The emphasis in AutoCAD 2008 is on 2D, especially on annotation. This fits with Autodesk's parallel emphasis on making AutoCAD appear to be a 2D product. The user interface is not much different, other than the addition of new buttons and droplists.
Some changes were made to make AutoCAD more compatible with ADT (now renamed AutoCAD Architectural 2008) and Inventor. ADT 2008 junks VIZ Render in favor of AutoCAD's mental ray rendering engine. In turn, AutoCAD lights now support wattage information and IED data. Materials have new properties, reflect light better, and also support the IED standard.
To make AutoCAD more compatible with Inventor, a new dimension type is introduced: Inspection. This type of dimension has the value, a tag, and a percentage.
A new option equally spaces dimension lines. The other addition is the jogged linear dimension.
You can now specify colors, linetypes, lineweights, and plot styles individually for each viewport. Because the Layer dialog box is now so big, you can specify which properties to display.
There is a new Layer Settings dialog box that determines whether other users are notified when new layers are added to xrefs and the current drawing. A balloon appears in the tray.
Layer states have been underused and hard to access, so they've been brought into the foreground with their own dialog box, as well as a new droplist in the Dashboard.
AutoCAD 2007 moved all of the layer-related Express Tools into the core command set. One of them, LayIso, has been enhanced. In the past, it turned off all layers, except the one belonging to the selected object (hence, isolating it). New in 2008 is the ability to fade the other layers, rather than just turn them off. The faded layers are locked: you can see them and osnap to them, but cannot edit them. Very nice touch!
Bill Fane rejoice! The new SetByLayer command forces blocks and other objects to take on the color specified by the layer. This works for nested blocks, as well.
A second dashboard now exists for 2D drafting. The Dashboard can be customized with commands and droplists, although it does not appear that you can add custom macros to it.
The single biggest new feature is annotation text, which I'll call AText from now on. This text is different because of two new properties: Its size (scale) and display (on or off) is dependent on the scale factor of the viewport in which it appears.
For example, when you specify a scale factor of 0.125 in the style of the AText, then that text appears only in viewports which also have a scale of 0.125. That's the simplest aspect by which to understand it.
Model space has a new drop list on the status bar, which lets you specify the scale factor of all text in model space. Select a different scale factor from the drop list, and all text changes correctly (by that I mean, size and justification).
Paper space has two such drop lists: one to specify the scale factor of the current viewport, the other to specify the scale factor of text in the viewport. (No more Zoom XP!) Normally, the two droplists are linked: change vp scale to 1:50 and the text also changes its scale to 1:50. But you can unlink them if you need.
If text in a viewport does not match the scale factor, then it is not displayed. No worries: an option overrides the invisibility cloak, allowing you to see all text in the viewport, including that which does not match the viewport scale factor. AText can have multiple scale factors attached, through the new ObjectScale command. That lets it appear in multiple viewports of differing scales.
AText works with every type of text, except RText, I was told. A new icon appears near the crosshair cursor when it passes over AText. (The icon looks like the cross-section of a triangular architect's ruler.)
MText can now split a long column of text into multiple columns. It can also specify spacing between paragraphs. It imports from Word 2003 and 2007 with formatting intact.
The new spell checker checks spelling in dimensions, zooms into misspelled words, and ignores words with nubmers.
AutoCAD already has Leader and QLeader, so why not add MLeader -- leaders with multiple leader lines. MLeader also keeps text (or block) attached to the leader, can justify all selected leaders, and combine multiple leaders into one. New leader lines can be added to existing MLeaders, and there are new editing grips on the mleader line. MLeader Styles let you predetermine what the mleader will look like.
Autodesk keeps trying with the InfoCenter, its attempt at make help always available. Now the InfoCenter has been moved onto the toolbar: type in a word or phrase, and a droplist shows related help items. The Communication Center is moved from the tray to the new InfoCenter, and a Favorites button has been added. The CommCenter allows RSS feeds.
(I told you this is the annotation release of AutoCAD!) The new DataExchange command links tables with Excel 2003/2007 spreadsheets. The link is two-way, so changes in the table and the spreadsheet are reflected in each other. The link is through the XLS file, not through OLE. But you might not want the table updated in AutoCAD, so that can be prevented; by default, cells in the AutoCAD table are locked to prevent accidental change, but you can unlock them.
Here is a scenerio:
1. Make change in Excel.
2. Save the change.
3. In AutoCAD, a notification balloon appears in the tray, alerting you of the change.
4. You can accept or reject the change.
The new DataLink command allows you to modify links. The Excel table is included with packages created by the eTransmit command.
The split-long-mtext-into-multiple-columns feature also applies to tables: long tables can be split into columns.
Now properties of objects can be extracted, such as the length of a polyline -- attribute extraction is no longer limited to blocks. If you create custom rows or columns, these are no longer overwritten the next time you extract data.
When a DWF file is imported as an underlay, you can now specify which layers to display. Still no importing (translating) of DWF files into AutoCAD.
DGN Import & Export
MicroStation DGN files can be imported -- translated into objects (for editing) or displayed as an underlay (for visual accuracy). This is limited to 2D drawings only. AutoCAD drawings can be exported to DGN format.
You can now directly edit layout tabs. For example, click the name twice to change it; hold down the Ctrl key, and then drag to copy the tab. Both the tab name and layout contents are copied.
The little brother gets everyting found in AutoCAD 2008, except for the data exchange items and the 3D changes.
...that's all, folks.