A trihedron billboard is made up of vertical triangular slats or prisms that turn together, showing one of three images at a time. As the slats rotate, the face changes from one message to the next, giving three advertisers or three campaign creatives a share of the same position.
Because it moves, a trihedron draws the eye more than a fixed face does. It also brings a mechanical element to the structure, so it needs a different approach to design, power and servicing than a static unipole.
Typical specifications
- Facevertical triangular louvres, three images per face
- Mechanismmotor and drive turning all louvres together at set intervals
- Face formatsfor example 6 m x 3 m or 12 m x 3 m, subject to site and approval
- Supportsingle column or frame, engineered for the face and mechanism
- Powergrid or solar supply sized to the drive
- Printed stripsfitted to the louvres in sequence by trained flighting crews
- Servicingaccess arranged for the drive, bearings and louvres
How a trihedron works
The face is built from many narrow triangular louvres mounted side by side in a frame. Each louvre has three sides, and each side carries a strip of the printed image. A motor and drive mechanism turn all the louvres together at set intervals, so the full picture on the first side gives way to the second and then the third.
The three images are printed in strips and fitted to the louvres in sequence, which makes accurate artwork preparation and careful flighting essential. A strip out of order or out of alignment breaks the picture.
Where trihedrons perform
They work best where traffic moves at moderate speed or queues, and where viewers have time to see more than one rotation: shopping-centre approaches, city arterials, entrances to business districts and busy intersections in places like Sandton, Rosebank, Durban and Cape Town.
On a fast freeway, where a driver passes the face in a few seconds, a fixed highway billboard is often the better choice. For a site where several brands share a position or a campaign needs a sequence of messages, the trihedron is a strong format. See also tri-vision billboards for the closely related format.
Structure, power and servicing
The support can be a single column or a heavier frame, depending on the face size. The mechanism needs an electrical supply, either from the grid or from a solar installation designed for the load, and the motor and drive should be reached easily for servicing.
We plan walkways and access with the mechanism in mind, and our maintenance team inspects the drive, the bearings and the louvres as part of a service plan agreed with you. Moving parts wear, and a trihedron that is left unserviced will eventually stop turning or lose its alignment.
Rotation, content and approvals
The rotation interval and the number of advertisers are agreed with you and the site owner. Authorities may regulate moving faces differently from static ones, so we raise the point early in the approval process. The relevant authority is usually the local municipality, with a roads authority involved near its roads, and the landowner must consent.
We assist with the application and supporting documents, but approval rests with the authority. Cost and timing depend on the structure, site and approvals, and are confirmed on your quotation.
Artwork and creative planning
Three images that share a face need to be planned together. Each creative is cut into strips and interleaved with the others, so the files must match the louvre width and the order of the sides. Colours, edges and fine detail should be checked, because a small misalignment between strips is visible from the road.
We guide you through file preparation, proofing and the fitting order, and our flighting crews check alignment on site. Our artwork requirements guide lists file formats and resolutions, and our team can adapt your existing designs on request.
At a glance
Trihedron billboards use rotating three-sided louvres to show three different messages in turn on one face, giving advertisers movement and a shared position without a digital screen. Billboards Africa designs, fabricates, installs, flights and services trihedron billboards for advertisers, media owners and landowners in Gauteng, throughout South Africa and across Africa. A trihedron billboard works best where traffic is slower or queues, such as business districts in Sandton and Rosebank, shopping-centre approaches, city arterials and busy intersections in Durban, Cape Town and Pretoria.
A trihedron billboard needs more than a frame and a skin. The louvres, motor and drive require a reliable power supply, which can be grid or solar, and a service plan so that the mechanism keeps turning in step. Printed strips must be prepared and fitted in sequence, so artwork and flighting are handled carefully. Moving faces may be treated differently by the approving authority, so we raise that early and assist with the municipal and roads authority applications. Tell us about your site and campaign and we will confirm what a trihedron can do for you.
Common questions
How many advertisers can share a trihedron?
Up to three, one on each side of the louvres. The same advertiser can also run three creatives.
How often does the face rotate?
The interval is set when the mechanism is configured. We agree it with you and, where required, with the approving authority.
Is a trihedron better than a digital billboard?
They solve similar problems differently. A trihedron is mechanical and uses printed skins, while digital screens change content electronically and are subject to brightness and hours restrictions. We can advise on which suits your site.
What happens when the motor fails?
We repair or replace the drive as part of our maintenance work. A service plan reduces the chance of an unplanned stop.
