Lines and grid coordniation.??? Please help

[OooWeh]

Hello Everyone.I wonder if anyone can help.

 

I am using Autocad 2012 and have found an online tutorial site very informative.

 

The assignment in beginners lesson 1-2, drawing a simple line square, has me baffled

As they mentioned in lesson1-1 that understanding coordinates is very important.

 

Firstly, in 1-2, they ask the reader to select the line tool and then enter the first coordinate of 1,2 as the starting point of the drawing.

Then the following entries 3,2 3,4 1,4 and 1,2 are entered and sure enough a perfect square is created.

 

My first problem is:

As many times I enter a starting point of 1,2 the line always starts in the same place. However, if I start again and enter any other figure the line starts in seemingly unrelated positions.

 

The second problem is:

the coordinates given in this exercise are not equal and should not create a square in my uneducated opinion.

Try as I might I cant find the logical relation between the grid and the coordinates.

 

For example:

The starting entry - 1,2 starts 2 grid lines from the +Y axis and 4 lines from the +x axis.

 

Please could someone help me understand this problem so I can move on.

 

I have scanned all the tutorials and videos I could find including AutoCad for dummies and cant find the answer.

 

Thanks

[rkent]

Look at the attached and see if it explains things for you.

[eldon]

The second problem is:

the coordinates given in this exercise are not equal and should not create a square in my uneducated opinion.

Try as I might I cant find the logical relation between the grid and the coordinates.

 

if you examine the differences in the x and y coordinates for successive points, you will see the logic that will create a square.

[JD Mather]

Watch out for Absolute coordinates # and Relative coordinates.

AutoCAD used to default to Absolute and now defaults to Relative @.

Edited August 3, 2013 by JD Mather

[OooWeh]

Hi Rkent.

Thanks so much for your effort.

The penny has dropped.

What I realized was that the grid actually appears in 1 half increments.

I am no longer confused.

 

Thanks

 

Marc

[OooWeh]

Thanks Eldon.

 

Got it

[OooWeh]

Thanks JD

 

Your advise really helped.

I can now safely progress to section 1.2.

[OooWeh]

This forum is certainly one of the best I have had the pleasure of visiting.