QLCFixtureHead head(int index) const;  // Get specific head

Each head in a multi-head fixture:

Has its own set of channels
Can be controlled independently
Is represented in fixture groups as separate entities

Example: Multi-Head Configuration

From the ADB ALC4 fixture (Matrix mode with 4 heads):

<Mode Name="Matrix 20 Channels (CT 7 Preset)">
  <Head>
    <Channel>4</Channel>  <!-- Blue 1 -->
    <Channel>2</Channel>  <!-- Red 1 -->
    <Channel>3</Channel>  <!-- Green 1 -->
    <Channel>0</Channel>  <!-- Dimmer 1 -->
    <Channel>1</Channel>  <!-- CT Preset 1 -->
  </Head>
  <Head>
    <Channel>9</Channel>  <!-- Blue 2 -->
    <Channel>6</Channel>  <!-- Red 2 -->
    <!-- ... -->
  </Head>
  <!-- 2 more heads... -->
</Mode>

Best Practices

Address Planning

Document your DMX address plan before adding fixtures
Leave gaps between fixtures for future expansion
Group similar fixtures in consecutive address ranges
Use a spreadsheet to track universe and address assignments

Naming Conventions

Use consistent naming patterns across your project
Include fixture type and number in the name
Consider adding location information
Keep names concise but descriptive

Mode Selection

Match the mode to your fixture’s physical configuration
Consider channel count vs. feature requirements
Document which mode you’re using for each fixture
Test the fixture after adding to verify correct operation

Next Steps

Learn about Fixture Groups for controlling multiple fixtures together
Explore Channel Modifiers to adjust channel behavior
Create custom definitions with the Fixture Editor

Get Started

Core Concepts

Functions

Fixture Management

Virtual Console

Input/Output

Advanced Features

Adding Fixtures

Overview

Understanding Fixtures

Adding a Fixture

Fixture Types

Generic Dimmers

Cross-Universe Fixtures

Fixture Modes

Example: Fixture Mode Structure

Managing Fixture Properties

Changing Fixture Address

Renaming Fixtures

Removing Fixtures

Fixture Channels

Channel Properties

Channel Groups

Finding Specific Channels

Multi-Head Fixtures

Example: Multi-Head Configuration

Best Practices

Next Steps

Build docs developers (and LLMs) love

Get Started

Core Concepts

Functions

Fixture Management

Virtual Console

Input/Output

Advanced Features

​Overview

​Understanding Fixtures

​Adding a Fixture

​Fixture Types

​Generic Dimmers

​Cross-Universe Fixtures

​Fixture Modes

​Example: Fixture Mode Structure

​Managing Fixture Properties

​Changing Fixture Address

​Renaming Fixtures

​Removing Fixtures

​Fixture Channels

​Channel Properties

​Channel Groups

​Finding Specific Channels

​Multi-Head Fixtures

​Example: Multi-Head Configuration

​Best Practices

​Next Steps

Build docs developers (and LLMs) love

Overview

Understanding Fixtures

Adding a Fixture

Fixture Types

Generic Dimmers

Cross-Universe Fixtures

Fixture Modes

Example: Fixture Mode Structure

Managing Fixture Properties

Changing Fixture Address

Renaming Fixtures

Removing Fixtures

Fixture Channels

Channel Properties

Channel Groups

Finding Specific Channels

Multi-Head Fixtures

Example: Multi-Head Configuration

Best Practices

Next Steps