Forums Technical Discussion Resetting Object Rotation

Resetting Object Rotation

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jtk700cln
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49 posts
Joined: Jan. 2016
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Posted 5 hours ago
Hello all,

I am sending some geometry pieces back to the origin to do some manipulation. Im using a for loop, and within the loop Ive at least managed to move each piece back to the center. The issue is rotation. I want the objects existing normals “N” to be flush with the x axis while working, and the objects ‘up’ vector to be flush with Y axis {0,1,0}. I know I can use the arccos(dot(up, up2) function to get the angle I need, (and have done so), my issue is I cant figure out how to rotate the pieces accordingly.







So basically–object incorrectly rotated at center– its existing Normals should face towards +x {1,0,0}, and its “up” vector should face towards {0,1,0}.



After work is done, Id like to be able to send the piece back to where it came from, but am a bit stuck.



Thanks for the help!!!

Attachments:
rotation_reset_at_origin (1).hipnc (177.6 KB)

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davidderwin
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Joined: March 2013
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Using the VEX rotate function on a matrix will work to rotate around a given vector axis. I can't download your file at the moment but if you have a point or object at the origin then run this in a point wrangle:

@N = {1,0,0};
v@side = normalize(cross(@N,{0,1,0}));
v@up = normalize(cross(@side,@N));

float angle = 45;

matrix rot = ident();
rotate(rot, radians(angle), @side);

@N *= rot;
@up *= rot;
@side *= rot;
@P *= rot;

It will rotate however many degrees (45 degrees in this case) around the vector axis, which in the example above is @side ({0,0,1)}. It sounds like you have calculated the angles that each piece will need to be rotated so by using those angles and changing the vector axis as needed (rotating around x, y or z), this should be able to get your pieces rotated to the desired orientation.
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