Drawing Splines on 3D. Java Version

A project by

Rodolfo Cartas Ayala rodolfocartas@gmail.com

Submitted to

Dr. Raffaele de Amicis

January 8, 2007

User’s Manual Execution On Windows and Mac OS X double click the provided jar file. To launch from console, type java –jar curve2.jar The application requires Java 1.5 and Java 3D 1.31 installed. It also requires the colorchooser.jar and parallel_camera_parameters.jar files mapped in the system’s classpath. Both files are included in the distribution. The Toolbar Navigation/Selection Button When this mode is active, clicking on a curve will select it allowing further modifications. Clicking on the canvas allows you to navigate the scene. Rotation, zooming, and translation are done pressing different mouse buttons.

Left clicking rotates the scene.

Rotating the mouse wheel zooms in and out.

Right clicking translates the scene. Draw Button To draw, simply turn on this mode and click on the canvas. To finish drawing a curve, double click at the termination point. The curve properties can be changed using the properties panel.

Navigation/ Selection

Draw

Copy

Delete

Cut Parallel Perspective

Join Drawing Plane

Multiple selections can be done pressing the SHIFT key and clicking on each curve. Copy Button In this mode a copy of a curve is creating when clicking on it. Delete Button In this mode a curve is deleted from the scene when clicked. Cut Button A curve can be cut clicking on two points belonging to it. The clicked point will be shown. Join Button To join two curves with a hermite curve, click on the start and end of the curves to join. Parallel Perspective When clicked the canvas will show the scene using parallel perspective. Drawing plane When active and in drawing mode, this will show a plane where curves are drawn. The drawing plane can be modified using the following keys: T Shows a perpendicular plane to the current one. = Rotates the plane left.

- Rotates the plane right. The Properties Panel Curve Type Five types of curves are provided: Hermite Spline, Four Point Spline, Bezier Spline, Cubic B-Spline, and Cardinal Hermite Spline. The first two require four points to be drawn. The rest can be drawn with at least two points and up to twenty points. Thickness Selects the thickness of the curve. Color Select the color of a curve.

Curve Type

Thickness

Color

Modifying Curves Changing properties To change the properties of a curve just select it and then use the properties panel to change type, thickness, or color. Translating To rotate a curve first, select it and then right click on it. A contextual menu appears, click on the translate option. A green bounding box appears. To translate, keep pressed the mouse’s right button over the box and move it.

Rotating To rotate a curve first, select it and then right click on it. A contextual menu appears, click on the rotate option. A blue bounding box appears. To rotate, keep pressed the mouse’s left button over the box and move it.

Scaling To rotate a curve first, select it and then right click on it. A contextual menu appears, click on the translate option. A dialog appears, enter the scaling factor and click ok. Grouping To group a set of curve, multiple select them and then go to Selection>Grouping. When clicking on any of the curve a white box containing the curves will appear. Translation, Rotation, and Scaling can be applied to the group. To ungroup, select the group, and then go to Selection>Ungroup.

Saving and opening scenes Use the Open and Save options of the File Menu to save the scene to a file. Files are written in XML.

System Model Main Classes The following class diagram shows the core classes in the system. User input and scene graph management.

DrawingFrame: A Swing component used to capture the mouse wheel events. CurvesCanvas: Class inheriting from Canvas3D. This class manages the scene graph. Control: This class bridges widget events to the drawing subsystem through the Canvas. DrawingBehavior: Processes events to draw curves. It then creates CurveGroups that contain a Spline, the generalization of a Curve. This CurveGroups are added to the scene graph.

Spline Subsystem

The Spline abstract class implements functionality to manage geometries and callbacks to the Behavior Subsystem through the GraphicalSelectableObjectInterface. All classes inheriting from Spline must implement the calculation of points and other special functions such as cutting or derivative calculation. The CurveGroup inherits from BranchGroup and is used to store a Spline and behaviors that modify the Spline appeareance. Behavior Subsystem

CurvesPickBehavior accepts mouse events and picks the objects clicked. CurveClickerBehavior stores the last object clicked. DrawingBehavior gets the mouse event and creates Splines. JoinBehavior and CutBehavior use the object stores by their parent to implement curve joining and cutting. KeyboardBehavior process key presses to modify the drawing plane. ModeConstants is used to store constants for DrawingBehavior.