File and Edit Menus (cont.)

Figure 2.66 Reading in a 3D object

The following parameters can be specified when reading in a file:

Table 2.7 Parameters when reading in a file

Parameter	Type	Description
Filename		Specifies the pathname of the file to read. Filenames without extensions default to .obj, and the program notifies you when it cannot find a file with the name you supplied.
	Read All	Reads all objects in the specified directory of the file type specified in File Type.
	Select One	Displays a list of objects in the specified directory, and lets you pick one object to load.
	Select Several	Displays a list of objects in the specified directory, but lets you select several objects to load.
File Type		Determines what type of object is being read in.
	Geometry	N-Geometry's native format (and are given a .geo extension).
	dxf	AutoCAD format.
	obj	Wavefront format.
	asf	Acclaim format (skeletons).
	bvh	BioVision format (skeletons).
	htr	Motion Analysis format (skeletons).
	All	Lists all file types in the object list.
Ignore Numbering		Specifies whether or not to pay attention to the internal numbering of an object file. The internal numbering is sequential, starting at 1 for each type of element, and is provided to make it easier for you to read the text file. Internal numbering is usually ignored to speed up read-in, but it might be advisable to turn off Ignore Numbering when you have hand-modified or have otherwise altered a saved object because the numbers no longer correspond to the positions of the modified elements in the listing.
Read body files		Specifies which body files are to be used when reading in an object.
	Newest	Uses the newest versions of all separately written body files.
	Recorded	Uses (possibly) older versions of body files that were current when the original object was saved.
	None	Skips reading any body files. Dummy or reinstanced bodies are substituted for the body files.
Body File Reread		Facilitates handling of binary body files already read into N-Geometry. Lets you specify the actions N-Geometry should take when it encounters an object that references a body that has already been read. This new menu item gives you a choice of five options:
	Reinstance	Reuses the existing body (this is the default).
	Make New	Makes a copy of the body. When the copy is saved, it is written to a different file.
	New, displacing	Makes a copy of the body and gives the copy the original filename. When the original body is saved, it is written to a different file.
	Revert	Re-reads the file and replaces all current instances of the body with the data on file.
	Revert if modified	Replaces all instances of the body with saved data only if the body has been modified; otherwise it acts like Reinstance.

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Save

• (CLICK-L) brings up the following menu:

Figure 2.67 Selecting objects to be saved

• Camera View saves either the current viewpoint or a previously saved view in a file. (See the section "Views," on page 5-4.) Viewpoints are read back in via Camera>Views.

  
  

• Light Groups saves currently configured light groups.

  
  

• Any or all brings up a multiple-value version of the same menu. Newly created and modified objects are highlighted. You can select or deselect any number of objects to save. On this menu, highlighting all objects means all objects will be saved to file. When you use Do It, N-Geometry saves the objects (without interrogation) into its own file, using the object's name and the default directory as a filename.

• (CLICK-R) automatically selects all loaded objects for saving to a file, using the object's name and the default directory as a filename; you can use the default filename or change it.

The save menu looks like this:

Figure 2.68 Saving objects

Table 2.8 Parameters for saving objects

Parameter	Type	Description
FILENAME		Specifies the name of the file to be written. N-Geometry now forces this name to be the same as that of the object. If necessary, N-Geometry replaces certain characters so that the filename is valid.
Object name		The name of the object. Changing this value renames the object and changes the filename.
Write-out units		The units in which the object's coordinates are saved. Changing this value scales the object coordinates correspondingly. The default is the current global unit.
Documentation		A brief description of the object, included at the beginning of the .obj file. This comes in handy when you write multiple versions of the same large file. You then need not load a file to find out which version it is; instead, type the following command at a LISP Listener: Show File <filename>
Separate body files?		Saves an object in N-Geometry format, and lets you choose one of four formats in which to save the object:
	No	Writes in the old style .obj format, writing one large ASCII text file for the entire object.
	Text	Writes one .obj file, plus a .body file and a .tbd file for each terminal object.
	Binary	Writes each body in binary format, creating .body and .bbd (binary body descriptor) files for each of the object's terminal objects. Saving objects in binary format creates smaller files that can be written and read faster. When you save an object in binary format, N-Geometry writes three types of files: one .obj file, plus a .body file and a .bbd file for each terminal object in the object group. A .body file is a short text file that contains the name of the flavor of the body, a list of the .obj files that refer to the body (multiple objects or versions can refer to a single body), and the versions of the body files that were current when the .obj file was written. By default, N-Geometry stores the .body, .bbd, and .tbd files in a directory called Bodies, which N-Geometry creates as a subdirectory of the directory where the objects are stored. For example, suppose you are restructuring two objects, cube and cube[2], into a new object named cube-group and stored in the /cube directory. N-Geometry stores the top-level object file, cube-group.obj, in the /cube directory but stores the .body and the .bbd files in /cube/bodies.
	History	If you turn the History option on, you save the sequential list of procedures that were used to get the object to its current state. If you read an object back in that was saved with history, you can use the Rebuild function to step through the rebuilding process. See the section "Rebuild," on page 2-64 for more information.
Number elements?	(for Text format only)	If selected, writes the number for each element as part of the file.
Faces by vertex?	(for Text format only)	If selected, write vertex numbers for each face on the object as part of the file.

The various parameters on the Save dialog are described in the table below:

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Export

Figure 2.69 The Export menu

Note. Not all formats support all the functionality of geometry's native format.

For example, if your object has displacements or GL Shade parameters assigned to it, it must be saved in N-Geometry's native .geo format with the File>Save command. Non-native formats do not support these features.

• (CLICK-L) or (CLICK-M) to export a single object
• (CLICK-R) to select several objects to export

Each of these formats is described in the sections below.

Exporting AutoCAD DXF

Figure 2.70 Saving an object in AutoCAD DXF format

Exporting Wavefront OBJ

Figure 2.71 Saving an object in Wavefront OBJ format

Exporting Acclaim Skeletons

Figure 2.72 Saving a skeleton in Acclaim format

Exporting Biovision Skeletons

Figure 2.73 Saving a skeleton in Biovision format

Exporting HTR Skeletons

Figure 2.74 Saving a skeleton in HTR format

Exporting Sony RSD

Figure 2.75 Saving an object in Sony's RSD format

For more information on the Sony RSD format, refer to the PlayStation Express User's Guide.

Exporting Nintendo 64

Figure 2.76 Saving an object in Sony's RSD format

For more information on the Nintendo format, refer to the Nintendo Express User's Guide.

Exporting Sega SGL

Figure 2.77 Saving an object in Sega's SGL format

For more information on the Sega SGL format, refer to the Sega Express User's Guide.

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Get

Figure 2.78 The Get Object menu

Since you normally create and modify objects entirely within the N-Geometry environment, you probably will not select this menu item.

Note. You'll need to use this only if you're familiar with LISP environment and want to create custom objects.

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The Edit Menu

• Make one or more copies of an existing object (using several techniques)
• Edit the body of an object (selected from an object list)
• Edit an object (selected from an object list)
• Deleting an object from N-Geometry

The GeoMenus>Edit menu looks like this:

Figure 2.1 The Edit menu

Each of the options on the File menu are described in the following sections.

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Copy

• (CLICK-L) physically copies the geometry of an object, creating a single discrete new object in the same location as the original. The duplicate is named "Copy of Object" where "Object" is the name of the original.
• (CLICK-R) on Copy displays the following options for adding objects to N-Geometry:

Figure 2.2 Other copy options

Each of these options is described below.

Reinstance

(CLICK-R) on Copy to reinstance an object.

• If you modify the body of the original polyhedron, that change is reflected in all the instances of that object-for example, if you extrude a face on the original polyhedron, all reinstances that share that body will have the same extruded face.
• If you select the object, the original and reinstances can be transformed independently.

Figure 2.3 shows a cube that was copied once and reinstanced once. Only the reinstanced cube reflects the modification to the original.

To create multiple reinstances of an object, see the Multiply section below.

Note. Why Reinstance? Reinstancing objects takes considerably less memory than copying, since only one body is shared by multiple objects. If you're working on a very complex scene, you may want to consider using reinstanced objects.

Figure 2.3 Left, copied and reinstanced cube; right, only reinstanced cube is affected by body modification

Multiply

Multiply either copies or reinstances a specified object; the positions of the copies or instances are based on the input you provide through the following dialog box:

Figure 2.4 Multiply dialog box

The following parameters can be specified when generating a grid:

Table 2.1 Multiply parameters

Parameter	Type	Description
Object to multiply		The object to be copied
Duplicate how		Method is used to duplicate the original (selected from the options described below).
	Reinstance-Copy	Makes a copy of original, then reinstances that copy so the original object can be modified without affecting the generated lattice.
	Copy	Makes copies of the original.
	Reinstance	Makes new instances of the original.
Arrangement mode		Layout of the new objects
	Linear	Positions the copies in a single row (along the x axis).
	Planar	Positions the copies along the x and y planes.
	Cubical	Positions the copies along the x, y, and z planes.
	Helical	Positions the copies along a helix (like a bed spring) of the specified dimensions. Radius specifies the radius of the helix. Pitch specifies the angle of the helix. Instances per rev sets the number of duplicates that appear on each revolution of the helix. Revolutions specifies how many times the helix wraps around its own axis.
	Per vertex	Positions the copies along the vertices of a specified object. (So, for example, four smaller cubes could be created on the corner of a larger cube.)
Number of copies		The number of duplicate objects to create. If more than one value is specified, enter the number of duplicates to create along each axis (x, y, and z).
Spacing mode		How the copies are spaced.
	Abutting	Puts the amount of space specified in Interobject spacing between the edges of adjacent generated objects.
	On centers	Puts the amount of space specified in Object centers between the centers of adjacent generated objects.
Randomize		Controls "randomizing" effects used when generating multiplied objects.
	Density	Number of objects are created along the specified path or lattice. For example, if you selected Linear for arrangement mode, 10 for Number of copies, and .5 for Density, only five duplicates would be created. (A smaller or larger number would produce a lower or higher density of coverage.) The duplicates would appear in random positions along the imaginary lattice.
	Position	Jogs the position of the duplicates, giving the generated pattern a more random appearance. For example, if you created multiple copies of a cube using a linear arrangement and specified a position value of 10, each duplicate could be +/-5 units from its "default" position. Note. Because you can specify position values for each of the x, y, and z planes, you can get cubical effects even if you choose a planar arrangement.
	Rotation	Similar to Position, except that it specifies rotational limits for each duplicate. A higher value allows more rotation; you can specify the range of rotation for duplicates along the x, y, and z axes independently.
	Scale	Scales generated duplicates, using scaling factors between 0 and the specified value. The higher the value, the larger the maximum size. Scale can be specified independently in the x, y, and z plane.
	Stretch	Stretches generated duplicates, using stretching factors between 0 and the specified value. The higher the value, the more "stretch" allowed. Stretch can be specified independently in the x, y, and z plane.

Figure 2.5 shows the results of multiplying a cube using planar arrangement mode, with six copies in the x direction and four in the y, with randomized rotation limits of 45, 45, and 45, and a randomized scale of 2.0:

Figure 2.5 Multiplied copies of a single cube using planar copy

Note. Copies of the object are positioned based on the orientation of the
original object.

Note. The generated duplicates are grouped together as one object in the object hierarchy; (CLICK-R) on an object in the object list to view its inferiors.

Also refer to the N-Geometry Tutorial for several examples of using Multiply to create other, more complex objects.

Rebuild

Figure 2.6 The Rebuild menu

• Object lets you specify the object to rebuild. (CLICK-L) on the text edit box to display a list of currently loaded objects and select the terminal object you want to rebuild.
• Step through specifies whether the recreation takes place one step at a time, or all at once.

If you set the Step through option to Yes when you (CLICK-L) on Rebuild, a second, smaller dialog box appears:

Figure 2.7 Stepping through the rebuild process

(CLICK-L) on Do It to execute each step performed to build the selected object, and (CLICK-L) on Stop when you're done. In the list of objects, the rebuilt object appears as "Rebuilt Object" (where "Object" is the name of the original object).

Note. You may find it helpful to turn the visibility of the original object off so that it doesn't interfere with your view of the new object as it is being rebuilt.

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Edit Body

To edit the body of an object:

1. (CLICK-L) on Edit Body.

An object list appears, displaying any objects currently loaded into N-Geometry.

2. Select the object from the object list that appears.

The body modification menu for the selected type of object is displayed.

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Edit Object

To edit the body of an object:

1. (CLICK-L) on Edit Body.

An object list appears, displaying any objects currently loaded into N-Geometry.

2. Select the object from the object list that appears.

The body modification menu for the selected type of object is displayed.

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Delete

• (CLICK-L) presents a list of objects from which you may select an object to kill.

Any or All lets you kill all or several items at once (basically the same as using (CLICK-R). If the object is a multiple-object group, (CLICK-L) on the object to delete all objects that make up the top-level object. (CLICK-R) on a multiple object group to display that object's hierarchy and select subobjects to delete.

• (CLICK-M) rescues the last item you deleted.
• (CLICK-R) lets you select multiple objects to delete at once.

Copyright © 1996, Nichimen Graphics Corporation. All rights reserved.