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It defines the command MidPoly which does the trick. I mean a small program which goes through all the segments and calculates the distances and then finds the midpoint along the pline. Credits : For Dimention Technologies 

How to replace selected points in a drawing with a defined block in the drawing ? This routine could be more rubust but it is still helpful. It does let you specify the scale of the block and rotation. Command : PT2BLOCK Enter the name of the block that will replace the point objects with ,enter> Specify the insertion Scale Factor Specify the rotation angle Select Point objects that will be replaced by the block. Note: this is not a global point replacement program by default. If you would like to replace all point objects, enter ALL at the command line. Credits :                  Michael Weaver,                           2175 George Road                       Fairbanks, Alaska 99712                     (907)488-3577 voice and fax       ...

Slope is a measure of change in elevation. It is a crucial parameter in several well-known predictive models used for environmental management. One way to express slope is as a percentage. To calculate percent slope, divide the difference between the elevations of two points by the distance between them, then multiply the quotient by 100. The difference in elevation between points is called the rise. The distance between the points is called the run. Thus, percent slope equals (rise / run) x 100. Using this attribute you can easily get the second level as per given slope (%). Instructions ============  Simply enter the first level, required slope in percentage (%) in the attribute and adjust the poly line for the length. Regenerate your drawing 2-3 times it will automatically calculate the second level for you.