Each manufacturing building in Universal Studios, which is been set on fire in movie style for tourists several times every day, causes nostalgic feelings- just like the hall next door, where optical tricks by Alfred Hitchcock are shown. It is only a question of time, until the flames and exploding tons can be generated in the film by pressing a button. The water which surrounded the Titanic, the mountains of ``Dante's peak", the tornado of ``Twister", but also the sunny sky above the runway in ``Apollo 13" were not shot, but calculated. Cartoons like ``Antz" or ``Das grosse Krabbeln" were completely generated by the computer.

It is obvious that designers profit from the computer graphics boom, after all they are the ones who can use the software. Also computer scientists, who write and maintain the software, are needed. But mathematicians? Why do they also get an opportunity? The answer is easy: in movies, videos, and advertising clips the demand for realistic simulations of nature is rising. If the pictures are supposed to not look like cartoons, but like ``real" reality, then it is tempting to use models to generate them which depend on the actual laws of physics. To find methods to solve these often complicated equations is the task of mathematicians. If a designer wants to simulate a fur, then most of the time he still has to draw all the hairs separately on the screen and determine its motion- a time consuming job. This works much better with equations which describe the whole fur under flow of air. The same holds for fire, smoke and explosions which are supposed to look real, or for the simulation of water. In the plugins which are developed by mathematicians, which are special additions to the graphics software, are hidden secrets which allow one to imitate reality astonishingly well, and which give a lead over competitors.

Stan Osher, professor of applied mathematics at UCLA, counts half a dozen mathematical disciplines which one has to master, in order to generate realistic pictures on the screen, from fluid mechanics to differential geometry. Osher was one of the first to realize the market for mathematicians in Hollywood. With his own company he wants to sell his ideas for simulation of water. The Titanic-movie had only waves. ``We can also let the water splash" is how he describes his advantage over competitors.

The physics is important, but what counts is the effect.

Osher is an applied mathematician, an expert on solving mathematical equations with the computer. In the seventies he worked on the simulation of air flow past wings of planes. Later he turned to image processing and co-founded a company which developed software for denoising of video images. He is a master of three dimensional approximation schemes to solutions of the Navier Stokes equation, which is behind all phenomena of fluid dynamics. ``At some point we realized, that one can use the same equations to describe shock waves in fluids" tells Osher. So he began to model water waves.

He gave his former student Ron Fedkiw so much know how, that 30 year old Ron has already made it as a well paid advisor in Hollywood. Fedkiw's main profession is to do research and teach applied mathematics at UCLA and Caltech. His specialization is the modelling of explosions - just perfect for Hollywood (and certainly also sought after in military related research.) His ideas appear in renowned scientific journals such as the Journal of Computational Physics. In Hollywood he makes sure that his realistic simulations turn into spectacular pictures. As an advisor to the production company Arete Entertainment, which has established itself by digital water and fire, he guides the computer scientists to feed his mathematical models into the computer.

``Even if the decisive element is mathematics, the work at Hollywood has 99 percent nothing to do with mathematics" says Fedkiw. One has to be able talk the same language as the movie people. This causes also problems. ``What makes the work at Hollywood so strenuous is, that these people can't wait. One has to be incredibly fast to be always at the top." But at this time the know how is still spread over so few people that Fedkiw does not need to worry. German mathematicians also profit from the introducing mathematics into special effects. Hans -Christian Hege, head of scientific visualization at the Konrad-Zuse center for computer science at Berlin, was co-founder in 1986 of the Berlin based company Mental Images, which has made a name for itself internationally in the development of graphics software. Meanwhile their programs are used by by the major production companies worldwide. Hege himself develops nowadays mainly graphical tools for scientists such as the correct visualization of string theory or bio molecules.

The point of photorealistic simulations for movies is not so much realistic representation of nature, but rather the optical effect. This can cause conflicts: The scientist wishes a correct physical model, the hands-on men need fast algorithms and pictures, which look realistic, but do not have to be realistic. ``This unavoidable conflict of goals makes the scientific challenge" says Peter Deuflhard, president of the Konrad Zuse center and mathematics professor at the Freie Universitaet. ``Proficiency in the physical models that are behind the picture is important" he says. But the models had still to be simplified and the algorithms to be speeded up. ``In complicated situations one has to invent completely new methods" says Deuflhard.

If it were up to him, there would soon be created a team at the Konrad Zuse center, which would deal with the mathematical side of movie production. ``We in Berlin have the know how in all necessary mathematical areas", says Deuflhard. There are also the Babelsberg film studios and film schools in the area.

What is missing is the collaboration with producers. But this is just what makes the challenge for this mathematician, who had contacts to his colleagues in LA for years. ``We in Germany usually see a difference between scientific research and practical applications, which is subject to deadlines. I personally don't see these difficulties" says Deuflhard.

This enthusiasm however is shared only by few German mathematicians. Although the theoretical knowledge is there at many universities, but cooperation with film producers is rare. So it is no surprise, that the ProSieben spring-off SZM Studios, which among other things develops special effects for TV ads etc., has bought 20 percent of Arete Entertainment at LA. This ensures the company access to the most recent developments besides digital fire and water it also includes the coloring software, which was used for the movie ``Pleasantville". ``We would also love collaboration with scientists in Germany" says Gert Zimmermann, in charge of animation at SZM.But so far there had been only few contacts, mostly of former students with their professors.

``It can not be our task to compete with large companies such as Arete" explains Zuse president Peter Deuflhard, giving his opinion. The goal is rather that universities give their knowhow to companies. But the main immediate goal is to find young people who join the efforts. They should realize what their mathematical knowhow can be used for.

This however still has to be circulated. Deuflhard gave a talk at the end of May at the ``day of mathematics" of the mathematical institutes at Berlin on the topic ``maths on the Titanic". The audience was puzzled. The liaison of movie industry and mathematics sounds too good for many to be true. But it is not a fairy tale. Even mathematicians may dream of a career at Hollywood.

The UCLA Department of Mathematics assumes no responsibility for the accuracy of this translation from the German version.