adding breaklines to tin producing strange results (grading a tree pit)

[daniel.phillips3R4ZM]

Hello all, I'm attempting to add breaklines to a tin surface, with the process being creating feature lines from polylines and having the points inherit the elevation of my EG surface (with intermediate break points). 

However, when I modify the elevation of the smaller feature line and attempt to add both to the surface, I notice that I get some strange results, with tringles sticking into the space where there should be a smooth tree pit defined.

  I know I'm missing something here, please help!  I've attached some screenshots and the file itself for convenience.  

[Neilw_05]

The proper/best practice workflow for creating new data is:

1) Develop the new surfaces as separate surface models.

2) Create a new model and paste the original surface first, then the new surfaces. The result will be the original surface with the new surfaces merged in.

DO NOT add breaklines to the original surface! This is a bad practice! Keep the original surface as-is and paste it into a new surface as the backround.

[daniel.phillips3R4ZM]

Hi there thanks for the response the file should be attached to the original post. I was working wotb the assumption that I could grade an existing surface using feature lines as break lines. Similar to creating a grading group/surface 

[Neilw_05]

 As I said, do not mess with the original surface. Paste it into a new surface and paste the new surfaces after. The pasting process will override the original surface. This is key to the process. Do this first and then post if you need help.

[daniel.phillips3R4ZM]

Thanks Neil, I'm a bit confused, are you saying there is a way to paste a surface "into" another one?  Or is this simply a clipboard (control c, control v) process?  When I paste one surface onto another one, they both remain as separate entities (IE defined with different names from the prospector).

It seems strange to me that I couldn't just add the new contours to the existing surface as a breakline-isn't that the whole point of breakline features?

[Neilw_05 · Accepted solution]

Here is your file with modifications to help you see how it works.

I took the EG surface and pasted it into FGMERGED. Pasting is done by right clicking on the Edit group in the surface properties in the Prospector tree. I created a surface for each of your circular polylines and pasted them into FG Merged. You will see the result is a perfectly formed surface where they are added.

Simply adding breaklines in the EG surface will fail because the breaklines only influence the triangles next to them. Thus the EG surface will remain intact between the breaklines. What you want is for the new triangles to form between the breaklines and then the new triangles need to overwrite the EG triangles that they cover. This is where the pasting process comes into play. It wipes out the triangles and replaces them with the new ones. Please review the tutorials on how to work with surface models. This is essential to working with the software.

[daniel.phillips3R4ZM]

Hi Neil,

Yes, this is great thanks for your extra assistance here! One final question, should I keep the the proposed basins/etc around to use as a "comparison" surface in the volumes dashboard to compute cut/fill? Thanks again, you rock.  

[Neilw_05]

You will need to keep everything intact. If you remove the polylines, their surfaces will dissolve and you won't get volumes. Your volume surface will be FGMERGED minus EG.