# [request] jit.euler2quat & jit.quat2euler _ attribute for order of rotation

it seems that the order of rotation used in jit.euler2quat is YZX:

first X rot, second Z rot, third Y rot

so X is the bank (tilt) axe.

there is 12 rotation order possibilities.

A convenient order of rotation for openGL, when object is facing the camera is YXZ:

first Z rot, second X rot, third Y rot

It is more logical to use this order, respect to the direction and lookat attributes of jit.anim.node that use the Z axis of the object.

so Z is the bank (tilt) axe.

Could you create an attribute for those 2 objects like: rotation_order (default: yzx, yxz etc…)

or make an object like jit.eulerYXZ2quat and jit.quat2eulerYXZ

or perhaps send me or make the code public for jit.euler2quat & jit.quat2euler, so i can adapt them.

thanks

I created a mxj for this:

public final void yxz_r(double x, double y, double z) {

// Y : heading, X : attitude, Z : bank

// enter: XYZ _ order process: YXZ

// first Z rot, second X rot, third Y rot, for jitter conveniences

// Assuming the angles are in radians.

double sx = Math.sin(x/2);

double cx = Math.cos(x/2);

double sy = Math.sin(y/2);

double cy = Math.cos(y/2);

double sz = Math.sin(z/2);

double cz = Math.cos(z/2);

// R= Qx*Qz _ first Zrot then Xrot

// double Rx = cz*sx;

//double Ry = -sz*sx;

//double Rz = sz*cx;

//double Rw = cz*cx;

// R= Qy*Qxz first XZrot then Yrot

//qx = Rx*cy+Rz*sy;

//qy = Rw*sy+Ry*cy;

//qz = -Rx*sy+Rz*cy;

//qw = Rw*cy-Ry*sy;

// R= Qy*Qx*Qz first Zrot then Xrot then Yrot

qx = cz*sx*cy+sz*cx*sy;

qy = cz*cx*sy-sz*sx*cy;

qz = -cz*sx*sy+sz*cx*cy;

qw = cz*cx*cy+sz*sx*sy;

quat_out();

}

hello Spa.

i have logged a feature request for a rotation-order attribute to the quaternion objects.

our implementation is more or less derived from this website:

http://www.euclideanspace.com/maths/geometry/rotations/conversions/quaternionToEuler/

Thanks Robert.

Is it possible to have a code example of these objects, so i could use them as base for developing similar objects.

thanks

i’m not sure what you are asking.

the website i linked to has sample code.

your mxj code you posted should also work fine.

if you want to develop externals, the sdk is the place to start:

I just wanted the jit.euler2quat and jit.quat2euler source code …

mxj seems 4 times slower than native objects, due to bridge from max to java i suppose.

well, i suppose it was a bit short to include it in the 6.0.7 release.

Hope it will appear in the next one.

thanxs

with 6.1.3, jit.euler2quat and quat2euler have an attribute called @rotate_order, allowing you to specify the order rotations are applied.