MODEL SPACE

Okay, so now let’s get into the SPACE…! Yes, I am not kidding, the Model Space in AutoCAD is the Real, Three Dimensional, Infinite Space...! Isn’t it great? You can Model the entire Eiffel Tower, The Great Grand Canyon or even the Himalaya at its actual size. Why, you can model the Globe of Planet Earth itself if you wish, provided that you have millions GHZ processor, billions TB of memory and trillions TB hard disk space…! Now I am kidding! No, you will not really need all those but modeling the Earth will definitely require enormous state-of-the-art computer systems. Anyway, let’s get back on to the track…

So what we have here in the Work or Drawing Area is a Three-dimensional infinite space, just like what we have around our planet. However I am claiming so much about this space, what we can see is a flat black rectangle with one arrow-like symbol and one crosshair-like cursor and both look very tiny. Alright, let us befriend these little primary elements so that we can have a smooth, pleasurable and productive journey.

When we open AutoCAD, what is displayed is the TOP VIEW or PLAN, as it is popularly called. Being an orthographic projection it obviously is shown in two dimensions X and Y respectively. Although we are working in the space, as long as we are dealing with only TWO dimensions, we are restricted a 2D PLANE. The default Plane is XY plane and it is formed by TWO axes perpendicular to each other.

Note – You need to set the crosshair value to 100 to see the above effect. You can do it from Tools – Options – Display – Crosshair

Orientation Circle – This is an imaginary concept followed by AutoCAD which has three basic elements –

Origin (0,0,0)
A horizontal line running along the length of the plane is our X axis and the vertical line running along the length of the plane is our Y axis. The point where these axes meet / intersect is our ORIGIN whose x, y and z values are 0, 0, and 0. You can consider this as our start point and you better stick to it for a proper and better organization of your drawing.

Angle or Direction

1. The Right direction of X axis is considered to be 0 degree or 360 degree (East Direction)
2. The Up direction of Y axis is considered to be 90 degree (North Direction)
3. The Left direction of X axis is considered to be 180 degree (West Direction)
4. The Down direction of Y axis is considered to be 270 degree (South Direction)

Quadrants
The two axes X and Y divide the Orientation Circle into 4 Quadrants

1. First quadrant – The part above the X axis and to the Right of Y axis. This is the quadrant where we are supposed to work as this is the only quadrant with both X and Y values positive for any given point.
2. Second quadrant – The part above the X axis but to the Left of the Y axis. Here although the Y values of all the points would still be positive, the X values of all the points would be negative. ‘Not recommended’ for use.
3. Third quadrant – The part below the X axis and to the Left of the Y axis. Here both the X and Y values of all the points would be negative. Strictly ‘Not recommended’ for use.
4. Fourth quadrant – The part below the X axis but to the Right of the Y axis. Here although the X values of all the points would still be positive, the Y values of all the points would be negative. Again ‘Not recommended’ for use.

Tomorrow we will learn some skills needed to maneuver our newfound infinite space.

Stay Tuned…!