Have you wonder what the Object Class item was in the Map Explorer Tab on the Map Task Pane? Why is there a “Undefined Classes” listed when its expanded? Maybe you heard of this thing called Object Class but wonder why you should use it, after all you use object data and keep all your feature data/information there. So WHY use it? When object classes first came out in Map 6 I took a look at it and said “I don’t need it, I use lisp and vba to create all my new features.” Yes if I need to add a new utility pole on my map I had a command called pole that inserted a pole where I wanted but also created and attached OD to it including default values for the “Date” field and the X-Y location from my coordinate system. If I wanted a new transformer on the map I used my custom command named “TRAN” to do the same thing for the transformer block adding the attributes as it inserted it. Just about all of the mapping I did was with using custom commands putting the proper block on the correct layer scaled to the correct scale and etc. keeping the standards for the maps up to date.
But what if you are not a programmer, do not know lisp or any of the other programming? That’s where the Object Classes come into play.(With some added benefits). Object classes makes it easy to create the features and follow your standards on layer, color, scale and most of any other standard you have and create the data you want to attach to the features. You can also classify existing features with a few clicks. Classified objects are also a lot easier when it comes time to export those features out or when you decide to port everything over to a geospatial data base.
So what’s the added benefit I wrote about above? Have you ever tried to do a search for a value in an object data table? Say you have OD attached to some water meters in you map and one field is for the meter number. How do you locate that one meter with the number of 1234? Well you can attach and query that map then mark the meter with a circle and save back or remember the X-Y coordinate then try zooming to them in the map after you detach it. In other words it was a bit of a PITA to do. With object classes you can use the quick search function in AutoCAD.
Have I convinced you to use them and want to know how? Well there are three toolkits that consist of the files needed on the Autodesk subscription site you can download and try. One for Electric, one for Water and one for Wastewater. Each comes with a readme file telling you how to load them and where to place the files. If you need some help or want to create you own let me know, just leave a comment and I’ll write up some “How-do” on creating them and using them.