Smoothing Surfaces

[ryan.yepp50361367]

Does smoothing the surface change the volume in which is calculated from?

[cadtag]

not 100% sure, but if the TIN lines used after smoothing are different than the TIN lines used prior to smoothing, then the answer is almost certainly yes.

[rkmcswain]

Yes. It does.

[Iceberg]

Yes. When you smooth a surface you are adding additional points to the surface. These points are called derived points.

[ryan.yepp50361367]

Let's say I have 2 surfaces (A and B). Certain portions of A is the same elevation as B. If I were to do volume tin with A compared with B, the cut/fill volume of the area in which A and B has the same elevation should be 0. If I were to smooth both A and B surfaces, would the area with the same elevation still have cut/fill volume of 0?

[Iceberg]

Let's say I have 2 surfaces (A and B). Certain portions of A is the same elevation as B. If I were to do volume tin with A compared with B, the cut/fill volume of the area in which A and B has the same elevation should be 0. If I were to smooth both A and B surfaces, would the area with the same elevation still have cut/fill volume of 0?

If you have a calculated point at that same spot then yes, it would be the same. If after smoothing the surfaces you have a derived point in the same spot, or near the same spot it might be different. Since you are working with 2 different surfaces that have been created using different information (I am assuming here), when the TINN is created it is using different elevations to triangulate, and you might get a slightly different elevation at that spot.

I would use the inquiry tool and list the elevation in a few spots to see what the elevations are between the two surfaces and from there you should be able to determine the surface elevations.

[i-reyes750480]

If you need to preserve the area that is at the same elevation, just extract that area from both surfaces, hide the area with a boundary smooth the surfaces and paste in back the extracted parts. If you are not sure witch area is at the same elevation, use minimum distance between surfaces to check it.