Shape.Z field is not visible in model builder

[JulianManning]

I have a simple 2 steps model created in Model Builder:

1. In the first step it takes a 3D point (Shape.Z) and DEM to calculate 'Skyline'.
2. In the second step it uses the 3D point and the output of Skyline to create 'Construct the Line of Sight' 

Since, the inputs in the last step are both Shape.Z aware, then it should be possible to set 'Observer Height Field' and  'Target Height Field' to Shape.Z. However, it only reads Shape.Z of the 3D point and not Shape.Z of the Skyline output.

However, when I follow these steps outside the Model Builder then it works fine and does read Shape.Z of the Skyline. Does anyone knows a workaround or solution to this problem?!

• Sometimes, it shows Shape.Z in 'Target Height Field' but then when I validate the model it vanishes again.
• I've tried activating Z Values in the environment setting, but did not change.

[DavidPike]

Maybe make a copy of the skyline and see if that works in the model.