Three.JS rotate projection so that the y axis becomes the z-axis

Question

Traditionally, in 3D projections, the Y-axis is the axis that represents "up and down". I learned to think of it, with other engines, as that axis being the Z-axis. What I was wondering was whether there is a way in Three.JS to make the Z-axis the "up/down" axis. If so, are there any consequences to it?

Here is a diagram of what I want: enter image description here

To me it seems the picture on the right has "x" and "y" in wrong positions. Shouldn't they be swapped? — Arman
Could you point me to where I could read more about this convention? I've never faced it :-/ — Kuba

jterrace jterrace · Accepted Answer · 2011-12-05T20:20:45

You could just change the camera rather than the entire coordinate system. For example:

var WIDTH = 1024;
var HEIGHT = 768;
var VIEW_ANGLE = 45;
var ASPECT = WIDTH / HEIGHT;
var NEAR = 0.1;
var FAR = 10000;
camera = new THREE.PerspectiveCamera(VIEW_ANGLE, ASPECT, NEAR, FAR);
camera.position.z = 300;
camera.up = new THREE.Vector3( 0, 0, 1 );
scene.add(camera);

This changes the up vector for the camera to use Z-UP.

EDIT:

To illustrate an example, here's the jsfiddle you created slightly modified to call lookAt after setting the up vector: http://jsfiddle.net/NycWc/1/

Three.JS rotate projection so that the y axis becomes the z-axis

4 Answers