Animation Software Research Articles

Computation and visualization of regional-scale forest disturbance and associated dissolved nitrogen export from Shenandoah National Park, Virginia.

Long-term watershed research conducted in Shenandoah National Park (SNP) in Virginia and elsewhere in the eastern U.S. indicates that annual export of dissolved nitrogen (N) from gaged forested watersheds to surface waters increases dramatically in response to vegetation disturbances. Dissolved N leakage is a common, well-documented response of small forested watersheds to logging in the larger region, while recent defoliation outbreaks of the gypsy moth (Lymantria dispar) larva in the deciduous forests of SNP have been shown to generate similar biogeochemical responses. A recent modeling analysis further suggests that a parsimonious, empirical, unit N export response function (UNERF) model can explain large percentages of the temporal variation in annual N export from a group of small gaged forested watersheds in the years following disturbance. The empirical UNERF modeling approach is completely analogous to the unit hydrograph technique for describing storm runoff, with the model representing annual N export as a linear deterministic process both in space and in time. The purposes of this analysis are to (1) test the applicability of the UNERF model using quarterly streamwater nitrate data from a group of ungaged watersheds in SNP; (2) demonstrate a park-wide application of a regional UNERF model that references the geographic distributions of bedrock geology and the timing and extent of gypsy moth defoliation over the entire SNP area; and (3) visualize the temporal and spatial patterns in vegetation disturbance and annual dissolved N export through the use of computer animation software. During water year 1992, the year of peak defoliation, our modeling study suggests that park-wide export had transiently increased by 1700% from a baseline rate of about 0.1 kg/ha/year. SNP forests appear to be characteristic of other N-limited second-growth forests in the eastern U.S. that leak little N under undisturbed conditions, despite receiving relatively large inputs of N from atmospheric deposition sources. Vegetation disturbances can apparently cause major changes in N input-output balances with potentially important ramifications for low-order forest streams and downstream receiving waters.

3-dimensional movement analysis after internal fixation of pelvic ring fractures. A computer simulation

Several studies exist describing the biomechanical behavior of several external or internal fixation techniques of the posterior and anterior pelvic ring. Recently, the traditional models using isolated anatomical sections or fixed pelvic ring specimens for evaluation of linear or two-dimensional data have been replaced by three-dimensional measurement systems and simulations of muscle forces. These studies have contributed important information to the understanding of the biomechanics of the intact and injured pelvic ring, however, a consequent movement analysis is still missing. In the present study, 3-D data acquired during several series of testing implants for stabilization of the posterior pelvic ring (sacrum: sacral bars, sacral plates, transiliosacral lag screws; Sl joint: anterior plates, transiliosacral lag screws), using a complete pelvic ring model with single leg stance and static abductor muscle simulation, were converted into a commercially available 3-D animation package. By use of simple graphical representation of anatomical elements of the posterior pelvic ring, reproducible and reliable movement patterns for different types of stabilization could be identified, which demonstrated potential "weakness" of the fixation before failure occurred. These movements were analyzed by "replay functions" and were comparable to observations during the original experiment. The following movements were observed. Sacral fracture, transforaminal: (1) rotation of the transiliosacral lag screws around its axis, even with a second screw into S1; (2) Sacral bars: shearing with compression of the cranial-posterior fracture zone; (3) Sacral plates: minimal translation in the proximal fracture zone and distraction in the distal fracture line, effectively compensated by an additional plate at the S3 level. Sl joint disruption: (1) anterior plating (two plates), minimal translation in the plane of the Sl joint; (2) transiliosacral lag screws, rotational movement around the axis of the screws with only minimal movement at the S1 level. The provided information confirmed the observations and allowed a more detailed and comfortable examination of movement patterns. A better understanding of potential "failure zones" might be useful to optimize the dimensions, design, and the positioning of implants for the pelvic girdle. For further studies, more complex computer models including finite element technology might be useful to add accessory information and could result in a decreased need of living specimen testing.

An in vitro study of the accuracy of a new protocol for planning distraction osteogenesis of the mandible

Purpose: The purpose of this study was to determine the in vitro accuracy of a new protocol for distraction osteogenesis of the mandible that involves a planning process and a surgical technique. Materials and Methods: An experimental design was developed to simulate distraction osteogenesis on stereolithographic models of patients with craniofacial deformities. All patients had previously undergone 3-dimensional computerized scans of the craniofacial skeleton. The data from these scans were used to generate stereolithographic models. Before the fabrication of the models, the computed tomography (CT) data were manipulated to add a series of rulers and markers to the models. The 3-dimensional computerized scans were also used as the basis of the planning process. They were imported into an animation software (3D-Studio Max; Discreet, Montreal, Canada), and a virtual distractor was built and installed on the model, and the osteotomies and distraction processes were simulated. Finally, a recipe for sequencing the linear and angular changes of the distractor were calculated. A surgical technique was developed to facilitate the precise installation of the distractor as indicated in the presurgical plan. The transfer of information regarding pin position and orientation from the computer model to the patient was accomplished by creating a surgical template. This template was designed in the computer and fabricated by use of stereolithography. Mock surgery was performed on the stereolithographic models, and the results were compared with those predicted by the computer. The difference between the actual position and the predicted position was recorded. Results: On the X-axis, the difference between the predicted position for the condylar marker and the actual position of the marker on the stereolithographic models was 0.6 ± 1.1 mm. On the Y-axis, the difference between the predicted position for the condylar marker and the actual position of the marker on the stereolithographic models was −0.9 ± 2.6. On the Z-axis, the difference between the predicted position for the condylar marker and the actual position of the marker on the stereolithographic models was 0.04 ± 0.8 mm. There was excellent correlation between the predicted and the actual measurements for the X, Y, and Z axes: 0.98, 0.93, and 0.98, respectively. Conclusions: The results indicate that the combination of this planning process and surgical technique was very accurate. This in vitro study is the first step in determining the clinical usefulness of this protocol. If the results of this study are validated in clinical practice, this protocol will allow clinicians to improve the clinical outcomes of patients treated with distraction osteogenesis. © 2000 American Association of Oral and Maxillofacial Surgeons

Computer planning for distraction osteogenesis.

Distraction osteogenesis of the mandible has found an application in the treatment of patients with a variety of different mandibular deformities. Compared with the relatively simple unidirectional distraction of long bones as described by Ilizarov, the three-dimensional distraction of the mandible is extremely complex. Whereas experience with orthognathic surgery clearly demonstrates that careful presurgical planning is necessary to achieve predictable outcomes, there are few reported methods for the planning of mandibular distraction. The authors have developed a method for planning distraction osteogenesis of the mandible that involves the use of three-dimensional modeling and animation to simulate distraction osteogenesis in virtual reality. The first step in the authors' treatment planning process is to obtain a three-dimensional computerized scan of the facial skeleton. From this scan, a three-dimensional wire-mesh model is built using animation software. With the same software, a virtual distractor is built and installed on the wire-mesh model. The osteotomies and the distraction process are then simulated. Finally, a recipe for sequencing the linear and angular changes of the distractor is calculated. The authors have used this planning process in seven patients (age range, 4 to 10 years): four with unilateral mandibular deformities and three with bilateral. The planning process has yielded predictable and reproducible results.

Uses of animated imagery within the software learning environment

The increase in the hardware and software capabilities of interactive media has allowed an increase in the use of animated imagery within software learning environments. New animation software programs, targeted specifically for use on the World Wide Web (WWW) and CD-ROMs, have been introduced into the market place for programmers, designers and others who may have little training or experience with incorporating animated imagery into interactive content. This paper provides an overview of theories which relate to motion in the areas of education, science and culture. This paper is not meant to be an exhaustive source, but more of a reflective piece on work done in other fields that relates to animation within software. The final portion of this paper lists six common uses of animation in learning software, as well as ten recommended guidelines for evaluation of animations within a software learning environment.

High-level interpretation in virtual environments

As virtual environments applications become more complex, there is a need to interpret user interaction in terms of high-level concepts. In this paper, the relations between conceptual representations of actions and their physical simulation in virtual worlds is investigated. A model inspired fromnatural language processing (NLP) research in the linguistic interpretation of dynamic scenes has been developed. The experiments are based on real-time animation software, which has been enhanced with a symbolic information processing layer, originally developed for NLP-based animation. We report the implementation of a high-level interpretation module that is able to recognize complex actions fromlow-level physical events in the virtual world and discuss its performance as well as directions for further developments.

Validation and application of dual-energy X-ray absorptiometry to measure bone mineral density in rabbit vertebrae.

The rabbit could be a superior animal model to use in bone physiology studies, for the rabbit does attain true skeletal maturity. However, there are neither normative bone mineral density (BMD) data on the rabbit nor are there any validation studies on the use of dual-energy X-ray absorptiometry (DXA) to measure spinal BMD in the rabbit. Therefore, our aim was twofold: first, to investigate whether DXA could be used precisely and accurately to determine the bone mineral content (BMC). bone area (BA). and BMD of the rabbit lumbar spine: Second. to evaluate the new generation fan-beam DXA (Hologic QDR-4500) with small animal software by comparing two DXA methodologies QDR-1000 and QDR-4500 with each other, as well as against volumetric bone density (VBMD) derived from Archimedes principle. As expected. there was a magnification error in the QDR-4500 (BMC, BA. and BMD increased by 52%. 38%. and 10%, respectively, when the vertebrae were positioned flat against the scanning table). With the magnification error kept constant (vertebrae positioned 10 cm above the scanning table to match the height in vivo). there were no differences among the mean BMC. BA. and BMD of the rabbit vertebrae (Ll-L7) in vivo and in vitro using the QDR-4500 (p > 0.05). BMC, BA, and BMD differed between QDR-1000 and QDR-4500 in vitro because of a magnification error when the vertebrae were flat on the table (p <0.0001). and, consequently. the machines did not correlate with one another (p > 0.05). However, the BMC, BA, and BMD of the two DXAs did significantly correlate with each other in vivo and in vitro when the magnification error was compensated for (r = 0.44 and 0.52. i2 = 0.45 and 0.63. and 12 = 0.41 and 0.60. respectively. p < 0.05-0.008). The BMC and BMD (in vivo and in vitro) of the rabbit vertebrae measured by QDR-4500 was significantly correlated with VMBD, ash weight, and mineral content (,2 = 0.67-0.90,j <0.01-0.0001). Therefore, the QDR-4500 can be used to yield precise and accurate measurements of the rabbit spine.

Design and validation of a machine for reproducible precision insertion of femoral hip prostheses for preclinical testing.

Preclinical testing of orthopaedic implants is becoming increasingly important to eliminate inferior designs before animal experiments or clinical trials are begun. Preclinical tests can include both laboratory bench tests and computational modeling. One problem with bench tests is that variability in prosthesis insertion can significantly influence the failure rate; this makes comparison of prostheses more difficult. To solve this problem an insertion method is required that is both accurate and reproducible. In this work, a general approach to the insertion of hip prostheses into femoral bones is proposed based on physically replicating an insertion path determined using computer animation. As a first step, the seated prosthesis position is determined from templates and femur radiographs. Three-dimensional images of the prosthesis and bone are then imported into computer animation software and an insertion path in the coronal plane is determined. The insertion path is used to determine the profile of a cam. By attaching the prosthesis to a carriage, which is pneumatically moved along this cam, the required insertion motion of the prosthesis in the coronal plane can be achieved. This paper describes the design and validation of the insertion machine. For the validation study, a nonsymmetric hip prosthesis design (Lubinus SPII, Waldemar Link, Germany) is used. It is shown that the insertion machine has sufficient accuracy and reproducibility for preclinical mechanical testing.

Ergonomic design using computer animation

Computer animation was used to evaluate and improve the ergonomics of an existing cut-up saw workstation in a poultry-processing plant. Based on ergonomics audits of different poultry processing facilities, the manual cut-up saw was identified as one of the workstations having a high incidence of cumulative trauma disorders. A high-end commercial animation software package was used to develop a tool that could be used to measure body joint angles during the performance of the workstation task. Three-dimensional CAD models of the workstation and workers were developed and imported into the animation software. After the data for the existing design was collected, and the computer model was verified, modifications were made in the workstation design using computer animation. The joint angles for the shoulders, elbows, and wrists were significantly improved by lowering the saw four inches, rotating the guide bar 20 degrees, and lowering the bag holder and shackle line. Joint forces and moments were determined to evaluate the proposed design modifications.

Animated Heads from Ordinary Images: A Least-Squares Approach

We show that we can effectively fit arbitrarily complex animation models to noisy data extracted from ordinary face images. Our approach is based on least-squares adjustment, using of a set of progressively finer control triangulations and takes advantage of three complementary sources of information: stereo data, silhouette edges, and 2D feature points. In this way, complete head models—including ears and hair—can be acquired with a cheap and entirely passive sensor, such as an ordinary video camera. They can then be fed to existing animation software to produce synthetic sequences.

Flash Cards and Animation Software for Education

s English: The article describes how a compiled program for DOS/Windows manages a collection of pictures such as photographic slides, overheads, or computer images in one or more databases.

Evaluation of Lunar Small Animal Software for Measuring Bone Mineral Content in Excised Rat Bones

The purpose of this study was to evaluate software from Lunar Corporation (Madison, WI) designed for the measurement of bone mineral content ([BMC],g) in excised rat femurs using dual-energy X-ray absorptiometry (DXA). Femurs were harvested from intact 2- to 12-mo-old female Sprague-Dawley rats, stripped of soft tissues, wrapped in saline-soaked gauze, and frozen at -20 degrees F. Thawed bones were scanned in air on a 1.7-cm-thick Lucite plate that was laid on the manufacturer's supplied Delrin platform. Bones were in an anteroposterior position and scanned in a proximal-to-distal manner. Small animal software version 1.0d was used with a Lunar DPX-L densitometer. Regions of interest (ROIs) were the middle one-third of the diaphysis, a small central area of the distal metaphysis, and the total bone. Precision (n = 6 femurs) was calculated for each region of interest. After DXA scanning, one group of bones (n = 10 femurs) was dried and incinerated in a muffle furnace to obtain bone ash. The ash was then digested in acid and aliquots assayed for calcium using atomic absorption spectrophotometry. This group of bones was used to correlate BMC with ash weight and areal bone mineral density (BMD) with calcium concentration. A second group of bones (n = 14 femurs) was used to correlate BMC with maximal load to failure (N), a biomechanical variable that provides information about bone strength. Precision of repetitive measurements for the three ROIs was 1.2, 3.0, and 0.65%, respectively. Total femur BMC and total femur ash weights were significantly correlated (r = 0.974, p <0.0001). Total femur area BMD (g/cm2) was significantly correlated with calcium concentration (microM) of the bone hydrolysate (r = 0.686, p = 0.029). Total femur BMC and maximum load to midshaft fracture were also significantly correlated (r = 0.914, p<0.0001). The greatest problem with the software was with edge detection: operator intervention was necessary to place edges manually during scan analyses. We conclude that the small animal software from Lunar Corporation accurately and precisely measured BMC in excised rat femurs. However, poor edge detection resulted in tedious and time-consuming analyses.

Exploring the Use of Animation Software with Young Bilingual Students Learning Science

This study investigates those practices associated with the design, creation, and revision of animated models that tell a science story. It reveals information about how animation software assists young bilingual children in science learning. The article argues that bilingual children benefit from the ability of animation software to displace and reassemble spatial and temporal relations in science (with the effect of shaping language). Evidence that animation software displaces and reassembles knowledge in science is exposed by 1) having accessibility to different worlds, 2) the capacity to manipulate science concepts, and 3) connecting structure and sequence to function. The study suggests that this type of visual displacement and reassembling is a starting point for the development of science discourse in English among bilingual children.

Extreme Motion Analysis and Simulation for Ship Design and Operations

ABSTRACTNaval architects of the world use static approximations to allow for dynamic effects in the prediction of stability. With the advent of powerful computers, engineers can now model dynamic responses of ships within hours and operational staffs can have the benefit of these capabilities in a more real time setting.Six years ago a Cooperative Research Navies (CRNav) project was established to develop dynamic stability criteria and study the physics of extreme motion phenomena. The project is sponsored by a Dynamic Stability Working Group which includes members from the Australian, Canadian, Netherlands, United Kingdom, and United States Navies, and U.S. Coast Guard along with the Maritime Research Institute Netherlands (MARIN). As a result of the work done to date, a time domain motion analysis program has been developed. This program includes the capability to model a steered ship in extreme sea conditions and display animation to allow the user to visualize surfriding, broaching, capsizing and other extreme events. The use of this program and the criteria developed from the CRNav project will lead to significant improvement in the various nations' ship design and operational guidance capabilities. This paper outlines work done to date to develop a dynamic stability analysis system and includes a discussion of the Cooperative Research Navies project: explaining findings for capsizing physics and criteria; the time domain ship motion simulation program FREDYN, including its animation software and validation; proposals for extensions to damaged ship conditions, and the future of U.S. design and operational applications.

A microprogramming animation

This paper describes a successful project using computer animation to teach the concepts of microprogramming to lower division computer science majors. The students write a simulator for the Mic-1 horizontal microcontroller described in the book Structured Computer Organization by Tanenbaum. The simulation is enhanced by the use of a graphical representation of the machine to animate the simulation. This creative use of computer animation enables the students to see the results of their simulation without having to write an extensive user interface. They can concentrate on implementing the instruction cycle, an activity that directly enhances their understanding of microprogramming and the conventional machine level. The XTango animation package is used, making the animation facility portable to any Unix system with an X display. The user interface and additional instructional material are available via the web.

A phantom for evaluating bone mineral density of the hand by dual-energy x-ray absorptiometry

Dual-energy x-ray absorptiometry (DXA) is a precise, widely used method for measuring bone mineral density (BMD), usually of the lumbar spine and femoral neck. Recent developments, such as a lower x-ray tube current and pixel by pixel analysis, enable smaller bones and thinner tissue volumes, as in the hand, to be measured. Measurements of hand bone mineral content (BMC) and BMD could be useful in assessing disease severity in early rheumatoid arthritis and in monitoring disease progression and response to therapeutic intervention. A phantom is required for evaluating the software, measuring long-term precision and comparing with other DXA methods. This note describes the design and evaluation of a hand phantom for use on a Lunar DPX-L dual-energy x-ray absorptiometer. The phantom consists of three sections representing the metacarpals, and proximal and distal phalanges, using aluminium and Perspex as the bone and lean tissue equivalents respectively. The BMD of the three sections is approximately 1.0, 0.6 and . The phantom demonstrates limitations in the potential accuracy of BMD determination at low densities using the Small Animal Software on the Lunar DPX-L. Improved recognition of low-density regions was obtained with the Lunar EXPERT with precision values of 0.9, 1.1 and 2.0% for the three sections of the phantom respectively. Keywords: hand, phantom, bone densitometry, DXA

The creative process of animating human movement

The computer animation of articulated models such as human figures can be regarded as a complex synthesis task much like composing a musical piece or designing a new product. Developing computer animation tools requires a sound understanding of both this creative process as well as the animation task itself. Most current commercial animation packages focus on providing useful but low-level functions to create, modify and compose human movement. This paper proposes a hierarchical approach to human figure animation which incorporates knowledge on several levels about movement and motion processing in order to support the creative process and facilitate the motion specification task without taking control away from the animator. Two examples are given to illustrate this principle: a tool for animation of human locomotion, and motion signal processing techniques to adapt existing motion data.

Automatic Generation of Animated Migration Maps

Thematic cartographers have used numerous techniques to portray the spatial and quantitative aspects of human migrations: choropleth maps, graduated symbol maps, and, most commonly, flow maps. Unfortunately, these methods all have serious shortcomings, particularly when used to map complex movement patterns. This paper proposes and demonstrates a new technique: automatically generated migration mapping. This technique automatically produces animated visualizations directly from a data base of net migration counts without the need for any other drawing or animation software. The method animates vector field maps according to the model set forth in 1885 by Ernst Ravenstein in his ground-breaking work on migration. Automatically generated migration animations are intended as tools for the exploration of migration data, allowing the viewer to perceive geographic patterns of flow through the combined motion of many small symbols moving independently across a background map. Symbol size and colour present information regarding relative migration quantities. Separate animations have been constructed using the traditional flow map symbol shape, the arrow, as well as a symbol shape rarely employed for mapping flows, the circle. The method is demonstrated by mapping migration as recorded by the Bureau of the Census for the 48 conterminous states of the United States from 1975 to 1980.

Dynamic reconstruction of the orophanryngeal swallow using computer based animation

The oropharyngeal swallow was modeled with computer based animation using data from biplane videofluorographic and dynamic CT images of 10 ml liquid swallows of a volunteer subject. Tracings of oropharyngeal structures from synchronized, magnification adjusted, images of the posterior-anterior, lateral, and cross-sectional planes were aligned in three dimensions with graphics animation software. Twenty oropharyngeal configurations were created at 1 15 second intervals to dynamically illustrate the swallow. These three-dimensional reconfigurations could be sequenced into an animation routine. Software analysis of the model permitted quantification of structural movement and intrapharyngeal volume across time. Such analyses can be used to detail both the efficacy of individual functional elements of the swallow as well as global pump function. It is hoped that modeling the oropharyngeal swallow will be useful to analyze mechanisms of dysphagia and the mechanics of compensatory therapeutic strategies.

Instructional animations: The in-house production of biology software

STUDENTS OFTEN have trouble conceptualizing certain phenomena in science. Traditional instructional media such as static illustrations, text, or video can be supplemented with computer animations in order to illuminate the concept for the learner. Some concepts must, by necessity, be depicted in this way in order to show processes or abstractions. The growing power of microcomputers and more user-friendly animation software have made in-house production of such animations a reality for the Iowa State University Biology program. Thirty scientific animations have been produced to date. This article explains how animations are developed from the conceptual drawing board to actual use in lecture halls and computer labs. Recommendations for the design, creation, and implementation of animations are outlined. Production is guided by practical technical considerations as well as instructional theory.