Here’s a hypothetical situation, you’re a C3D users working with a client and that client wants a copy of your drawing. Well, they don’t own Civil 3D, just AutoCAD LT and, honestly, they don’t even use AutoCAD for anything other then simply viewing drawings. They aren’t going to be changing the drawings or anything along those lines. What do you do? Well, if you’re like most people, you’ll export your Civil 3D drawing to an AutoCAD drawing and send that drawing to the client. Well, I have one word for you, STOP IT!
Before I continue, I’m not going to say that you should never export to AutoCAD, there are some very valid reasons to do so (such as needing to open a C3D 2011 drawing in C3D 2010) but, in the above situation, the recipient of the drawing just needs to see it and perhaps review and comment on it. There is a better alternative – .dwf
So, why use .dwf? First off, when you export to AutoCAD, you lose all intelligence associated with those C3D objects, they become AutoCAD lines, arcs, and circles. If you have a point in C3D, there is an amazing amount of information associated with that point, coordinates, descriptions, user defined properties, etc. Export to AutoCAD and you only get the coordinates (possibly the elevation) and whatever information happened to be in the label at the time of export. Export the same drawing to .dwf, select the point and what do you get? Well, all the information you had in C3D!
The following image shows points in a .dwf file. After selecting one of the manhole points, you can see all the extra data that is available for this point.
If I had exported this drawing to AutoCAD, I would have lost all this valuable information! Another great example of data lost when exporting to AutoCAD is parcels. Export a drawing with parcels to AutoCAD, you get lines. Export a drawing with parcels to .dwf and you get, well, parcels!
Guess what happens if you select an alignment?
You get the idea.
Now, you may be saying to yourself, “But my client needs to use this AutoCAD drawing to help him draw something else!” Well, you don’t want him/her accidentally editing your stuff so, how about you send him/her a .dwf file and they can just xref the .dwf file into their drawing and use it that way?
There are many more advantages to using .dwf files (particularly if you are currently using .pdf files) but that’s for a different post.