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GDTF Fixtures

phix uses the General Device Type Format (GDTF) as its fixture format. GDTF is an industry-standard open format created by MA Lighting, Robe, and Vectorworks. It describes everything about a DMX fixture: its attributes, DMX modes, geometry, and more.

What is a GDTF file?#

A GDTF file (.gdtf) contains:

  • Fixture metadata — manufacturer, model name, fixture type
  • DMX modes — different channel configurations for the fixture (e.g., "Basic (10ch)", "Extended (20ch)")
  • Attributes — what the fixture can do: dimmer, pan, tilt, color, gobo, zoom, etc.
  • Geometry — physical structure, including sub-fixtures for multi-cell LED bars

When you import a GDTF file, phix registers the fixture type and makes it available for patching.

DMX modes#

Most fixtures have multiple DMX modes. A simpler mode uses fewer channels and is easier to manage; a full mode exposes all features. When patching a fixture you choose which mode to use.

Example — a moving head might have:

  • Basic (14ch) — dimmer, pan, tilt, color, gobo
  • Extended (28ch) — all of the above plus fine pan/tilt, prism, frost, strobe
tip

If you're unsure which mode to use, start with the extended or full mode. You can always change it later (you'll need to repatch at a new address if the channel count changes).

Sub-fixtures#

Some fixtures — particularly LED bars and pixel arrays — contain multiple independently controlled sections called sub-fixtures. phix supports sub-fixtures fully.

When you patch an LED bar with 10 pixels, phix creates:

  • A parent fixture (e.g., fixture 101) representing the whole bar
  • Sub-fixtures (e.g., 101.1 through 101.10) for each individual pixel

You can select and control sub-fixtures independently using dot notation:

fixture 101.1 thru 101.5   -- select pixels 1-5fixture 101.0              -- select all sub-fixtures (no parent body)

Where to get GDTF files#

GDTF Share (online library)#

GDTF Share is the official online repository with thousands of fixture profiles. phix can search and download from it directly:

gdtf search "Robe Spiider"gdtf download <rid>

You need a free GDTF Share account. Set your credentials with:

config gdtf-share <username> <password>

Manufacturer websites#

Many manufacturers publish GDTF files on their websites. Download the .gdtf file and import it:

gdtf import /path/to/FixtureName.gdtf

Local library folder#

phix can scan a folder for GDTF files and import them all at once:

config gdtf-path /path/to/your/gdtf/librarygdtf scan

All .gdtf files in that folder are imported into the current show.

Managing imported fixture types#

List all fixture types currently loaded in your show:

list gdtf

Fixture types are stored per-show. If you open a different show file that references the same fixture types, phix looks for them in your library folder automatically.