Chain Conveyors

A Chain provides continuous transport using identical elements: chain links, buckets, carriers, pallet fixtures or hooks. All follow the same curve and move with one drive. Use it to model a chain conveyor, bucket elevator or overhead power-and-free line. Configure the curve, carrier and carrier count instead of adding one component per carrier.

The curve and carriers are prepared as follows:

• The curve is authored in Unity and baked into the file. It arrives as a table of positions and orientations sampled at equal distances along the curve. The viewer follows the curve Unity produced rather than recomputing it. There is no curve editing in the browser.
• The carriers are built on load, not stored. The document carries one element as a template. On load the viewer clones it as many times as configured and places each clone along the curve. If the exported file includes a preview row of elements, the generated carriers replace them rather than creating a second set.

A Chain differs from an energy chain (cable carrier), which deforms a single moulded part along a path instead of repeating one.

Key properties

Set on the chain node:

Property	Description
Connected Drive	The drive that moves the whole chain. Without a resolvable drive the elements are placed at their start positions and stay there.
Chain Element	The node used as the template for every carrier. Without it the chain does nothing at all.
Number Of Elements	How many carriers are built from the template. Zero builds none.
Name Chain Element	Base name for the generated carriers. Left empty, the template’s own name is used.
Start Position	Where the first carrier sits along the chain, in millimetres.
Calculated Delta Position	On (the default), the spacing is the chain length divided by the number of elements. Adding a carrier redistributes them all. Off, Delta Position is used instead.
Delta Position	Manual spacing between two carriers in millimetres. Ignored while Calculated Delta Position is on.
Chain Orientation	Horizontal or Vertical. Vertical flips the carriers’ up direction, which is what a bucket elevator needs at the turnarounds.
Scaled On Fixed Length / Fixed Length	Scale motion over a stated length rather than the curve’s real arc length. Use this to match a drive whose travel was defined against a nominal chain length.

Set on the element template:

Property	Description
Align With Chain	On, each carrier turns to follow the curve. Off, only its position is written and it keeps the template’s orientation, for example a bucket that must stay upright.
Offset To Drive Position	Shifts every carrier along the chain relative to the drive position, in millimetres. Use it to line the carriers up with a station without moving the drive’s zero.
Initial Position	Where this element sits along the chain in millimetres. The chain sets it for the carriers it generates.

Quick Start

1. Build the chain in Unity with the Chain and ChainElement components: a spline for the curve, one element as the template, and a drive.
2. Export the model to GLB.
3. Open the document in realvirtual. The carriers are built and placed on load.
4. Run the drive. All carriers move together; passing the end of a closed curve continues at its start.
5. To change the number of carriers or their spacing, change it in Unity and export again. The count and the curve come from the file.

When a chain does not move

What you see	What it means
Carriers stand at their start positions	The drive named by the chain could not be resolved. Everything else is fine.
No carriers at all	The element template could not be resolved, or the number of elements is zero.
The chain is inert and the console says so	The curve is missing from the file or has too few samples to follow. Re-export from Unity.

See also

• Documents — the GLB that carries the chain and its curve
• Rigid-body mechanisms — drives, jerk-limited motion and travel limits
• Open Digital Twin Format — the Chain and ChainElement field reference