Elements, slices & chains

OmnaDMX keeps where the LEDs physically are separate from what plays on them. Get this model and you can run many patterns from one controller; miss it and you’re stuck with one.

The three layers

A strip is one physical data output: a pixel count and a colour order.

A slice is a contiguous span of a strip, say pixels 0–59. A strip holds 1 to 32 slices. The slice is the unit you assign and address.

An element is a virtual lighting unit that owns a pattern — its pattern, its motion, and in DMX modes its place in the patch. An element aggregates one or more slices. It can span several strips, and one strip can carry slices from different elements. The device allows 8 elements.

Strips and elements both take names. Rename a strip inline in its header and an element in its detail panel; the name then follows it everywhere — the pickers across the web app and the OLED — so you’re assigning bar front, not element 3.

A worked example

Take a 180-pixel strip on output 1 and cut it into three 60-pixel slices, each on its own element. Now one physical strip runs three independent patterns: blue breathing on pixels 0–59, a warm chase on 60–119, static amber on 120–179. Re-slice or re-assign whenever you like. Nothing is soldered to a pattern.

Standalone vs linked (chains)

A slice is either standalone or part of a chain.

A standalone slice (the default) renders the whole pattern on its own, scaled to its own length. Independent slices each get the complete pattern.

A linked chain joins two or more slices end-to-end into one longer virtual strip. The pattern flows across all members in order, as if they were a single run.

Use standalone when each slice should be its own complete pattern — matching uplights, for instance. Use a chain when one effect should travel across separate physical segments, like a sweep crossing four short strips as one.

Chain rule

An explicit chain always has at least two members. Drop a chain to one member and it reverts to a standalone slice; the firmware enforces this when the config loads, so a “chain of one” can’t happen.

Where you set this up

The Slices / Elements area is where you create and resize slices on each strip, assign them to elements, drag slice chips together to build or extend chains, and reorder chain members. The strip map mirrors the physical-to-virtual layout, so you can trace which pixels belong to which element and chain.

Why ordering matters for DMX

In DMX Pixels mode the order of elements, slices, and chains is the desk patch order. Pixels stream in a fixed sequence (element, then its slot order, then chain, then position in chain, then strip, slice, pixel), and an explicit chain takes a contiguous channel range. So chaining is also how you keep a logical element on one unbroken block of channels. Reorder in the Elements area and the patch re-derives; the app shows the resulting channel ranges so you can match the desk. The full mechanics are in Multi-universe addressing.

Next: Operating modes.