mikekmx Posted July 28, 2014 Share Posted July 28, 2014 is the direction of rotation completely random? Quote Link to comment Share on other sites More sharing options...
Dadgad Posted July 29, 2014 Share Posted July 29, 2014 (edited) No, it is not. To determine the direction of rotation you must orient yourself at a positive point on the axis, facing towards the origin (0). As if you were in Plan looking down at your screen and doing a regular Rotate command on the Z access. For those who choose to use the define axis by 2 points method, this can become confusing, as the direction of rotation will be determined by the relative position, positive or negative, from the first point picked. I prefer using this in an isometric view, to be sure that everything is as you would want it to be. An old trick often used, is to position your right hand as if you were hitch hiking, and point your thumb in the positive direction along any given axis. Your fingers will curl in the positive direction of rotation for that axis. Edited July 29, 2014 by Dadgad Quote Link to comment Share on other sites More sharing options...
hoss Posted July 29, 2014 Share Posted July 29, 2014 The way I remember it imagine holding the axis that you are going to use with your right hand, with your thumb pointing towards the head of the arrow, positive rotation is the way your fingers folding Quote Link to comment Share on other sites More sharing options...
BIGAL Posted July 29, 2014 Share Posted July 29, 2014 Hoss maybe correct image is thumb up 1st finger full extend 2nd finger 1/2 extend so you get a XYZ axis physics about 40 years ago "Right hand rule" Mikekmx I only do real basic 3d but most times use the axis option even do twice, rotate3d X 90, I usually view in a 3d view so can see object as I rotate often undo and -90, use simple vpoint 1,1,1 to see. Using UCS OB can have un predictable results if object has 3d points of a XYZ plane. Quote Link to comment Share on other sites More sharing options...
mikekmx Posted July 29, 2014 Author Share Posted July 29, 2014 hand/thumb thing seems to work, thanks. Quote Link to comment Share on other sites More sharing options...
lrm Posted July 30, 2014 Share Posted July 30, 2014 In general most AutoCAD commands follow the Right Hand Rule (RHR). Point the thumb of your right hand in the direction the axis points and the curl of your right hand fingers define the positive rotation direction. 3DROTATE violates this convention for rotations about the y-axis! 3DROTATE uses RHR for the X and Z axis but a left hand convention for the y-axis. Go figure! I prefer ROTATE3D for keyboard specified rotations which always follows the RHR convention. Quote Link to comment Share on other sites More sharing options...
Dadgad Posted July 30, 2014 Share Posted July 30, 2014 In general most AutoCAD commands follow the Right Hand Rule (RHR). Point the thumb of your right hand in the direction the axis points and the curl of your right hand fingers define the positive rotation direction. 3DROTATE violates this convention for rotations about the y-axis! 3DROTATE uses RHR for the X and Z axis but a left hand convention for the y-axis. Go figure! I prefer ROTATE3D for keyboard specified rotations which always follows the RHR convention. That seems really strange. I have no use for the 3D Gizmo, so had never noticed that. I just checked, and you are correct, damn that is a bug if ever I saw one! Quote Link to comment Share on other sites More sharing options...
eldon Posted July 30, 2014 Share Posted July 30, 2014 In general most AutoCAD commands follow the Right Hand Rule (RHR). Point the thumb of your right hand in the direction the axis points and the curl of your right hand fingers define the positive rotation direction. 3DROTATE violates this convention for rotations about the y-axis! 3DROTATE uses RHR for the X and Z axis but a left hand convention for the y-axis. Go figure! That is very curious. I tried my Rotate3D, and it followed the RHR in X, Y and Z axes. Am I doing something wrong Quote Link to comment Share on other sites More sharing options...
lrm Posted July 31, 2014 Share Posted July 31, 2014 Rotate3d works fine. It's 3drotate that uses a left hand convention for rotations about the y axis. Quote Link to comment Share on other sites More sharing options...
Dadgad Posted July 31, 2014 Share Posted July 31, 2014 (edited) Rotate3d works fine. It's 3drotate that uses a left hand convention for rotations about the y axis. A bug is a bug, nothing more nor less. I have a hard time imagining what sort of explanation there might possibly be, if Autodesk were to claim it was intentional, and or, logical. Edited July 31, 2014 by Dadgad Quote Link to comment Share on other sites More sharing options...
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