Understanding the user coordinate system (UCS)

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The user coordinate system or UC S as we refer to it

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establishes the location and orientation of

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a movable Cartesian coordinate system.

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The UC S is an essential tool for

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many precision operations because it defines things like

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the horizontal and vertical directions used for features such as Ortho

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mode, polar tracking

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and object snap, tracking,

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the alignment and angle of the grid hatch patterns, text and dimension objects

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as well as the orientation and origin

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for coordinate entry and absolute reference angles.

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Now let's talk about the U CS icon by default,

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it appears in the lower left corner of the drawing area.

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And for the current model viewport, you can see it here as a default setting.

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If we go to paper space,

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the paper space, UCS icon is a triangle.

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As you can see here in this layout. Tab

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various visibility settings for the UCS are available by typing in the UCS

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icon command.

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Once we press enter, you can see the different options,

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you can have the icon

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on or off. So for example, if you didn't want to see the icon,

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you can choose off and the icon disappears,

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but we can go back in and turn it back on

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very easily.

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Some of the other options we have

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all will take your settings and turn those settings on all of your Viewport U CS icons

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in paper space and model space.

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We have origin

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and no origin.

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Let's go ahead and talk about origin first.

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You'll see that it doesn't look like anything happened with the U CS icon.

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However, if I were to draw a line

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and have it go to zero comma zero

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and then do a zoom extents.

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You'll notice when I zoom out a bit, the U CS icon is actually at zero comma zero.

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And if I continue to zoom out or zoom in, it stays at zero comma zero.

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So if I go back into us

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icon and this time, choose no origin,

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I can go ahead and

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erase this line. I don't need it anymore, but already look at where the ucs icon is.

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It's not at an origin. So now if I do zoom extents,

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it has no bearing on the zoom factor or where

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I am in the drawing because I chose no origin.