Freeware from Cadhedral downloads
TerrainSectionsPro2X 2.2
With this FREE AutoCAD add-on you can create terrain sections from geodetic points(heights) in the drawing. You can also specify position of pipe(cable, road, ...) or set auxiliary marks in the section. Text settings, scale in X,Y axis, height of the reference plane and type of the terrain section can be set at start-up. There are two ways how you can create terrain sections: 1) Terrain section from known X,Y coordinates Enter values for X,Y coordinates, specify marks position and terrain section is drawn in real time as you type values. 2) Terrain section from the drawing with geodetic heights Specify points on-screen and type `Y` if you want to enter Y-coordinate(terrain height). You can also specify marks position or use `Interpolate` option to calculate terrain height from two near terrain heights. Terrain section will then be created in a new drawing.
Internal CADviewer 4.2
INTERNAL CADVIEWER is FREE DWG viewer that can be launched directly from your AutoCAD. With this AutoCAD add-on you can browse, view or open drawings stored on your computer or CD-ROM(e.g. DWG catalouges). You can view or open next, previous, first or last drawing in the current folder(folder of the current drawing). You can also view a sequence of drawings in slide show with defined time delay. Thumbnail mode gives you the ability to view multiple drawings simultaneously in reduced size. Drawings can be open directly from their thumbnails. There is also thumbnails slide show available. Open button enables you to select another folder with DWG files or you can open another drawing. Selected folder can be added to the favorite folders.