May 18th 2001 | Arena Reed

Expression 2 by Creature House

Expression 2 is a unique vector-based drawing application that allows you to create images with complex brush strokes, called Skeletal Strokes.

Once a Skeletal Stroke is applied to a drawn line it is altered based on length, curvature, colorization and pressure variation. The power of this is that a drawing can be manipulated globally by changing the Skeletal Stroke, or individual strokes can be changed or deleted.

It is possible to create beautiful natural looking drawings by using Skeletal Strokes of scanned brush strokes, which can be pixel-based or vector-based. It is also possible to obtain a wide variety of distortion effects by defining an image as a Skeletal Stroke and then applying it to a variety of lines with different pressure variation and colorization.

Image by Miyuki Hikita

It is not necessary to have a pressure sensitive tablet, but pressure sensitivity in combination with Skeltal Strokes is the best part. Once Expression's Skeletal Stroke content is customized to suite the the type of illustration it's being used for, it becomes even more powerful. Since the Expression's foundation is vector-based illustrations are scalable. The final file can be vector format file, or a pixel-based format of any resolution.

In this image the Skeletal Stroke on the left is applied to a variety of different lines on the right.

Export to Flash is supported in this latest release with some interesting animation features. It is possible to create a swf file in Expression complete with links, animation and mouseEvent effects. This is ideal for people who want to distribute vector based imagery or animation over the web without ever touching a timeline.

The swf file can also be imported into Flash where the graphics can then be used as part of a more complex project. A couple things to note are that animations and MouseEvent effects do not import into Flash. Since Flash does not support Skeletal Stroke technology, a complex image may be more optimized in a pixel-based format. For use with Flash, Expression is best used as a tool for creating natural looking imagery, variations of a complex form, or bold brush strokes.

326Kb sample file ( Huuuge file!)

Animating
Animation with Expression is not as easy as illustration. Skeletal Strokes can be based on other Skeletal Strokes and can have multiple views. Animation is achieved by treating the views of a Multi-view Skeletal Stroke as cels in an animation. In a multi-view stroke, new views are created by moving the points of the primary view, this makes animation a little tricky.

The best way to approach this type of animation is to start with simple shapes that contain points that are easy to modify. The little blue people in this animation were created by modifying shapes drawn with the B-spline tool, a tool that changes adjacent points based on an independent reference point. If the primary view is a complex curved shape created with the pen or brush tool, the editing of subsequent views can become a challenging maze of points and handles.

MouseEvent effects can be assigned to objects via the Objects palette. Double-clicking on an object calls up a dialog that has information about the object, through which you can click on a button that will bring up the Flash Settings dialog. The Flash Settings dialog is pretty straight-forward, allowing you to set behaviors for different mouseEvents (normal, over, and click). Motion behaviors include: Animation (if it is a multi-view stroke), Pulsate, Rock, Vibrate, Enlarge and Shrink. Color Effects include: Fade, Blink, Brighten and Darken. The Flash Settings can also be used to set links. The process is convoluted (dialogs within dialogs) and the result is hard to fine tune since the only way to see the result is to export to a swf file. This functionality is great if the end product is basically a vector-based image map with rollovers.

'the Moon' Sachiko Hongo

CreatureHouse is working on the release of an animation tool called LivingCels that will integrate Skeletal Stroke technology and key-frame animation. LivingCels will allow frames to contain different numbers of points unlike Expression. Check out some of the animations created with LivingCels on the Creature House web site and watch for its release, which promises to be very exciting for animators.

The way a flash developer would most likely use Expression is by creating vector or pixel based elements in Expression and then animating them with Flash. The advantage to this is that work created with Expression has a different look than art created with other programs. Objects can be imported into flash by copy-and-paste or by exporting a Flash file.

Image by Atsuko Sumiyoshi

Summary
Overall, Expression is a great program. It is not the perfect solution for creating Flash projects, but it's fun drawing tools make it worth trying. It is a unique program that offers a set of tools that are quite powerful. People who use Expression, love it.

These images were all created by artists who share their work and enthusiasm on the Expression User Page. There is a 30 free trial version of Expression on the Creature House web site at http://www.creaturehouse.com/