many times you will need to change the angular position of an object it could be the position of a house on a piece of property or a chair in a room perhaps a gear needs to be rotated in your drawing there are many reasons that you may need to rotate something AutoCAD is very specific on how it rotates objects as you might have expected you type in the word rotate
to get the rotate command or
let’s open up or drawing
the rotation examples file for Chapter six
and open that up here we already have a few lines drawn at specific angles and some text objects to let us know exactly what those angles are so start the rotate command
select the object that you want to rotate you can pick one or you can pick several you can pick any type of object in AutoCAD press enter now you need to pick a base point of rotation that’s the center point of where you’re going to rotate from if your ortho command is on let’s turn it off press the f8 key to toggle that off
you can see we’re rotating around that base point
think of it as a circle and that’s the center of the circle it’s your center of rotation here everything will pivot around that point
the second point you select determines the angle amount you’re rotating so where I pick
is where we’ll end up or you can type in an angle amount so let’s rotate this 120 degrees
and there you go we can also rotate in the opposite direction select your objects pick your base point
then type in a negative number negative 120 in this case press ENTER and that puts our lines right back to where we started from a positive angle of rotation we’ll rotate your selected objects in a counterclockwise direction same way when AutoCAD draws an arc it draws it in a counterclockwise direction so it starts here on the right moves up and to the left then down to the right the negative direction or the negative angle goes in a clockwise way 360 degrees now the angle of rotation is based off of the horizon you may have noticed that or due east to the right of your screen your angle starts there horizontally and it comes out from your base point and then goes up from there so when I grab this line drawn it zero it looks like
rotating it from the line itself well I am in this case but if I grab one at 45 degrees
the base point
as you can see
the line that I’m rotating has a 45 degree angle from where I’m at so if I need this line to go 45 degrees I just type in 45 degrees it’s relative but if I need it to go to the 60 degree line I have to do some math I can go 60 degrees which is where I want to go where I’m at leaving me at 15 degrees so I have to tell it rotate positively 15 degrees and there it is there are two lines here now
if I wanted to go to a specific angle I can do something different I can type in my rotation command select my line enter my base point
to go to that 60 I can just type in rotate 15 degrees but sometimes you have no idea what that angle is you don’t know what the angle is you need to be at and you don’t know what the angle is that you’re currently at so for example let’s cancel that out and let’s just draw a line at any angle we have no idea what this line is and what the angle of it is so let’s start the rotate command select the line press Enter now pick your Base Point which is right here use your Oh snaps
now type in our for reference press Enter
we want to pick a reference angle or a reference line so typically you’re going to want to pick the exact same base of rotation point again and then you want to pick a point on your line which is going to be the end point in this case and now instead of starting at the horizontal position I’m starting here and I can put it exactly now where I want it to
all right there
you can see this line is drawn right over the top of it so I had no idea where I was at but I put it exactly where I wanted it to go and that’s a great feature so let’s look at these angles here and we’ll do the example again type an
pick your 15 enter base point if I want this to go to 30 and I type in 15 degrees
it goes there if I rotate again select my object enter pick my base point and now go to reference you can pick it right on the command line or just type in the letter R REE pick your base point of rotation pick the end point and now type in the number 30 it right to the 30 degree line it didn’t rotate 30 degrees but it went to the 30 degree line so that’s fantastic if I have a line
drawn at some weird angle that I don’t know I could take the time and measure that angle again or if I want it to just be horizontal and go to the zero angle start the command rotate pick my base point pick my objects hit R for reference my same base point of rotation the same point here and now I type in zero
and I’m horizontal that’s a cool trick so you have two basic ways to rotate your objects one is by a relative angle and then one is to an absolute angle there’ll be different cases and different reasons to use either one it just depends on their situation now there was another option
you may have noticed it
for pick our base point again of copy
work again but it will also leave the original where it is I type in 90 there it goes so it copied and rotated that line so that’s a something that can be very useful to you as well
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