Understanding scale concept and units in Autocad…

I wanted to write this article, which will help you to understand the AutoCAD’s working logic and learn some concepts like scale and unit, if you have just started using AutoCAD or if you are learning it by yourself.

First of all, I would like make clear that, whichever drawing you are making, area that you are substantiating this drawing is called modelspace. If you are using AutoCAD 2000 or higher versions, you have noticed phrases like “Model / Layout1 /Layout2” over the small tabs under the area which you are making the drawing. Do not forget that you make your drawing in Modelspace.

Just on the lower left corner of Modelspace, there is an icon that shows x and y axes. This is called UCS (User Coordinate System) icon. This icon shows the coordination system according to which you are currently making your drawing. Arrows pointing at x and y directions shows the + direction of Modelspace.

Now we can mention the subject of scale and unit. Coordinate system in AutoCAD Modelspace is cartesian coordinate system. If you take 0,0 point as origin where x and y values are 0 (this is the lower left corner of your screen), values towards right and up will be positive. Accepting 0,0 point as origin, x-axis is 0 degree towards rigth according to degree angle system. Angles will be according to counter clockwise, y-axis will be 90 degrees in + direction, x-axis will be 180 degrees in – direction, and y-axis will be 270 degrees in – direction.

We know that the drawing you make in AutoCAD is called model and the area in which this drawing is made is called Modelspace. This point is very important, drawing isn’t done by scale like it is done on paper, it is done as 1=1 and scaling is made when printing on paper. However, it is important how you accept 1 AutoCAD drawing unit. AutoCAD paper (layout) unit is mm(milimeters). Let’s say, you are drawing a architectural project and you accept 1 drawing unit as 1cm. So, you started your drawing with the assumption of 1 dwgUnit = 1cm. You continue drawing according to certain rules like the doors will be 100 units, height of tables will be 75 units. Thus, you draw everything on the cm basis. When you take print out, if you don’t change the scale, each 1cm will look 1mm as the AutoCAD unit is milimeters(mm). In other words, it will be printed as 1 dwgunit (we accepted as cm) = 1mm, which means 1/10 scale. In order to take print out, you should state in the scale part that your 10 drawing unit (that is to say 100 mm) shall look 1mm on paper, which is 10=1.

I hope it does not look complicated. In order for your AutoCAD drawings to be precise and to take print outs according to any scale at any time you desire you should make an acceptance for 1 drawing unit and you should draw according to one on one scale.

I will be glad to answer if you have questions. I wish you nice works.

Glove compartment fo AutoCAD: Dashboard 1

Glove compartments are very handy in our cars even if we have noticed it or not. Especially if you are sharing your car with your wife, imagine what kind of things you may have in it. Indeed, the most important advantage of glove compartment is that you can access small items that you use very frequently at a distance of grasp of your hand. In a similar manner to this, DASHBOARD feature that came together with AutoCAD 2007 is providing such a functionality. Even though DASHBOARD is more or less some kind of a TOOLPALETTE, it has some particular differences. Controls on it are slightly different. Besides, you cannot add tabs to DASHBOARD. You cannot customize DASHBOARD in AutoCAD 2007, but since AutoCAD 2008 it is customizable now. However, usage of DASHBOARD is mainly based on control panels rather than tabs. Now, let’s start learning by taking a look at how DASHBOARD looks first (Fig. 1).
Fig.1

In Fig. 1, you can see the DASHBOARD that belongs to AutoCAD 2008. Please note that each control panel is divided by a line. Each panel consists of controls like mini buttons, combo lists, sliding bars etc. That is the main difference compared to TOOLPALETTEs. Moreover, each panel can expand in between each other (Fig. 2).
Fig.2

Expanding and contracting operations are done by using the double arrow icon in down direction ( expanding ) or double arrow icon in up direction (contracting ) that can be found just beside the large icon that represent each panel. Its usage is pretty simple. DASHBOARD, similar to TOOLPALETTE, can be either docked or can be opened/closed automatically. We can make these settings from the mini menu that is just under the gray ( or blue ) band.
Fig.3

If you also would like to have wide drawing area like me, then you can choose the ‘auto-hide’ option. It is also possible to open or close different control panels again from the same menu. Before finishing the article, let me remind you once more how to open or close DASHBOARD. If the dashboard is closed then you can open DASHBOARD by entering DASHBOARD from command line or select Dashboard from the Window menu.

Glove compartment fo AutoCAD: Dashboard 2

As we mentioned in our first article, DASHBOARD can be customized in AutoCAD 2008. In order to do this, we can right click on anywhere on DASHBOARD and select ‘Custimize Commands…’. Indeed, what we are doing is to open the AutoCAD customization window or CUI file editor (Fig. 1).
Fig.1

Different than the previous AutoCAD versions, there is an additional ‘Dashboard Panels’ title. At this stage, we have two things to do; (1) we can select any one of the existing panels and edit it, which we don’t recommend, (2) or we can add a new panel and edit it, which we suggest. I created a new panel named as ‘Sample Panel’. As we mentioned in our previous article, panels are composed of controls. These controls are made up of a hierarchical structure as panel, panel row and controls. You can also add ‘flyout’ objects which are small icon menus which come up at the end of mouse cursor when you hold left clicking. In our example, we are going to create a new panel that has one single row and layer control menu. As you can see in Fig. 2, one row is automatically created in the new panel that we added.
Fig.2

At this stage, our empty panel looks like as shown in Fig. 3.
Fig.3

What we are going to do is simple drag-and-drop the commands that we will use onto the panel. You can find the layer management command among the AutoCAD commands (Fig. 4).
Fig.4
While creating the example, we used AutoDESK Architectural. For this reason, menu group then is shown on the screen is ADT. We must add layer list control after that. Controls can be found under ‘Control elements’ title (Fig. 5).
Fig.5

When we add both of the controls to our new panel, then we will get a row as shown in Fig. 6.
Fig.6

Now, we have a new control panel. Our new panel is already placed inside the DASHBOARD (Fig. 7).
Fig.7

Indeed, layer control was already existing in DASHBOARD. You can make more creative arrangements. However, I would like to remind you once more about one thing that you must pay attention to. Do not make your arrangements over the existing panels. By this way, if you regret any changes, all you have to do is to delete the new panel that you have created.