Leonardo Da Vinci (1952 - 1516) [1] was an artist, sculptor, musician, anatomist, scientist, engineer, mathematician, and botanist. Besides his captivating art work including paintings and sculptures, Leonardo was an engineer and a scientist, conceptualizing inventions that were more than 400 years ahead of his time. Unfortunately, Leonardo was never able to materialize most of his inventions mainly due to impracticality, and most of his ideas remained a bunch of drawings and blueprints in his journals. However, there has been recently a renewed interest in testing his hypotheses. Surprisingly, when a number of his ideas were put together, it turns out that they do actually work!! Most remarkably, Leonardo's original Parachute which was tested by an actual human (I saw this on Discovery. Sorry, no references). Though some of them would not work (such as the Helicopter [7]), while others required minimal modifications (such as the Tank [10]).

Clos Lucé. Photo courtesy of (1)

Clos Lucé [2]-[4] (pictured above), is a mansion in Loire Valley, France, that became Leonardo Da Vinci's home for the last three years of his life (1513 - 1516) when François I of France invited him and gave him access to the mansion so that he can live and work there. The mansion has been converted to an exhibit featuring over 50 models of Leonardo's invention, some of which are real-life scale. Whether or not these models would work in reality, visitors of the exhibit can't interact with most of the model in the way it is supposed to be used for. For example, you can interact with the helicopter by turning a wheel that rotates its rotors, but the model itself is fixed and can't fly. You can also look at the hang glider, but you can't fly with it (despite the fact that it actually works [9]). Therefore, an immersive VR environment that allows the general public to learn about these inventions and try them out would be a highly entertaining and educational experience.

The hardware for this project will consist of the C-Wall passive stereo projection display, a head tracking sensor attached to a pair of passive glasses, and a wand with a 3-button joystick and a tracker. Only one hand (the right hand by default) is tracked. I have opted for the bare minimum VR setup to avoid overwhelming the inexperienced visitors with so many trackers, and to lower the costs of the hardware.

The virtual environment

The virtual environment I propose here consists of three sections:

• The art gallery: features some of Leonardo's iconic painting, as well as his hand-written journal
• The workshop: Here the visitor gets to look at and interact with Leonardo's automobile. Also, the user can look at Leonardo's real-sized tank and get inside it.
• Leonardo's outdoor Flight Lab: a platform overlooking a harsh cliff from which the user can launch him with Leonardo's hang glider (which works), and try the helicopter (only to find out that the design does not work).

Initially, the user starts at the art gallery, progresses through the workshop, and finally ends the experience by trying Leonardo's hang glider. However, The user do not need to follow this sequence, and can walk freely through the virtual environment. The emphasis in this environment is on the inventions and the art work, rather than the architecture of the building itself. However, the architecture and design of the building (from the inside) would reflect the period of early 1500.

Leonardo's model

Leonardo Da Vinci himself plays the role of a guide to this environment. Leonardo first introduces himself, welcoming the user to his house. After that, Leonardo follows the user as he/she is walking around in the virtual environment. When the user seems to be interested in a piece of art work or invention, Leonardo starts talking about the object of interest, explaining briefly what it is about, and how it works. The explanation is highly simplified and consists of no more than 5 sentences. The user don't have to listen and can walk away. Leonardo realizes this, stops talking, and patiently follows the user again. Additionally, when the visitor comes upon an interaction, Leonardo provides instruction on how to interact with that particular object (after explaining the science behind it). For example: “Touch the wheel with your hand and press the left button to grab it…”. Therefore, the museum attendant assumes no role while the visitor is experiencing the VR environment, and her only job would be to help the visitor put on the hardware with very few instructions in the beginning on how to hold the wand, move it, etc… I opted for minimizing the role of the attendant because I believe if she interfered with the visitor while he/she is experiencing the environment, she would spoil the immersion component. Therefore, all information, explanations and instructions should come from the environment itself. However, the attendant should standby the visitors in case they require any help.

To overcome the language issue, Leonardo can be told which language he should be using when the application is started. For a US based museum, two languages can be first built into the application: English and Spanish. Later on, more languages could be added if there is interest in the application. Having Leonardo loudly talking in one language (in one execution instance) should be sufficient, since a group of people looking at the C-Wall display would have most likely come together (90% of public museum visitors come in groups), and would be expected to speak the same language.

Overview of Clos Luce in the virtual environment

Although our virtual experience takes place in Clos Lucé, our rendering of the building from the inside will not reflect the actual design of the mansion since the main focus of our application is Leonardo's inventions. We also assume that Clos Lucé overlooks a harsh cliff from its west side. With this assumption, we can append the imaginary Leonardo Flight Lab (LFL) to the building. The LFL allows testing of man-powered flying machines. The rendering from the building from the outside will be very close to the actual medieval mansion. This is significant since the user will be able to fly around the mansion with the hang glide.

Leonardo's Art Gallery

Leonardo's art gallery is the entrance point to our virtual environment. The gallery is housed in an oval shaped room, featuring some of his iconic paintings. The number of paintings will be between 6 and 10. Possible choices include: Baptism of Church, Adoration of the Magi, Virgin of the Rocks, La Gioconda, …

Courtesy of (6)

When the user seems to be interested in a painting, Leonardo starts talking about the painting, explaining what it is about. The user can press the second (middle) joystick button to silence Leonardo, or to repeat the explanation.

In addition to the painting, Leonardo's Journal can also be seen among the paintings.

The user can skim through the pages of Journal and look at Leonardo's drawings and remarks. To flip pages, the user moves the hand to the bottom left/right portions of the Journal and pushes the 1st joystick button (left button), which will flip the page left/right. Leonardo will also explain what the current page is about. The number of pages included in the virtual Journal should be about 6 to 10 pages. Possible choices include:

Leonardo's Journal. Courtesy of (5)

The purpose of the art gallery is to learn about the art work and the Journal. Additionally, it serves the purpose of familiarizing the visitor with the VR hardware and environment since the interaction here is simple and straight-forward.

The workshop

Once the visitor is done with art gallery, he/she will walk through the door leading to workshop and Leonardo will follow. The workshop feature two main attractions:

• The Tank
• Leonardo's automobile [5]

Leonard is famous for his work on advanced war machines while working for the Duke of Milan. The tank is an armored car that was designed to go ahead of infantry in battle. It is operated by 8 men who move cranks to turn the wheels. It has an armored outer shell containing holes through which weapons can be fired.

Leonardo's Tank. Courtesy of (3)

Our virtual tank will be a full-sized model of the real one. Since Leonardo's original tank would not have worked (without some modifications [10]), the virtual tank will also not work, but the visitor will still be able to go inside it and listen to Leonardo's explanation.

The automobile was also one of Leonardo's inventions that do actually work [5].

Leonardo's automobile. Courtesy of (4)

When the user approaches the automobile, Leonardo starts explaining its concept, and gives verbal instruction to the visitor on how to operate it.

The interaction with the automobile will be exactly in the same way as Leonardo envisioned. The user first uses the wand and grabs the first wheel by pushing the 1st joystick button. The hand grabs the wheel, and the visitor rotates the hand in a circular motion to turn the wheel, which turns some springs causing them to store the mechanical energy. The wheel stops turning when the springs are compressed to the maximum level, and the user shall press the 1st button again to release the wheel. The same process is repeated on the other wheel. After that, the automobile is “charged”, and ready to go.

When Leonardo realizes the visitor has charged the automobile, and he instructs him/her to step onto the automobile. Upon that, Leonardo pulls the safety-string, which releases the energy stored in the springs and causes the automobile to move. The user can grab the “steering wheel” using the 1st joystick button and steer the automobile. There are no breaks, however, as Leonardo did not anticipate their importance. The energy stored in the springs allows for about 40 seconds of non-stop movement, after which the car stops automatically. The visitor steps down and continues the tour.

The imaginary Leonardo's Flight Lab (LFL) is the final part of our virtual environment. It is perhaps also the most interesting part. The lab consists of an outdoor platform covered by a big umbrella. There is a rail to protect people from falling. However, a portion of the platform has no rail, allowing the visitor to launch him/her self with the hang glider.

Some of Leonardo's fascinating machines include a helicopter and a hand glider. The helicopter's design turned out to be flawed. However, the hang glider does actually work [9]. In this section of the virtual environment, the visitor gets to try Leonardo's helicopter and hang glider.

Leonardo's helicopter is one of the first helicopter designs/concepts in the history.

Courtesy of (7)

Leonardo starts explaining the concept of the helicopter when the visitor approaches it. He makes clear that the design is experimental. However, the visitor seems very excited to try it. Leonardo agrees to let the visitor test the helicopter and instructs him/her to get on board. The interaction with the helicopter involves the user grabbing the handle of the rotation wheel with the 1st joystick button, and rotating the hand in a circular motion to turn the wheel. This causes the rotors to turn.

When the rotation speed exceeds a certain threshold, the rotors start to generate lift, and the helicopter starts moving upward. However, as soon as it hovers over the platform, the visitor (who's still turning the wheel), notices that something is wrong. The piece of wood he/she is standing on is rotating in the opposite direction, making him/her turn! The user realizes this and aborts the flight. Leonardo apologizes for this and figures out that his design is fundamentally flawed.

The hang glider can be also seen in the LFL. Leonardo also explains the concept behind it, and gives instruction to the user on how to use it. The user has to approach the glider's “chair” and push the left button of the joystick to get into it. He/she then becomes attached to the glider, and the glider moves with the user as she's moving. The user launches herself by walking through the opening of the rail.

We assume that weather conditions are perfect for hang gliding, and there is enough wind to generate lift. To control the hang glider in the air, the user uses the joystick of the wand in a way similar to most flight simulators (dX for roll and dY for pitch). To simplify flight, we assume that the hang glider can climb (though at a lower rate than descend). The visitor can fly around Clos Luce and its courtyard. After some hang gliding with Leonardo's machine, the visitor shall return to LFL, landing on the platform. Leonardo looks very happy. The VR experience ends.

• Some 15th century classical music can be heard playing in the Art Gallery and the Workshop.
• Outdoor ambient sounds, such as bird singings in LFL platform.
• Light wind howling during hang glider interaction.

• Various rattling sounds resulting from gears and wheels turning for the automobile and the helicopter
• Leonardo's voice

The environment described here is not very difficult to implement. However, to be suitable as a museum exhibit, everything should be highly polished. Therefore, much of the work will be spent on developing high quality 3D models. The surrounding environment (the mansion and the courtyard) should be well designed. Special attention should be given to Leonardo's art work. The animation should be smooth, and well synchronized with the sound. The frame rate should not fall below 24.

Leonardo's animation might pose a bit of a challenge. This challenge can be alleviated by using motion capture to construct a periodic walking animation model.

The simulation of flight dynamics for the helicopter and the hang glider should be simplified to allow for easy navigation.

The VR environment presented above is suitable for use in a museum as a public exhibition for the following reasons:

• The interactions are simple which makes them easier for people with no prior experience in VR environments. Yet, the interactions are engaging and entertaining.
• The environment provides a wealth of information about the art work and inventions of Leonardo Da Vinci.
• The length of the experience is about 15 minutes.

This is yet another example where VR allows us to experience things we could not experience in reality. After all, who would expect to fly in a 15th century hang glider, try one of the earliest helicopter designs in the history, and meet perhaps the most diversely talented person who ever lived.

1. Leonardo's Wikipedia article: http://en.wikipedia.org/wiki/Leonardo_da_Vinci
2. Clos Lucé official website: http://www.vinci-closluce.com/
3. Loire Valley castles, Amboise, Le Clos Luce: http://www.castles-france.net/vinci-clos-luce/
4. Clos Lucé photos http://travel.webshots.com/album/484901219EUybqf?start=0
5. Leonardo's automobile: http://youtube.com/watch?v=a2qeZrejZp0
6. Paddle boat: http://youtube.com/watch?v=MOvUXeQji58
7. Helicopter: http://youtube.com/watch?v=mNyy5Lk8_bw
8. Water pump: http://youtube.com/watch?v=vhoiW_HLhRw
9. U.S. Public Broadcasting Service (PBS), Leonardo's Dream Machine, October 2005
10. http://www.theage.com.au/articles/2002/12/13/1039656218782.html
11. Leonardo as a scientist and inventor: http://en.wikipedia.org/wiki/Leonardo_da_Vinci_-_scientist_and_inventor

1. http://www.flickr.com/photos/benets/844006286/
2. http://www.flickr.com/photos/saskya/22604951/
3. http://icomc23.univ-rennes1.fr/sightseeing-in-brittany.html
4. http://www.dkimages.com/discover/Home/Geography/Europe/France/Western-France/Loire-Valley/Touraine/Chateaux/Chateau-du-Clos-luce/Models-of-Leonardos-Designs/Leonardo-da-Vincis-Car/Leonardo-da-Vincis-Car-1.html
5. http://en.wikipedia.org/wiki/Leonardo_da_Vinci_-_scientist_and_inventor
6. http://en.wikipedia.org/wiki/Leonardo_da_Vinci
7. http://www-03.ibm.com/ibm/history/exhibits/attic3/attic3_174.html