This question comes up a lot so I recorded a video to show you how to use TBC functions to elevate points or nodes on a line using slope extracted from a line segment

First question - I have a line that has two elevated nodes that define the slope between the nodes, and I want to extend the slope of the line to a point projected e.g. 5’ beyond the end of the line segment to elevate the point - how do I do that.

Use the Change Elevation Command and the Relative to Point mode. Select the end of the line nearest the point as the reference point and select the same node again to define the reference elevation and then for the vertical angle (read slope) you are going to use the SHIFT key held down and then click on the line segment from which you want to derive the slope and click the segment beyond the halfway point at the end at which you want to derive the slope from - i.e. if a line slopes upwards from Left to right at 5 degrees then if I click on the right hand side of the line (about 75% along the segment) it will determine the slope is 85 degrees and if I pick at 25% along the segment it will determine the slope is 95 degrees. Be sure not to snap the end of the line segment, always snap in the segment itself and away from the end point using the SHIFT and Click approach. Click Apply to add the elevation. Turn on the point elevations in View Filter Manager to see the results.

Second Question - I have one line that has 2 nodes that have elevations and therefore a slope between them - eg the front and back of a parking bay curb. On another segment elsewhere in the job, I have a similar line segment but on that one they only give me one elevation in the plans. So I want to add a second node elevation to the second line using the slope derived from the other segment that has a slope - how do I do that?

Use the Linestring Editor in Vertical Mode. Instead of using Elevation Mode, select the Inbound or Outbound Slope (depends on which end of the segment has an elevation and which direction the line is drawn in, and then select the node that is not elevated for the distance along and then for the outgoing or incoming slope value - click the other line segment that has the desired slope again using the SHIFT plus Click approach outlined in the first question above.

Video below shows you how