HANIME

An H-Anim Compliant Avatar Editor for NVEs

Christos Bouras

1,2

, K. Kartsakalis

, V. Triglianos

and Th. Tsiatsos

Research Academic Computer Technology Institute (CTI), Greece

Computer Engineering and Informatics Department (CEID), University of Patras

University Campus, GR 26504, Patras, Greece

Department of Informatics, Aristotle University of Thessaloniki, University Campus, GR 26504, Thessaloniki, Greece

Keywords: H-Anim, Graphical User Interface, Networked Virtual Environments, VRML, X3D.

Abstract: This paper addresses the problem of a visual H-Anim avatar editor. Although H-Anim is a very promising

standard for interchangeable avatars and avatar’s animation, the lack of an effective yet simple to use visual

avatar editor could repel users from H-Anim compliant Networked Virtual Environments. Therefore this

paper presents an H-Anim compliant editor, called HanimE, for creating avatars for Networked Virtual

Environments. This editor is entirely based on a graphical user interface and allows users to customize H-

Anim avatars, in a simple yet effective manner. The avatars created by HanimE can be integrated in various

H-Anim compliant Networked Virtual Environments regardless of the technology they are built on, since

they are X3D files.

1 INTRODUCTION

The popularity of Networked Virtual Environments

(NVE’s) has rendered them as part of everyday life

for many online users. Online users are represented

by avatars in the virtual worlds (Singhal & Zyda,

1999). These avatars, in most cases, are three

dimensional (3d) representations of a human like

model. Users tend to develop a psychological bond

with their avatars. One of the main tasks in an NVE

is the integration of humanoid avatars augmented

with humanoid animations. This could be useful for

the users to transfer their avatars from one NVE to

another. In many types of NVEs, such as Massively

Multi-User Online Role-Playing Games, users are

able to control and change the appearance of their

avatars (Yee, 2006). Usually, the users exploit this

functionality to customize their avatars in order to

reflect their real or virtual personality. The virtual

characters are starting to be widely used in user

interfaces in order to improve the human–computer

communication (Del Puy Carretero et al., 2005).

The creation of virtual humans that are

compatible with many different NVE platforms is a

challenging task, since the creation of humanoid

animation is a complex task, which usually requires

particular skills and training (Buttussi et al., 2006).

To that direction the H-Anim specification is

proposed. H-Anim is now included in X3D standard,

and it describes humanoids as an hierarchically

organized set of nodes. The contribution of this

paper is a multi-platform Java based H-Anim

compliant editor for modifying the appearance of

avatars. This editor is called HanimE (H-anim avatar

Editor). H-Anim specification is by definition geared

towards flexibility, compatibility and simplicity.

However, the variety of the available VRML/X3D

editors, are not suitable for non-experienced users

concerning the creation of humanoid avatars. Users

who have limited knowledge about the fundamental

concepts behind x3d (such as the usage of “nodes”

and “routes” as well as the definition of geometries)

cannot easily create H-Anim avatars. Most

frameworks available are either geared towards the

experienced 3d artist exploring the capabilities of

VRML, or they support the H-Anim avatars creation

by offering tools for developing animation and

simulation of movement. Either way, this makes

things complex and discouraging for the average

user who is seeking a graphical tool to modify the

visual properties of his/her avatar, such as colors,

skins and virtual items, before importing it to the

NVE of his/her choice. Given the limited number of

H-Anim compliant avatars, the creation of new

347

Bouras C., Kartsakalis K., Triglianos V. and Tsiatsos T. (2010).

HANIME - An H-Anim Compliant Avatar Editor for NVEs.

In Proceedings of the International Conference on Computer Graphics Theory and Applications, pages 347-352

DOI: 10.5220/0002825203470352

 SciTePress

avatars is a strenuous activity which requires hours

of work even for the experienced 3d artist. This is a

limitation in the broad adoption of H-Anim

specification. Furthermore, there is a significant

number of NVE communities that are not providing

a large number of available avatars to their potential

users. For example open source or research projects

cannot afford to hire 3d designers for this task. This

discourages users from participating to such a

community since users want to project their

individuality through their avatar in a virtual world.

A convenient solution to this problem is to provide

one type of avatar that can be customized in a

graphical user interface by the users according to the

his/her preferences. This solution not only saves

resources, but it also allows users differentiate their

avatars.

This paper is structured as follows. The next

section presents similar tools. Next we are

describing the main design characteristics of

HanimE and the functionality it offers. Afterwards,

we are presenting implementation and

interoperability issues and the way we have faced

them. Finally, some concluding remarks and planned

next steps are briefly described.

2 RELATED WORK

Most of the tools for visual H-Anim avatar editing

are either focused to specific tasks or complicated

for the average user. On the one hand this restricts

their integration to NVEs. On the other hand, it

discourages the average user from using them. Wang

and Ressler (2007) present a tool for viewing and

manipulating CAESAR (Civilian American and

European Surface Anthropometry Resource)

generated bodies. However, this work does not apply

to the average user neither from the perspective of

functionality nor from the perspective of ease of use.

Cobo and Biery (2002) presented a Web3D

toolbox for creating H-Anim compatible actors. The

toolbox supports avatar modelling through

primitives, meshes and NURBS, joint and facial

animation. It relies on Shout3D, which is a

proprietary and commercial platform for the

visualization of the avatars. This limits its portability

and ease of integration to NVEs. In addition it

requires that the user has 3D modeling skills and

intermediate knowledge of the H-Anim standard, in

order to use it effectively. HanimE editor presented

in this paper differs in two ways. First of all, it is

based on non-proprietary plug-ins, which allows

easy integration to third party platforms. Secondly, it

is crafted in a way that the basic avatar processing

tasks are performed in a way that no H-Anim

specific knowledge is required from the user.

3 MOTIVATION AND

RATIONALE

Our solution aims at bridging the gap between the

user’s demands for simple avatars creation and the

compatibility with H-anim standard. For that reason

we have implemented HanimE, that is offering to the

avatar creators a graphical interface to create their

avatars. All the editing takes place on a purely visual

level, providing the user with all the sufficient

graphical tools required so that s/he can see any

change on his avatar instantly. Possible changes

include the change of the color of avatar’s shoes, the

exact fitting of sun glasses on the avatar’s head, or

the complete replacement of a body part with a new

one. Any coding and/or technical issue concerning

H-anim compatibility is transparent to the users.

HanimE supports the following features:

• Automatic or manual H-Anim avatar loading.

• Manipulation of the Material Node properties

such as colour, transparency etc.

• Automatic or manual H-Anim avatar scaling.

• H-Anim avatar rotation.

• Texture mapping.

• Virtual items library.

• Adding and adjusting size and orientation of

virtual items on an avatar.

• Save X3D Scene to file.

HanimE is organized in three parts: (a) a

visualizer; (b) library containing virtual items/ H-

Anim body parts; and (c) a material node editor.

This organization aims in guiding the user to the

desired result through simple steps that are easy to

follow.

The visualizer is the first user interface screen

that appears when H-AnimE is launched. An avatar

can be loaded both automatically or manually.

Finally, from that screen a user can save his/her

avatar. The visualizer is an extended VRML/X3D

browser window that deals with the tasks of loading

an avatar, visualizing it and exporting it to a file. In

addition this window triggers the virtual items/ H-

anim body parts library window and/or the material

node editor. The loading portion is accomplished by

a custom fully featured X3D/VRML parser. This

parser enumerates various aspects of an VRML/X3D

file such as characters, lines H-Anim Joints,

Segments Humanoids, Displaces and Sites.

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Moreover, it calculates the Level of Articulation of

an avatar as well as whether it is H-Anim compliant

or not. Additional features include the VRML

version of the file, syntax errors check, ROUTEs

and PROTOs syntax check, Segments to Joints ratio

check, orphan Joints check etc. When a user wants

to add geometry to an avatar, either in the form of an

item/accessory or in the form of an H-Anim

compliant body part, the aforementioned library is

triggered. In cases where the user needs to modify

existing geometry, the material node editor is

invoked.

The virtual items/ H-Anim body parts library

is a library that hosts both virtual items, such as hats,

sunglasses etc., and H-Anim compliant body parts,

for example arms and legs. These can be imported,

scaled, transformed and adjusted to an avatar. This

library features both integrated and user added

items. Users can add and instantly preview items to

the library, from ordinary VRML/X3D files. As long

as they have selected the items they want to import,

these items are imported to the 3D scene that

visualizes the avatar. Subsequently, the material

node editor is launched to adjust the properties of the

items or modify the avatar.

The material node editor consists of three

panes. The first pane is a 3D previewer in which the

user previews the changes on the avatar during the

editing. The second pane holds a visual

representation of the avatars joints, where each joint

is represented by a small circle. Users can specify

the joint that they like the item to bind to. The

selected joint is highlighted and the item is bound to

the selected joint, resulting in smooth item motion

when the joint is animated. Finally, the last

component is a tabbed pane that allows the users to

adjust the position, the color and the texture

properties of an avatar or a virtual item. These

actions are performed in a visual way using

graphical controllers. Furthermore, the user can

enter a numerical value for the field s/he is

changing, e.g. the diffuse color of a material.

In addition, in order to ensure portability, the

editor is written in Java (and thus platform

independent) and the processed avatar can be

exported as an X3D or VRML file. Both

characteristics allow the migration of the user’s

avatars to his/her favourite H-Anim compliant NVE

platform.

Figure 1: Main screen with automatic avatar loading.

4 AVATAR EDITING PROCESS

This section describes the avatar editing process.

The function of the utility presupposes the existence

of a VRML file that contains a valid H-Anim avatar,

structured according to the H-Anim 1.1

specification, with the list of Joints named according

to the full description of the specification. We also

presuppose that available to the user is a long list of

items written in VRML, each one contained in it’s

own VRML library, although that is not strictly

necessary for the editor to function.

The operations supported by the editor on the

avatar are: material editing, item/ body part fitting.

As far as materials are concerned users can modify

material properties such as color and transparency.

Item/body part fitting describes the process of

loading items or body parts to the Avatar Scene,

selecting the Joint to which they will be attached and

relocating them correctly so that they fit in the scene

accordingly. The operation of the editor is based on

the steps depicted in Figure 2.

Step 1: Avatar Loading. User loads the avatar on

the startup editor screen, either manually, or by

setting the editor to automatically load the avatar

each time s/he launches the editor (Figure 1).

Step 2: Selection of Editing Function. The user

chooses the editing function (a) import of an item or

a body part to the avatar, or (b) editing the material

nodes of the avatar. In the second case, steps 3 and 4

are omitted and the editor goes straight to step 5.

Step 3: Selecting Items from Virtual Items

Library. User is shown the library of available

items and body parts (Figure 3).

This library contains personal items/body parts

for each user. Each user can fully manage this

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349

Figure 2: Mechanism Flow chart.

Figure 3: Virtual Items and Body Parts Library.

library by adding new items, body parts, removing

old ones and/or selecting/viewing the items s/he

wishes to import. This has to be a collection of non

H-Anim files.

Step 4: Importing Items from Items Library.

User imports selected items/body parts to his/her H-

Anim avatar. Both the avatar and the imported

items/body parts appear on the next screen (the edit

screen,

Figure 5 and Figure 6), with the item given a

set of tools for relocation on the X, Y, Z axis,

scaling or rotation.

Figure 4: Changing Colors.

Step 5: Editing the Material Nodes of the Avatar.

The edit screen contains a view of the Scene (the H-

Anim avatar, along with the imported items, if any),

and a panel showing the H-Anim Joint Hierarchy. In

this panel, the Joints used by the avatar are

highlighted and selectable. Below this panel is a set

of tools by which the user can modify the material

properties of any selectable (highlighted) Joint.

Figure 5: Adjusting a helmet to an avatar.

These tools appear as part of the “Colour” tab

(Figure 4) of this area, and allow the changing of the

material attributes: diffusion color field,

transparency, shininess etc. Any changes occurring

to the material appear instantly on the Scene.

Step 6: Relocation of Items. The “Position” tab of

the same area is only enabled if user chose to import

an item on step 2, otherwise this panel is empty. The

list of tools for the relocation of the imported item is

provided here, as explained in step 4. It should be

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350

Figure 6: Adjusting a shoe to an avatar.

noted that the user must select the Joint to which the

item will be attached (e.g. a hat item would be

attached to a node corresponding to the head). The

editor provides the option for automatic relocation of

the item to match the coordinates of the selected

Joint. However, the user can take it one step further

using the relocation tools to fit his item exactly

where he wants it to be before attaching it to the

selected node. Once that happens, the item is

moving along with the rest of the H-Anim avatar,

following the corresponding ROUTEs of the Joint.

Step 7: Save/Export. The user can choose to save

the avatar’s file, or to export it to the NVE for which

the editor is to be used.

5 IMPLEMENTATION AND

INTEROPERABILITY ISSUES

One of the major goals of the editor is to be portable,

while complying to open and widely used standards.

In order to obtain portability the whole application is

programmed in Java that makes it executable on

virtually every platform for which a Java Virtual

Machine exists. The manipulation and visualization

of the X3D models was developed using the Xj3D

Toolkit, a Java base toolkit for X3D and VRML

content. However, the usage of Xj3D entailed some

problems.

One of the major issues with the use of the Xj3D

toolkit is the complete absence of an integrated

“Save Scene To File” function, that would take full

responsibility for extracting all the valuable data

from an X3DScene Object in Java and writing them

in the correct format in an output file. The solution

to this issue is a challenging one, considering the

fact that not all Nodes in an X3DScene are named,

and that the Xj3D package does not allow the user to

read values from certain field types, therefore

rendering the implementation of a “Save Scene to

File” function from scratch nearly impossible. Our

solution to this problem is based on the fact that the

user makes use of already existing X3D files, both

for the avatar and the items to be imported, which

can be parsed by Java and treated as simple text files

following the appropriate X3D format. When the

applications needs to save changes to the loaded file,

it opens up the loaded file using the tools contained

within the java.io.* package used for reading/writing

to a file as text. Subsequently the application scans

the file for the appropriate position(s) to save the

new data and carefully removes any old data that has

to be replaced, with the edited file being stored in

the same folder used by the utility and the original

file intact, only to be replaced with the new one

when the user clicks on either the “Save” or “Save

As” button.

The editor is designed to be used as a stand-alone

application for creating and editing avatars.

However, in case that the NVE designer chooses to

integrate HanimE to a NVE platform, the following

have to be considered: An NVE administrator

integrating HanimE to his NVE platform would have

to provide access to three screens either prior to the

importation of the user avatar to the NVE’s world,

or as an extra editor once the user is inside the NVE.

These three screens are the HanimE project Frames

(using javax.swing.JFrame): the startup screen, the

item library screen and the edit screen, which

connect with each other. In any case, the NVE can

read the edited H-Anim avatar with the new values

either directly, from the x3d Browser contained

within the startup and edit screens as an X3D Scene,

or by reading the corresponding saved filed after the

user has edited his avatar. In the latter case, the

editor automatically generates a backup VRML file

in the same folder as the editor, which can be used

as a direct reference.

6 CONCLUSIONS – FUTURE

WORK

An H-Anim compliant avatar editor was presented in

this paper. The focus of the authors is to provide a

portable easy to use graphical editor for avatar

customization, while at the same time comply with

the H-Anim specifications. The application is

developed upon portable and open standardized

technologies to allow platform migration, such as

HANIME - An H-Anim Compliant Avatar Editor for NVEs

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Java and Xj3D. It features a friendly easy to use

graphical interface that the average user can handle

with ease. The editor supports functions such as

adding H-Anim body parts and items to an avatar,

avatar rotation, changing colors and more, and can

save the prefered state of an avatar as an X3D file.

Furthermore, an VRML/X3D parser utility presents

useful information to the end user.

Among our future plans is the enhancement of

the editor with new features. More specifically, we

intend to integrate the work presented in Bouras et

al. (2009) that will make possible the addition of H-

Anim animations to the user’s avatar. Moreover, an

animation authoring tool will provide animating

capabilities to the average user. A user will be able

to add, remove and adjust animations to an avatar, as

well as to create custom animations through a visual

wizard. Furthermore, an avatar creator tool that will

allow the creation of custom avatars is to be

integrated to the next version. The tool will follow

the same principles HanimE follows, that is

efficiency combined with ease of use. The user will

have a set of primitives and body parts that he will

be able to modify and combine in order to form

his/her avatar. Finally, to improve H-Anim

interoperability, an H-Anim syntax validation and

correction tool will be incorporated to the editor. It

will parse VRML/X3D files imported by the user

and it will validate them against the H-Anim

standard. In case that the file has errors or

incompatibilities with the H-Anim standard, the tool

will try to repair the file or will suggest solutions to

fix the problems. We believe that the above

enhancements will offer a powerful tool to the

average user and will enforce the position of the H-

Anim standard, eliminating some of the difficulties

that prevent it from being widely spread.

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