ObJS

ObJS

A 3D Wavefront obj file viewer for HTML5 written in JavaScript

Features

• Object rotation.
• Zoom in and out.
• Object movement.
• Mouse and touch control.
• Choose to draw (or not) vertizes, edges or faces.
• Use mtl files for material color.
• Change colors of background, vertizes, edges, and faces during runtime.
• Change face transparency during runtime, so hidden elements are visible.
• Change zoom and rotation speed during runtime.

How to use

Just include the ObJS.js in your project, create a ObJS object, and initalize its canvas.

myObJS = new ObJS();
myObJS.initCanvas(canvas);

• canvas is the canvas element in witch the model will be represented. If this parameter is not specified, the script will try to use a canvas called ObJSCanvas.

Then you can load any obj model by calling

myObJS.load(file);

• file is a character string with the path to the file, relative or absolute.

If you want to clear the canvas, just call

myObJS.clear();

Note that the canvas is automatically cleared when a new object is loaded.

Transformations

Rotate the object

You can rotate the object by dragging it with the mouse or your finger in a touch screen. Also, you can apply rotation programatically:

myObJS.rotateX(-1); //Rotate along the X edge to the left
myObJS.rotateX(1);  //Rotate along the X edge to the right
myObJS.rotateY(-1); //Rotate along the Y edge to the left
myObJS.rotateY(1);  //Rotate along the Y edge to the right

Note that the rotation speed can be set (see Set rotation speed).

Move the object

You can move the object around by dragging it with the mouse while holding down the shift key. Also, you can move it programatically:

myObJS.rotateX(-1); //Rotate along the X edge to the left
myObJS.rotateX(1);  //Rotate along the X edge to the right
myObJS.rotateY(-1); //Rotate along the Y edge to the left
myObJS.rotateY(1);  //Rotate along the Y edge to the right

Note that the rotation speed can be set (see Set movement speed).

Zoom

Zoom in and out can be achieven with the mouse wheel, by pinching the mode if you are using a touch screen, or programatically:

myObJS.zoom(value);

value can be any float number, positive to zoom in, and negative to zoom out. 1 and -1 are a one step zoom in or out. Note that the zoom speed can be set (see Set zoom speed).

Customization

You can change parameters such as the elements to draw, their color, transparency, rotation speed, zoom speed... in the script, but much of them can be changed on runtime, so you can use controls.

Select which elements to draw

myObJS.drawVertizes(true);    //Draw vertizes
myObJS.drawVertizes(false);   //Don't draw vertizes

myObJS.drawEdges(true);       //Draw edges
myObJS.drawEdges(false);      //Don't draw edges

myObJS.drawFaces(true);       //Draw faces
myObJS.drawFaces(false);      //Don't draw faces

myObJS.drawBackground(true);  //Draw the background
myObJS.drawBackground(false); //Don't draw the background

Select color for elements

myObJS.setVertizesColor(code);   //Set the color for the vertizes

myObJS.setEdgesColor(code);      //Set the color for the edges

myObJS.setFacesColor(code);      //Set the color for the faces

myObJS.setBackgroundColor(code); //Set the background color

• color is a hexadecimal triplet with the color code, including the number sign ('#'), and three or six hexadecimal characters. Valid examples are:
  • '#ff0000' for red.
  • '#f00' also for red.
  • '#FF8600', for orange.
  • '#DDFFDD', for light green.

Use materials

If a .mtl file is present in the same directory as the obj file, you can use the materials there to colorize the model (enabled by default).

myObJS.linkMaterial(true); //Use .mtl file
myObJS.linkMaterial(false); //Don't use .mtl file

Note that, when using .mtl files, faces with no material assigned will use the color defined by the user.

Select face transparency

myObJS.setAlpha(percent);

• percent is an integer, between 0 and 100, indicating the level of transparency you want to apply to the faces.

Set rotation speed

myObJS.setRotationSpeed(value);

• value is an integer, between 0 and 10. The greater it is, the greater the rotation speed.

Set movement speed

myObJS.setMovementSpeed(value);

• value is an integer, between 0 and 10. The greater it is, the greater the movement speed.

Set zoom speed

myObJS.setZoomSpeed(value);

• value is an integer, between 0 and 10. The greater it is, the greater the zoom speed.