First off, both OpenSceneGraph (OSG for short) and Ogre3D are very well documented, supported, large forum etc… I don’t know much about Irrlicht besides it’s the newest of them. You probably won’t go wrong with either of the first two. Someone mentioned CrystalSpace; I haven’t looked at that in years, but it was far behind … Read more
There are many possible camera positions + orientations where the bounding box would fit inside the view frustum. But any procedure would select one specific camera position and orientation. If you would consider bounding spheres, one solution could be to first change orientation to look at bounding sphere center then move back sufficiently (negative look … Read more
http://en.wikipedia.org/wiki/Rotation_matrix. Look under the section Rotation matrix from axis and angle. For your convenience, here’s the matrix you need. It’s a bit hairy. theta is the angle, and ux, uy, and uz are the x, y, and z components of the normalized axis vector If you don’t understand matrices and vectors, post back and I’ll … Read more
If there are M lines of latitude (horizontal) and N lines of longitude (vertical), then put dots at (x, y, z) = (sin(Pi * m/M) cos(2Pi * n/N), sin(Pi * m/M) sin(2Pi * n/N), cos(Pi * m/M)) for each m in { 0, …, M } and n in { 0, …, N-1 } and … Read more
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, … Read more
Here is a Python example which finds the intersection of a line and a plane. Where the plane can be either a point and a normal, or a 4d vector (normal form), In the examples below (code for both is provided). Also note that this function calculates a value representing where the point is on … Read more
I’ve written for my project the following function; it receives an THREE.Object3D instance and a camera as a parameters and returns the position on the screen. function toScreenPosition(obj, camera) { var vector = new THREE.Vector3(); var widthHalf = 0.5*renderer.context.canvas.width; var heightHalf = 0.5*renderer.context.canvas.height; obj.updateMatrixWorld(); vector.setFromMatrixPosition(obj.matrixWorld); vector.project(camera); vector.x = ( vector.x * widthHalf ) + widthHalf; … Read more
Here is a single formula that avoids all the case logic. (I happen to be working in JS right now, so here’s a JS implementation). Let rect = {max:{x:_, y:_}, min:{x:_, y:_}} and p={x:_, y:_} function distance(rect, p) { var dx = Math.max(rect.min.x – p.x, 0, p.x – rect.max.x); var dy = Math.max(rect.min.y – p.y, … Read more
We have our own JSON Geometry format. You can use these: Editor (drag your object into the window, select it and select File/Export Geometry) Blender exporter Python script from OBJ to JSON
Triangles can never be non-planar; anything with more than 3 points can be non-planar and thus un-renderable unless converted to triangles. For example: A square is two triangles that are on the same plane, if all the points that make up the square are co-planar. It takes a lot of calculations to make sure all … Read more