Modeling and Animation of the Tower Clock of the Munich Frauenkirche

Modeling and Animation of the Tower Clock of the Munich Frauenkirche

Abstract

This report describes the 3-D solid modeling of the tower clock in Munich’s Frauenkirche (main Munich cathedral). A 3-D solid model of the clock was constructed by measuring the individual parts and constructing CAD models of them in SolidWorks. Animations of the workings of the clock were created for documentation purposes and for the purpose of showing the public how such a clock worked. This work was carried out by project students of the Munich University of Applied Science for the DeutschesMuseum in Munich. The team involved in the project was an international team of mechanical and industrial engineers from Germany, the United States, and Finnland.

Keywords

Clockworks, tower clocks, SolidWorks, solid modeling

Acknowledgments

Table of Contents

List of Figures – Finnish Students

Introduction

History

Johann Mannhardt and the Frauenkirche Clock

The clock modeled in this project dates from 1842, when it was placed in service in Munich’s Frauenkirche. The clock was designed and built by Johann Mannhardt, a renown clockmaker of the time. Mannhardt made clocks from 1826 until into the 1870s. Many of these clocks represented steps forward in the technology of clockmaking and indeed of mechanical engineering in general, since clockmaking lies at the center of mechanical engineering development in the mid-nineteenth century. Mannhardt was a tinkerer. His forte was machine tool development. With improvements in machine tools that he pioneered, he was able to make mechanical parts much more accurately than they had been made up to that time, which led improved timekeeping in horology (the science of timekeeping). Precision and repeatability in manufacturing also spurred the concepts of standard replacement parts and mass production (Ackermann,***).

Mannhardt’s tinkering nature, however, made him a poor manufacturing businessman. He was always improving something and thus usually only made finished manufactured pieces in small numbers. “Intellectual property” was a foreign concept at the time. Indeed he felt the compulsion to be completely free and open with his discoveries. Thus, even though he made numerous innovations in horology and other areas, his company never grew into an industrial giant like later companies did.

The Frauenkirche clock remained in service until into the 1960s, so for about 120 years. At that time it was removed from service, and the clockworks were moved into storage at the DeutschesMuseum in Munich. There they remained until 2007, when the decision was made to renovate the works and put them on display in the Museum’s library. The importance of this clock to the city is evident in that the Museum’s big statue of Goethe will have to move out of the library’s lobby into the reading room to make way for the clock. But the renovated clock will only be a static display, i.e. it will not run. Hence the wish and need arose to use computer animation to show and explain to the public the workings of this innovative timepiece.

Over the years the Mannhardt clock was modified a number of times to introduce improvements or fix existing problems. Thus the clock modeled in this project is not a pure, mid-nineteenth century original. The purpose of the project was to model the clock “as was”, i.e. as it was at the time of its retirement in the 1960s. Eventually the model may be modified and supplemented to try to model the original Mannhardt 1842 clock.

MechanicalTower Clocks—A Short History

Tower clocks are ubiquitous in Europe and indeed in the United States too. Many of the European clocks appeared in what is called the late middle ages industrial revolution in the sixteenth and seventeenth centuries. Tower clocks were important to society because wristwatches and pocket watches did not exist. It was important to place a clock in a tower so that it could be seen and heard from long distances.

The clocks from the 1500s and 1600s were crude mechanisms compared with later clocks. The precision was that of the woodworker or blacksmith, in fact often the parts were made from iron and wood. The initial tower clocks were not pendulum clocks. The understanding of pendula was unclear until Galileo’s pendulum experiments in the late sixteenth and early seventeenth centuries (Van Helden, 2004). The early tower clocks used a verge and foliot mechanism to mark the time (Headrick, 2002). These clocks were notoriously inaccurate because of their imprecise manufacture. They were placed in clocktowers exposed to bitter cold and sweltering heat, used perhaps animal fat or vegetable oil for lubricants, were exposed to bird droppings. All of these environmental influences could affect the speed at which the clock marked time. Despite these problems, the use of the pendulum as a time-marking device was a big step forward in clock accuracy. This occurred in the seventeenth and eighteen centuries.

During the nineteenth century the industrial revolution caused sweeping changes in all aspects of life. The advent of the steam engine provided a very strong impetus to develop machines with higher precision and materials with better wear characteristics. These features are evident in the Mannhardt clock.

The Tower Clock at the DeutschesMuseum

Dresden Project – Professor Owen

Description and problems found

Similarities to this project

The Need – Professor Owen

Clock Displays in the DeutschesMuseum

The Importance of the Mannhardt Clock to the Museum and Munich

Background

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The Project

The Team

The project team consisted of seven students—two Americans, three Finns, and two Germans. Below you will find short descriptions of each student’s background.

Jesse Chestnut-Linn

Another member of our international team is Jesse Chestnutt-Linn. Jesse comes from the CaliforniaPolytechnicStateUniversity in San Luis Obispo, California, U.S.A. As a fourth year Mechanical Engineering major, he has had some experience with projects like this one. Jesse was born and raised in the northern part of California, U.S.A. and thus his mother tongue is English. Before he came to Germany, he did study German for two quarters. He had a small working knowledge of the German language, though far from fluent, but still enough to be helpful in a project like this where collaboration with people who had little knowledge of the English language was necessary.

Through his studies at the CaliforniaPolytechnicStateUniversity, Jesse was also one of the only members on the team who had experience with solid modeling programs, and the only team member who had actually worked with the Solid Works program previously. Though many of the students learned the program quite quickly, especially those with previous knowledge in other modeling programs, this was to his advantage. Through his studies at his home university, Jesse had taken two previous courses with the Solid Works program, which greatly helped at the beginning of the project.

Hunter Howe

Hunter Howe was born in Chapin, South Carolina. He studies at ClemsonUniversity in Clemson, South Carolina. He has studied Mechanical Engineering for the past five years in the university as well as German for the past three years. August 11, 2007 he will graduate from university and begin working industry. His knowledge of written German far exceeds his conversational understanding therefore during his stay it has been very important for him to further better his conversational fluency.

Since this is his ninth semester in academia, he has had a great deal of experience of project groups. This group proved to be quite different than others he has experienced throughout school and industry with such different culture backgrounds. Although he has a great deal of experience with programs such as AutoCAD and SolidEdge, his knowledge of SolidWorks began as novice. Through tutorials and help of other students, he was able to quickly become proficient in the program.

Levent Sahin

Levent Sahin comes originally from Turkish decent, yet he is now a German citizen as of this past year. He has studied at two institutes during his years in higher education. He began at Fachhochschule Augsburg, but he transferred to Fachhochschule München a year and half ago. He is currently in his seventh semester of Machine Engineering. He has a working knowledge of English and Turkish, but his mother tongue is German. This has proved to be very helpful for the other team members by being able to easily communicate with museum employees. Although his conversational English is sufficient, he has found it increasingly difficult to discuss matters that include a great deal of technical terms.

Like most of the others, Levent had no previous knowledge specifically with SolidWorks. Although he had never previously used SolidWorks, he had used another solid modeling program entitled SolidEdge. This knowledge helped him to easily pick up SolidWorks, therefore making him an integral group member in teaching others as well as modeling more difficult parts. Being his seventh semester, he has had much experience in project work ranging from construction of cranes to subway engines.

Its International Composition

The Frauenkirche Project group consisted of several nationalities. The group included students from American, Finnish, and German universities. This diversity helped to shape the project itself, as it brought many different cultures into a single group. The group was established much like that of many corporations in today’s business world. Today’s globalized projects are worked on by many different people, and quite often the project group may scale the entire world. The differences in culture must be understood taken into account in order to achieve a successful project outcome. The team found that in accommodating cultural differences, it was advantageous for the team. Four major differences came to the forefront as the project details began to unfold: language, fields of study, software, and project organization methodology.

Although each member of the team could converse in English, several times the group encountered problems discussing issues with personnel of the DeutschesMuseum. Quite often the employees at the Museum had a hard time explaining different aspects of project to much of the group in English, so that it was in terms that could easily be understood. With the help of the German students, each time a moment of confusion was encountered, they were able to explain the dialogue in a way that all of the students could fully understand it.

As with all successful corporate project groups, the company must use employees that come from several different backgrounds in order to create a team that can evaluate a task from different perspectives and tackle it most effectively. In a similar way, the Fachhochschule München was able to attract students from several fields of study in order to create a diverse team.

The Various Levels of Experience

Another major difference that was found was the students’ knowledge of solid modeling programs. Students exhibited fairly complete solids-modelling fluency, some familiarization with sold modeling, or no experience whatsoever. Since the program chosen by the school and Museum was SolidWorks, each student was required to be able to work with this program. Only one student had used this particular program previously. Three other students had used several other modeling programs, including SolidEdge, Catia, and AutoCAD. Only the three students from Finland had no previous knowledge of modeling programs. This was only a result of their field of study, yet each had a great desire to understand how to use SolidWorks. One reason for the selection of SolidWorks was its reputation as being fairly easy for beginners to pick up.

It was found from the members of the group with some previous knowledge of modeling programs that SolidWorks was comparable to the other known programs, therefore it was only a matter of understanding the similarities and differences between each program. Because of the similarities, the four students with previous solid modeling programs were able to help in teaching the other students how to use the program. This proved to be helpful for both types of students. It allowed the students with some previous knowledge to understand SolidWorks more thoroughly by teaching others how to use many of the features of the program. It also allowed the other students the ability to learn a program from fellow group members. Both sets of students were able to pick up much of the programs basic features quickly and successfully. The early intra-team training also helped form cohesiveness within the team.

How these Different Levels Were Dealt With

Since the program and the goals of the project were very diverse, the project lent itself to a strategy of “divide and conquer”. The work was divided up to suit the individual interests and capabilities of the students. Students with experience in solid modeling, for example, were given the task of scouting forward, exploring advanced features within SolidWorks in order to accomplish all requirements of the project. Once again this gave the opportunity for students to become knowledgeable about an aspect of the program and then share their knowledge with the others. Some of the features that the team needed to investigate were creation of assemblies and specific mating features, SolidWorks’ animation capability, detailed engineering drawings, and advanced modeling features to accommodate the modeling of difficult parts. Students were able to navigate successfully through arising project difficulties by pre-learning capabilities that were expected to be needed as the project progressed and became more complicated.

The final obstacle that the group encountered was the group’s different methodology of project organization. As with any project, project members’ opinions may be different with how a project should be organized. Many times this is not rooted in cultural differences but in other differences, such as personalities or fields of study. Therefore all successful projects are marked by their ability to set forth a specific plan. This plan is generally set by someone with more experience. This team was very fortunate to have a visiting faculty member of CaliforniaPolytechnicStateUniversity to be involved with the project. His knowledge of project management with both school project teams and industry project teams helped to define a specific path. This with the input of the students involved helped to create a successful plan.

As found by the team on numerous occasions, a difference, when used correctly, will always create an advantage for the group. Since the three Finnish students studied Logistics Engineering, they were able to help in the creation of an organized path of completion with the means of a Gantt Chart. This chart, Figure ***, can be found below showing how the path was organized for the students.

As it has been mentioned several times previously in this section, the project team members found that, even though differences were found within the structure of the team, they could use these differences to their advantage in order to accomplish the desired goal.

The Software

SolidWorks

In order accomplish the goals of the project; each member of the team was given a copy of the solid modeling program SolidWorks by SolidWorks, Inc. This diverse program includes many different features. The features used by the team were modeling, assembly, animation, and engineering drawing. The following sections will delve into the each feature.

Modeling

Solid modeling is the backbone of any modeling project. This feature allows the user to take a conceptual design or actual measurements and create a three-dimensional computer representation. Since the clockwork was created previously without the help of a program like SolidWorks, the students used the feature to create a model from measurements taken from the mechanism.

In order to create such intricate designs you have to use the modeling features given within the Part section of SolidWorks. Within this section, the user has the ability to take two-dimensional shapes and create three-dimensional designs. Figure (1) shows drawing space given at the beginning of every creation with the three possible design planes: top, bottom, right.

Figure 1 : Example of SolidWorks working space

The most commonly used feature for modeling is the Extrusion feature. This allows the creator to define a definite shape then, by means of specified distance, is able to extrude a three-dimensional figure from the specified drawing planes. Figures (2) and (3) show how a basic sketch is defined on a plane and then extruded at an arbitrary distance.