Using Text Tool to annotate spot elevations :: bug?

When I use the Text Tool to annotate spot elevations, this is what I do:

  • The vertex or control point I am spotting must not be grouped.
  • I choose the Text Tool then hover over the vertex until it highlights (very brief).
  • Click and drag.
    = The red, green, blue (x,y,z) elevation shows up as leader text. Very handy.

However (see attached file) it does not always work properly:

  • When the Text Tool is applied to the endpoint of Line A, IT reports (–21’, 0’, 0’) as it should [with the exception of the double negative prefix to 21; anyone know what this is about?].

  • An error occurs when the Text Tool is applied to the endpoints of Line B. It reports z positions of “-0”. These points are actually 0.451’ below z=0.

  • Similarly, a problem arises when I take spot elevs from the “STACK”.

The “leaves” of the STACK are spaced 1’ apart.
The STACK is displaced upward by 0.540’

  • The spot elevations taken about z=0 are correct.
  • The spot elevations below z=0 are incorrect, showing integer elevations with a double negative prefix.

I might be missing something, but this doesn’t seem correct. Is anyone else seeing this?elev error?.skp (54.9 KB)

oops correction:
“The spot elevations taken about z=0 are correct.”
should read:
“The spot elevations taken above z=0 are correct.”


The numeric text in TextTool objects reflect, the Precision setting in ModelInfo > Units.

So some rounding may be happening.

Hi Dan,
Many thanks for responding.
I thought about rounding issues, as well—but the errors are so large, they are way outside the rounding parameters of SU, especially considering they are spot on when above z=0. And then there are the double negative prefixes… I just wonder if some flag came adrift.

Here’s another example, probably a lot clearer.

Elev Error 2.skp (51.7 KB)

Indeed, something is wonky. I changed the units to six places and get the same results just with more places when I add new texts. The first endpoint below z=0 should be [40.024, 0, -1] but shows z=-0 instead! The rest are also off by one and get the doubled negative signs. This seems like a formatting error in the text object.

Thanks for having a look.

My workaround has been to make an xy plane at a z elevation meaningful to
the DTM (to put ‘zero elevation’ where I want it), then drop verticals down
to it from salients in the terrain. The Text Tool can then be used to label
the verticals (but not the endpoints) to annotate their lengths.

Part of the terrain in an Add Location operation always falls below z=0
anyway, so the workaround has advantages. But there is something screwy
going on, for sure.