3 best ways to draw an oval

1. Rectangular and Fillet

Draw a rectangular and fillet all four corners with a radius that is half the length of the small sides of the rectangular.
For example, if you want to make an oval 120×50 then follow the next commands / inputs:
 rec ¦ click a point for the lower left corner ¦ @120,50 ¦ f ¦ r ¦ 25 ¦ p ¦ click on any point on the perimeter of the rectangular
Your oval is ready!

2. Rectangular only

This is the fastest way! You just draw a rectangular and use its fillet parameter with the desired radius. The only disadvantage with this method is that the radius value you specified is now the default value for the next rectangular you will draw. So, in order to make a normal rectangular, you must change the radius parameter back to zero.
Again, if you want to make an oval 120×50 then follow the next commands / inputs:
 rec ¦ f ¦ 25 ¦ click a point for the lower left corner ¦ @120,50 
Your oval is ready!

3. Circles + Rectangular and Trim

The next method is not recommended because it's much more complex than the previous two, but it's always interesting and useful to know an alternative way to draw things in autocad.
Again, we have to draw the same oval as before 120×50. Draw a circle with radius 25 (half the length of the small side). Copy the circle by 70 to the right (or to the left, it doesn't matter). Number 70 derives from the length 120 minus 2×radius. So, we have 120 - (2×25) = 70. Next, draw a rectangular and snap the first corner to the bottom quadrant of the first circle and the second corner to the top quadrant of the second circle (the quadrant snap point must be enabled). Finally, trim every line there is inside your oval and your shape is ready.
p.s. If you need a closed shape (which is recommended), you have to Join the lines of your oval beacause with this method they are not connected. The sequence of the commands / inputs will be:
 c ¦ click for the center of the circle ¦ 25 ¦ cp ¦ click on the circle ¦ move the mouse to the right (with ORTHO) and enter 70 ¦ rec ¦ click the two corners as described above ¦ tr ¦ enter to choose <select all> option ¦ select all four lines inside the oval
Your oval is ready (but keep in mind that the shape isn't closed).

20 commands you never knew their existence!

1. BATTMAN

BATTMAN is the Block Attribute Manager. Use it to manage attributes in a specific block. With it you can edit values and other properties of all attributes that are already in a block in a file.

2. DBLIST

This command will list every entity in the drawing. Useful when you think you have some entities that are not showing up. You can erase everything visible and then run DBLIST to see what else is still there.

3. DIMROTATED

Imagine trying to dimension something that doesn’t have parallel or perpendicular pick points. So when you pick the 2 points for the dimension, it will normally create the dimension so that it is perpendicular to those 2 points. With the command DIMROTATED you can now specify the angle that you want the dimension to be perpendicular to.

4. EATTEXT

This command doesn’t really exist in AutoCAD anymore but you can still type it in. EATTEXT used to be the Attribute Extraction wizard but was replaced with the Data Extraction wizard. But EATTEXT is much more fun to say than DATAEXTRACTION.

5. EDGEMODE

Using the system variable EDGEMODE can simplify your Trim and extend functionality. Did you know that you can TRIM and EXTEND to non-existent edges?

"0" Uses the selected edge without an extensions. 

"1" Extend or Trims the selected object to an imaginary extension of the cutting or boundary edge.

6. FACETRES

This command adjusts the smoothness of shaded objects and objects with hidden lines removed. Valid values are from "0.01" to "10.0".

7. GRIDSTYLE

If you use the Grid command, you will find the new look makes the polar tracking hard to see. If you change value for GRIDSTYLE to "1", it will take the grid back to the pre-2011 dotted appearance. If you set it to "2", it will display the dotted grid for the Block Editor. If you set it to "4", it will display the dotted grid for Sheet and Layout.

8. GRIPMULTIFUNCTIONAL

AutoCAD 2012 has a great new feature called multifunctional grips and works on a little bit of everything in AutoCAD. If you hover over a grip you will see these new pop-up menus. It is important to remember all of these are also accessible by picking the grip and right-clicking also. For some people, these new pop-up menus have become annoying and cause them to wonder if there is a way to turn them off. GRIPMULTIFUNCTIONAL has multiple variables that you can use to fine tune how you want them to work for you. Using "0" will turn off multi-functional grips altogether. Using "1" will allow you to access the grip-goodies by holding down the control key as you click. Using "2" gives you hover-only grip menus. Finally, selecting "3", which is the default setting, gives grip menus with or without using the CTRL key.

9. MBUTTONPAN

Type this command to set whether or not the middle mouse button causes the screen to pan around. Type "0" after you enter the command, and you’ll have a situation that will very much annoy your colleague that left his or her computer unlocked.

10. OOPS

This command will undelete the last object that you deleted. This is nice if you accidently delete something but don’t realize it until you have already done a lot of work. Normally you would UNDO the delete but you don’t want to UNDO your work! OOPS and it’s back.

11. OVERKILL

OVERKILL is what you enter on the command line to start the Delete Duplicates command. It will clean up your file be removing duplicate lines and other objects.

12. PEDITACCEPT

Setting this variable to "1" will kill the prompt about converting lines, arcs, and splines into polylines. By setting this to "1", the objects will automatically convert to a polyline and save you a step.

13. SAVEIMG

If you just need a quick screen capture of your AutoCAD display, this command can do it. Plotting will result in better output with more options, but if you just need a quick file, SAVEIMG can do it.

14. TASKBAR

The TASKBAR system variable will allow you to have multiple drawings open as separate items on the Windows taskbar.

15. TEXTTOFRONT

The drawing order of objects is very important in CAD drafting. Many times, people forget to bring text and dimension forward before plotting, especially if they are behind a solid hatch. The TEXTTOFRONT command brings all your text and dimensions to the top of the draw order stack without having to select them all first.

16. TSPACEINVADERS

This is an undocumented command. Essentially, you perform a selection and it will show you TEXT and MTEXT that has entities blocking it. It doesn't do the cleanup, but in a crowded drawing it can help you identify text under linework, etc.

17. WHIPTHREAD

AutoCAD can utilize multiple processors by setting the WHIPTHREAD variable. By default this is set to "1", which only REGEN is sent to the secondary processor. Setting this to "3" will maximize AutoCAD’s performance when panning and zooming along with REGEN and REDRAW to the secondary processor. Don’t expect your computer to magically turn into a rocket ship, but every little bit helps.

18. WHOHAS

This command will tell you "who has" a file open. Read only is fine unless you want to actually do some work in the file. Run the WHOHAS command, browse to the file you want to check and pick it. AutoCAD will tell you who is holding on to your file.

19. ZOOMFACTOR

Type this in and it will give you a dialog box asking what the zoomfactor is. It should be "60" by default. You can set it from "3" to "100".

20. ZOOMWHEEL

This sets how the wheel interacts with you. For example, rolling forward is zooming in and rolling backward is zooming out. If you use other software this might be different. If you want to swap how this feature works then changing the default value from "0" to "1" will reverse the behavior.