By Dennis Collin
The Pale Blue Dot picture is an iconic photograph of Earth taken on February 14th, 1990, by NASA’s Voyager 1 spacecraft.
Voyager 1 was speeding out of the solar system out beyond the planet Neptune, about 3.7 billion miles from the Sun, when mission control commanded it to look back toward home for a final time. It captured a series of images that were used to create the first “family portrait” of our solar system.
One picture that would become known as the Pale Blue Dot shows planet Earth within a scattered ray of sunlight. Voyager 1 was so far away that from its vantage point Earth appeared as just a point of light, about a pixel in size. Outer Space is a big place and so is the AutoCAD drawing environment.
When new users start to learn AutoCAD, it is also easy to get lost in this big environment. On a drawing board the drawing limits are obvious, the edge of the sheet of paper / film. In AutoCAD however there are no real true limits as AutoCAD’s model space are infinite just like Outer Space (maybe!).
Fortunately, AutoCAD has many ways of navigating this environment and can bring into focus any elements that are temporarily lost. The Zoom command is one of the first AutoCAD commands users learn and is the primary way of exploring the virtual drawing space. As with many commands the Zoom function is full of options with different ways of navigation. However, one option that is often missed by many is the Zoom to selected Object(s) function.
Should an element get drawn and not appear on screen where expected, use the Zoom Extents command. Most likely the screen will show a large area of model space, a bit like the big expanse picture taken by Voyager 1 (see initial image & Fig 1.). This will happen usually to a user who accidently added too many zeroes on coordinates or dimension values. Should this occur try the following process:
At the command prompt, type ‘Select’, when prompted to Select Object, type in the word ‘Last’.
This will select the object that was last created by the user and will be selected even if it is not currently visible on the screen. If looking at a large area a few blue pixels may appear somewhere on screen.
Now type in Zoom, and after pressing enter, choose the option ‘Object’ and the screen should focus on the errant element. The element can either be moved to the main drawing area or deleted so that when the Zoom Extents option is chosen, the expected drawing should fill the screen as Fig 4. below.
AutoCAD is a complex piece of software; drawing elements correctly, navigating AutoCAD’s environment, layers, annotation and plotting etc. are just some of the topics covered on Cadline’s AutoCAD Essentials Training Course. After three days instruction with an Autodesk Certified Instructor, users will have a good grasp of AutoCAD and be able to produce and deliver drawings with a good level of proficiency. The training will include example hands-on tutorials and 3 months post training support on relevant course topics. For more information on Cadline Training and other services visit https://training.cadline.co.uk and visit our live chat facility or call us on 01784 419922.