Scrolling Wall

Visual Simulation with a Scrolling Wall

Sam Jewell and Jessica Vechakul worked together to create the visual illusion of descending from the Tech Ops Briefing Room down into the Tunnel via a service elevator. To better understand the motivation for a service elevator in the spy adventure look the Gromits’ storyboard for a service elevator before reading these concept model details.

This page is divided into the following sections:

Video of the model, and existing Elevator

Plans for the next implementation

Complete Model Views

Detailed Views

Mechanical Parts

The visual effect for the service elevator can be achieved with a scrolling image of the inside of an elevator shaft, activated simultaneously with a wind and vibration effect, and a descending motion effect, each of which have been simulated by other Gromits. When the spies have left the service elevator and closed the doors behind them, the scrolling mechanism will automatically reverse to reset the image for the next group.

VIDEOS

Service Elevator we want to Simulate

Current working Sketch model

Here you can see we have a long way to go, before we get the desired user interaction with the elevator. We really want to have two sets of doors, each with latches/handles as shown in the first video.

However, the concept model was useful in determining that a scrolling screen can be effective in creating the illusion of descending in an elevator. We will test this concept model with the other effects of vibration and wind, and the falling motion to see whether these combined elements can convincingly simulate an elevator ride. The final implementation of this visual effect will look more like the sketch below.

PLANNED ELEVATOR ARRANGEMENT

The initial image on the rolling canvas in the door of the elevator is meant to blend in with the solid surface of the door so that the spies will not notice that there is a canvas in the door when they walk past. The spies must close this door, and then another accordion-style folding wire mesh gate before the elevator can begin to move. The accordion wire mesh gate will have some solid segments to block the passengers’ view of the solid parts of the door surrounding the moving image.

The elevator walls will also hide the parts of the solid perimeter of the door which will not move, and the middle section of the accordion gate will do the same. Thus, from inside the elevator it will seem like the whole door (the canvas) is moving up, and only the accordion gate is stationary. See the videos below for the effect we want to create.

The final image on the rolling canvas will also blend in with the door of the tunnel entrance so that when they open the accordion-style gates, they will not be able to notice the difference between the scrolling paper and the rest of the door.

This arrangement will require us to package the rollers very tightly into the door, which will be a challenge. It might also require that there be a step at the entrance to the elevator, which may not be feasible. However, another alternative is using sliding accordion doors (like those in the coffee house in the student centre) to block the riders of the elevator from being able to see the perimeter of the solid door surrounding the scrolling image.

CONCEPT MODEL VIEWS

Front View

Side View

Rear View

Front View
A door was made out of blue foam with a rectangular cut out to represent a window, where the spies riding the elevator can view the walls on the inside of an elevator shaft as the elevator descends. The front cross-section is 32 inches wide and 83 inches tall.

Side View
The scrolling mechanism can fit easily into the profile of a door. The only width necessary that might make it thicker than the average door is the diameter of the motorized-roller.

Back View
The door was made primarily out of foam, reinforced by higher density and stiffer foam around its perimeter. A motorized roller holds the paper at the bottom, while at the top, a spring-loaded roller winds up the paper as it is released by the motorized motor. The back panel was attached to the foam door to provide a flat backing for the scrolling paper so that it would not bulge and ripple as it moves.

DETAILED VIEWS

Front Surface of Door

Shiny silvery paper was spray glued to the front face of a door made of blue foam, and then screwed down to make it look as though it were sheet metal. A sheet of fine wire mesh was sandwiched in between the silver paper and the foam to help create some depth from the image,and to make the image seem less 2D and more 3D.

Back Panel

The back panel made out of foam was too high in friction to allow the scrolling paper to pass over it easily. Acrylic sheets were spray glued onto the foam to give the scrolling paper a more slippery surface to slide over. The acrylic sheets were quite a bit heavier than the foam and made the door harder to move and handle. Thin polyethylene sheets may be used instead. In actual implementation, the ends of this panel would also have rollers to allow the paper to slide pass the end edges more easily.

Scrolling Image of Elevator Shaft (Rotated Horizontally and Smaller Scale)

The image of the elevator shaft was created by taking several pictures inside a service elevator shaft, and splicing the images together with a photo-editing software. A full-scale image was printed out, and attached at one end to a motorized roller and at the other end to a spring-loaded roller.

MECHANICAL PARTS

Motorized Roller

The motor is connected to a disc which is pressed flush against the inside of an acrylic tube. When the spring-loaded roller is too stiff, the motor can slip against the inside of the acrylic tube and not be able to advance the paper. In actual implementation, we may remedy this by making both rollers motorized at the same speed.

Motor Power Source

The motorized roller can be powered by a small voltage comparable to that of a battery. The contacts can be reversed to change the direction of rotation of the motor. For our model, we changed directions manually by switching the alligator clips attached to motor, we could simply attach the wires to a switch or elevator buttons which would indicate up and down scrolling.

Spring-Loaded Roller

The spring-loaded roller was taken out of a set of store-board window blinds. The ratchet in the blinds and the fabric was removed from the cardboard tube before fixing the paper print-out of the elevator shaft onto the roller.

Torsion Spring

The spring must be pre-loaded with just the right amount of tension to be strong enough to wind up the paper as it rolls off the motorized roller, and giving enough to allow the motor to also wind the paper up in the reverse direction. There were some difficulties in working with the torsion spring because it was not made to wind up a length of canvas or paper so long.