change elevation of surface

[Anonymous]

I know how to change the elevation of an entire surface, ie reduce z with 0,5 meters for all points, but I want to change the elevation a little in some areas and a bit more in some others. How do I do that?

Typically I have a surface for the ground level. I want to lower (copy) this surface to represent a soil layer. I have a number of soil sample points in which I have x,y,z for the bottom of the current soil layer. Between the samplepoints I want the soil layer to "follow" the ground level. Example: I have one point with 0,5 meters of sand and the next point (50 meters away) with 1 meters of sand. The two points are on the same ground level but between the two points the ground level varies a lot (±2 meters). A straight interpolation between the two points would have the bottom of the sand layer going over the ground surface.

You might say I want to "drape" the ground level on the sample points.

I hope you understand what I want to do?

[tcorey]

I'm am not totally clear of your objective, but I can say that this sounds like a job for Feature Lines. These can be draped on a surface, adjusted as needed and then added to a surface as breaklines.

Tim

[neilyj666 · Accepted solution]

Create a surface from your sampled xyz points- ensure that the depth is positive. You may need to add dummy points to extend outside the current surface

Createa volume surface with the sample points surface as base and current surface as comparison

Create a new surface and paste the volume surface in.

[neilyj666]

This creates a dynamic differential TIN that more sample points can be added as required and the base of soil will dynamically update. It also follows the existing surface based on the sampled depths. It isnt perfect but it works pretty well in the majority of cases

[Anonymous]

That worked excellent. Thank you!

[neilyj666]

HTH...:)