Philip Crosby

Native Jack Files

Jack provides a powerful hierarchical modeling capability that allows you to import or build articulated figures. The hierarchy is a familiar inverted tree structure, with individual objects having parent and child relationships. This is a very effective way to define even complex systems of interconnected parts - such as the human body. The diagram below illustrates the hierarchy graphically:

Jack Modeling Hierarchy Environment

(Command: FileSaveScene)

At the highest level, systems are defined as scenes or environment structures. The environment is a collection of ―figures.‖ Each figure consists of one or more ―segments.‖ Segments in a figure are connected to each other by joints. In other words, a figure is an assembly of segments.

More importantly, the environment contains information required to regenerate a particular scene (for example: relative locations between figures, joint positions, size, and other constraints). These files have the extension .env.

.env files contain:

 References to Figure Files (.fig) and Segment Files (.pss) - Figure and Segment Files can also be embedded in the

.env file

 Relative Locations of the Figures

 Joint Angles/Positions

 Geometry Scaling

 Constraints and Attachment Information

.env files are also stored as ASCII text and can be opened/edited in a text editor. Environment files can reference the .fig and .pss files.

This allows the user to reference one .fig or .pss file multiple times in the same environment file or in multiple environment files. This can help reduce the overall size of files associated with a given project. This is also useful if a figure is modified. If you would like to have that modified figure in every environment file in which it is referenced, replacing the old .fig file with the new .fig file will automatically make the changes to the files that reference that .fig file. This is also applicable to .pss files referenced in an .env file.

If changes are made to the figure that occur more than once in an environment or a figure that is used in multiple environments, you will need to save the .fig file when prompted. If you do not save changes to the figure, the .fig file will be written to the .env file.

Therefore, if you don‘t save the figure, the .fig file will be embedded in the .env file. Other .env files cannot reference .fig files that are embedded in an .env file. To create a .fig file from a figure embedded in an .env file, simply open the .env file and save the figure. If you resave the environment, the .fig file will be referenced in the .env file. The .fig file will no longer be embedded in the .env file.

It is a good idea to save the .fig file after you make any changes or before saving the .env file. This is only necessary if you modify the figure. If you have already saved changes to a .fig file, you will not be prompted to save the figure when you save the .env file. Note if you change visibility this will flag Jack to prompt you to save the .fig file when you save the .env file. If you say yes, the visibility changes will be written to the .fig file. If you say no, the visibility changes will be written to the .env file.

It is important to understand what is not saved in an environment file. Reflections, view cones, skeletons, traces, ghosts, projections, and support glyphs are not saved with the .env file.

Note: An Environment File (.env) includes all the information required to recreate a scene. It contains information defining relative locations between figures, joint positions, size, and other constraints.

Figures

(Command: FileSaveFigures)

Figures are a collection of one or more segments, as well as any associated sites, colors, and joints. This data is stored in a Figure (.fig) file. Figure files contain references to segment files (.pss), sites, material properties, and joint connections.

.fig files are also stored as ASCII text and can be opened/edited in a text editor. Figure files can reference the .pss files. This allows the user to reference one .pss file multiple times in the same figure file or in multiple figure files. This can help reduce the overall size of files associated with a given project. This is also useful if the geometry is modified. If you would like to have that geometry modified in every figure file in which it is referenced, replacing the old .pss file with the new .pss file will automatically make the changes to the files that reference that .pss file.

If changes are made to the geometry, you will need to save the .pss file when prompted. If you do not save changes to the .pss file, Jack will use the last saved version of the .pss file. Therefore, if you don‘t save the .pss file you will lose any of the changes you have made to the geometry.

It is a good idea to save the .pss file after you make any changes to the geometry. This is only necessary if you modify the geometry. connections. (Joint connections and limits are retained when a figure file is saved. Joint angles information is not contained in a figure file.) Select the Include attributes check box to save attribute information (for example, color selections)

Segments

(Command: FileSavePsurf)

Segments make up the lowest level of the hierarchy. They consist of tessellated geometry data that makes up an object. This data is stored as ASCII text in a Psurf (polygon surface) file that can be opened with any text editor. This format is consequently easy to view and edit. These files have the extension .pss. Two sample

Psurf files are shown below in order to illustrate how segments are constructed.

Note: Remember the properties of the different file types.

A Psurf (.pss) file, also referred to as a segment file, only contains information defining a segment's geometry.

A Figure File (.fig) includes information about which segments make up the figure, sites, colors, and joints connections.

(Joint connections and limits are retained when a figure file is saved. Joint angles information is not contained in a figure file)

An Environment File (.env) includes all the information required to recreate a scene. It contains information defining relative locations between figures, joint positions, size, and other constraints.

Manipulations

(Command: FileSaveManipulations)

A scene or figure whose positions you want to use again later may be saved as an .env file. Select the Include Camera check box to save the coordinates of the current camera viewpoint coordinates.

Manipulations save the figure positions and joint angles. When loaded they allow you to reposition your loaded figures.

File Archiving

(Command: FileArchiveSave File to Archive)

The save file to archive feature allows users to a) save a file to a specified directory, b) save as one zip file, or c) both. Archive files are written out compressed, generally resulting in much smaller file sizes, especially when using psurf-only geometry.

Note: When saving your data to a directory, it is recommended that a new folder is created, to avoid overwriting data in a previously existing folder.

Save File to Archive Dialog

Import

(Command: FileImport)

Jack is intended to be used with other design and analysis software packages. Thus, geometry import and export capabilities are necessary to allow the transfer of data to and from Jack. Typically, you will bring geometry data for the scene to Jack from external sources, perform your analysis, then export geometry to downstream processes for further use.

Objects can be imported from CAD programs, opened from object libraries, or even created from basic CAD figures from within Jack.

Import Formats

Jack can directly open Vis (.jt) files and can import Vis (.jt), VRML 2.0 (.wrl), IGES(.igs, .iges), stereolithography (.stl), inventor (.iv), and optimizer (.csb) files directly. Command line translators are also available for these formats. In this chapter we will translate files from several of these formats. Translation can be accomplished from both the command line and directly from within the program.

Format File Extension

Import Formats for Texture Mapping & Visualization

Jack has the capability to use all of the above translators, and each has its own benefits and limitations. This section discusses the most commonly used translators and their features. Vis (.jt) files when opened directly will support textures, however when .jt files are imported into a scene the textures will be lost. VRML 2.0 is the only file format that will support textures when imported. The IGES 5.3 file format will import wireframe data.

Import Options

Several optimization and CAD options are available when importing data through the FILEIMPORT menu. In addition, basic scaling for certain file types is available and the object type output by the translator can be changed. You can control what type of file is output using the Jack Type option.

Jack type Output

Psurf 1 pss file

Figure 1 fig file and corresponding pss files Environment 1 env file and corresponding pss files

Note: JT files can also be directly opened within the Jack environment. No node-based operations, such as Snap To face or node, are available for directly opened JT files.

Functionality that allows the user to snap to a cursor point has been added to facilitate working with directly opened JT files.

JT Features

 Jack Version supports JT file versions through v10.

Benefits:

 Direct Load: Improves load time by factor of 10 in many cases;

Increases geometry handling capabilities including frame rate and size of files that can be loaded.

 Geometry should come in as it would in VMU (Appearance of JT geometry is much better that of same geometry imported using another format).

 Swapping: This will enable users to access all the functionality not available with JT. The context menu can be used to access this functionality. Turns visibility of JT segment off and replaces with psurf. Note that textures will not be maintained.

 Environment files referencing JT can be loaded into Jack and editing capabilities): Several features have been added in Jack to help compensate for this.

- Zoom to: Allows users to zoom into any geometry in the scene (including JT).The first piece of geometry in line with the cursor will be selected

- Snap to Cursor Point: Same behavior as above but works with move dialog.

 Collision detection is not supported with JT geometry: Use psurf swap to perform collision detection

 Joints created within a JT figure will not be maintained in VMU environment

 A single part of a .jt assembly cannot be loaded individually

 Segment highlighting may not work on all files

 Adjust Displacement: Can be used to move segments without creating a joint.

JT Export

Figures and scenes can be exports as JT. This option can be found under File -> Export -> JT.

Single Figure will export a selected figure as a single part.

Scene export will export all relevant figures in a scene as several parts of a monolithic .jt file

Notes:

-In v8.2, JT Export does not support materials (colors). Exported objects and figures will appear gray

-Texture mapping is not supported (ie, the psurf will export but without any texture)

-Export is NOT supported for: 6.0/6.1 smoothskin human figures, or JT figures

Translate Segment from JT

(Command: EditTranslate Segment from JT)

In order to translate a single part/segment of a JT file, select

―Translate segment from JT‖ either on the segment context sensitive menu or from the Edit menu. This option is also available from your segment context sensitive menu which is discussed in the next chapter. The original JT part will still exist but the visibility will be turned off. The translated part will constitute a separate figure, but is attached to the jt figure.

Functionality Psurfs JT

Translate to Native Jack ● ●

Display Assembly Hierarchy - ●

Reroot Figure or Assembly ● ●

Rejoint Segments or Parts ●

-Move Figure or Assembly by Site ● ●

Move Figure or Assembly by Vertex ●

-Attach Figure To ● ●

Joint Psurf Segment to Figure or Assembly ●

-Joint Figures or Assemblies Together ●

-Edit Materials ●

-Texture Map ● Only in TcVis

Edit Geometry ●

-Create in Jack ●

-Trace, Ghost, or Create Swept Volume ●

-Export to VRML or IGES ●

-Re-root Geometry Center

Sometimes geometry is loaded into Jack in an undesirable location, or with a root site that is offset from the geometry center. To help alleviate some of the problems associated with unwanted JT loading parameters, the default method of JT loading has been updated so the geometry center is re-rooted upon load. That is, when a JT file is loaded, a new root site called "root_override" is created and placed at the center of the figure's bounding box.

This feature is particularly useful for JT geometry that is defined far from the origin. After centering the root the geometry can be

moved/snapped to the desired location, rotated around its axes using the arrow keys, etc. This also makes it much easier to use these objects in TSB.

This option is enabled by default. To disable, go to Edit-> System Defaults-> JT Options and uncheck Re-root to Geometry Center.

This feature does not apply to JT files loaded as part of an

environment file, by design, to avoid disrupting entities in the scene (constraints, etc.). The "Center Figure Root" tool (described below) should be used for existing environments.

Center Figure Root Dialog

This tool was designed to assist users in rerooting a geometry center, in scenarios where the default JT load option (described above) does not apply. For example, imported (rather than directly loaded) JT data, as well as JTs loaded as part of an environment or TSB (.tsf) file can be rerooted using this option. Non-JT data, such as psurfs can also be rerooted.

This option is available via the main menu (Object –> Center Figure Root), or by right clicking on a piece of geometry in the Jack scene or Object Hierarchy.

Usage Details:

-The "root_override" site will be deleted if Undo is used after the command.

-If the command is invoked multiple times the "root_override" site will be moved - additional sites will not be added

Batch Translate Files

(Command: FileBatch Translate Files)

This command allows you to translate multiple files of the same format into Jack native (.pss) files. The translated files will be saved to the default home directory.

CAD Export

(Command: FileExport)

VRML or IGES output of a Jack scene is an option for generating 3-D version of you scene that you can share with others that don‘t have access to the Jack software. Jack can export individual figures or the entire Jack Scene.

Please note, the IGES and VRML translators are now considered to be legacy. While these are outdated, we have chosen to keep them available in order to support existing workflows. Please note that these translators are provided as is: we are no longer able to provide any updates to them. It is recommended that JT import/open and JT export be used to manage your data.

VRML Export

(Command: FileExportVRML 1.0)

Jack exports VRML 1.0. In both cases the segment definitions are preserved in the VRML format. Assembly information, however, is not saved.

VRML Export Dialog

IGES Export

(Command: FileExportIGES 5.3)

Jack also exports IGES 5.3. IGES export includes the option to save polygonal data as Bound Plane or Trim NURBS data.

Selecting the preserve hierarchy option will maintain segment definitions (parts).

IGES Export Dialog

Capturing Images

(Command: FileScreen Capture)

Much of a designer or engineer‘s job when using Jack is centered upon presenting analysis results for use in reports, design reviews, company intranets, documentation, and even marketing. This chapter will cover tools for creating high quality images, movies, reports, and presentations using Jack.

Screen Capture

Screen images can be generated easily and imported into other applications. They can be included in documents, presentation, e-mailed to colleagues and even placed on web sites.

Image Dialog Screen Capture

Notice that you have the choice of several different file types to save the image as. The options are slightly different for the Windows and UNIX versions of the software. It is important to specify the proper extension for the file type you select.

Rendering

Selecting the Rendered check box generates a multi-pass rendered image of the window. This will smooth jagged edges (anti-alias) in the window image. Rendered images will take longer to create because of the drawing process.

External Applications

There are cases where you may want to capture screen images interactively, including areas outside of the GRAPHICS WINDOW. You may want to capture the entire screen, including Jack‘s graphics, message, and command window or you may want to capture an image as you do something in Jack (e.g., to show the adjust joint or move glyphs during a manipulation).

Platform Command Result

Windows PrtScr Captures the entire screen Windows Alt + PrtScr Captures active window

SGI type snapshot in shell Starts SGI screen capture utility

Note: NVidia graphics cards may also demonstrate problems generating antialiased screen capture images - the resulting output images will not have antialiasing applied. This can be corrected by going in to the advanced graphics settings of the driver and setting

"Buffer Flipping Mode" to "Use block transfer". Be sure to quit Jack and restart after making this change. This is a persistent setting and will only need to be done once.

Chapter 2 Tutorial: File Management

This tutorial will introduce you to the Psurf, Figure, and Environment Files. You will also learn how to open files, import and export geometry, and how to capture images in Jack.

Exercise: Loading an Environment file

 Delete the Scene from EDIT>DELETE SCENE

Note: This command will delete all objects in your graphics window.

 Select the File Open icon

Note: The OPEN FILE DIALOG is a standard Windows format.

Open File Dialog

 Select the file Chapter2.env from the Training folder and hit the Open button.

This command will close the OPEN FILE DIALOG and load a previously saved environment into your graphics window. Your graphics window should look similar to the following.

Chapter_2.env

 Move the cursor over the human figure and the boxes (do not select anything).

Note: The message window content changes when positioned over the cubes or the human figure.

Exercise: Saving Figures and Segments

 Open barrel.fig (this is a figure file)

 Save the segment barrel FILE>SAVE>PSURF. Select Save Segment PSURFS.

 Select the barrel as the segment you are saving and select OK.

 Name the barrel segment newbarrel.pss

 Open newbarrel.pss. OPEN>FIGURE>NEWBARREL.PSS

Note: The barrel.fig file saved material colors. Figures save scale and color; segments (or PSURFS) do not save color.

 Add more barrels to your scene, and stack them in a corner.

 Save your changes by saving the scene/environment (Name your scene MYChapter 2.env) FILE>SAVE>SCENE.

 Exercise: JT Open and JT Import

 Delete the sceneEDIT->DELETESCENE and select the FILE->OPEN option

 Choose the file Jack_Cell4.jt from the folder. .

 Select Open

 Notice the JT file of a workcell comes in rotated about Jack‘s grid.

Jack_Cell3.jt when OPENED

Jack_Cell3.jt when OPENED

In document Modelo para el mejoramiento de la calidad y productividad en el área de armado en Dish México. (página 30-40)