Clockwise is negative

[Jeff Kemper]

rotation.

Anyone know the origine of this convention?

TIA

[Cuda84]

The Cartesian coordinate system was developed by the mathematician Descartes during an illness. As he lay in bed sick, he saw a fly buzzing around on the ceiling, which was made of square tiles. As he watched he realized that he could describe the position of the fly by the ceiling tile he was on. After this experience he developed the coordinate plane to make it easier to describe the position of objects.

[Cuda84]

René Descartes

 

1596 - 1650

 

 

--------------------------------------------------------------------------------

René Descartes was a French philosopher whose work, La géométrie, includes his application of algebra to geometry from which we now have Cartesian geometry. His work had a great influence on both mathematicians and philosophers.

[Kannon]

just guessin here..

in your post..

code:

---

rot_ccw_pos : 1    #Axis signed direction, 0 = CW positive, 1 = CCW positive  

---

change it to this for positive..

code:

---

rot_ccw_pos : 0    #Axis signed direction, 0 = CW positive, 1 = CCW positive  

---

if I am understanding you correctly

[Jeff Kemper]

Not wondering about posts or machining stuff.

 

Just thinkin positive should be clockwise, kinda like a . . . a clock? Wonderin why it isn't, for CAD/CAM.

[Guest]

i am guessing that because a line has 180 degrees in it,you have to go ccw to get from 0 to 180 degrees.also i think the earth rotates on its axis in a ccw direction.other than that, i don't know.

[MLS]

Just look at it from the opposite end of the axis it rotates upon then it will be.

[Kannon]

if you switch your construction plane to bottom instead of top it rotates cw

[Andy]

Jeff,

 

In math and physics and geometry most graphing work is done in the first quadrant where x and y are positive. If you generate an angle with a line with one end tied to the origin and the other end up and to the right and rotate up in the first quadrant it is a positive angle.

So I suppose they wanted all to be positive in the first quadrant for simplicity, hence +30 degrees. etc.

[gcode]

A wild guess..

the sun rises in the east and sets in the west,

moving in a CCW direction...

 

now... why do clocks go clockwise

[Keith @ Solid Code Solutions]

quote:

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Just thinkin positive should be clockwise, kinda like a . . . a clock? Wonderin why it isn't, for CAD/CAM.

---

Maybe we should change the direction the clock reads?

[Keith @ Solid Code Solutions]

quote:

---

A wild guess..

the sun rises in the east and sets in the west,

moving in a CCW direction...

---

Now that only works if you are basing it relative to north. What if you are facing south??

[Keith @ Solid Code Solutions]

quote:

---

In two dimensions, angular velocity is a scalar quantity. Its magnitude is the angular speed. It is positive for an anticlockwise rotation and negative for a clockwise rotation.

 

In three dimensions, angular velocity is represented by a pseudovector whose magnitude is the angular speed. The line of direction of the angular velocity is given by the axis of rotation, and the right hand rule indicates the positive direction, namely:

 

If you curl the fingers of your right hand to follow the direction of the rotation, then the direction of the angular velocity vector is indicated by your right thumb.

Generally, to describe the angular velocity of a rotation in n-dimensional space requires a vector of components. This number is the dimension (as a real vector space) of the Lie algebra of the special orthogonal Lie group.

---

[rdshear]

If I recall correctly, the clock layout was done to mimic the motion of a sundial in the northern hemisphere. Sundials in the north cast a shadow that moves in a clockwise direction. Thus when clocks were invented, they were made to mimic this motion and the numbers were set to increment in what is now called a clockwise rotation. Maybe if clocks had been invented in the southern hemisphere, they would run the opposite direction.

 

Rick

[Bruce Kanzelmeyer]

Maybe its the old "right-handed" rule. Thumb is x, index finger y, and middle finger z--positive rotation is counterclockwise.

[Keith @ Solid Code Solutions]

quote:

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Maybe its the old "right-handed" rule. Thumb is x, index finger y, and middle finger z--positive rotation is counterclockwise.

---

Dude,

 

That is a way of visuallizing the positive direction of the Cartesian coordinate system the direction of angular lie.

[Guest CNC Apps Guy 1]

In my Tom Hanks voice...

 

"... Plus is positive, minus is negative...!!!!..."

 

[McLaren]

Seriously though, if you drew a clock, and wanted to go from 12:00 to 1:00(positive direction), since you can't move the little hand(your coordinate system)you have to move the clock(your part)counterclockwise.

 

Just like X+ moves the table in a negative direction

[MLS]

Hey James, when you have negative thoughts, does that little propeller thingy on your head start spinning backwards?

 

[Guest CNC Apps Guy 1]

Absolutely.

[Keith @ Solid Code Solutions]

James,

 

Does it spin really really fast when you're concentrating?

[JNO]

Or spin in the opposite direction when you go overseas?

 

 

-

[Thad]

What about when you stick your head in a toilet? Does is move the same direction as the water?

 

Thad teh jumpin' on the bash James bandwagon

[Chip-pan]

Thad,

In that case you would call it a prop!!