Is it possibe to isolate an element type based on an irregular surface levels ?

[administratorJSJUA]

Hi, a little bit of a background, we are doing a project with 800 drainage pits, and we need to calculate the bulk earthworks, we have an irregular existing surface, not at a constant slope, and we have hundreds of pits above the existing surface, which would require filling and hundreds bellow the existing, which would require cutting

We have a 3d model of the pits and drainage, so i can do a volume surface against the existing and get global figures, that's fine,  but...

Is it possible to know how many pits are above the existing surface ??? if i create a block to represent the pits, is it possible to quick select, or isolate the ones that are above the irregular surface ??? i know you can do it with a fix elevation, but do you know if we can do it for a whole irregular surface ??? 

thanks 

[cwr-pae]

Off the top of my head: If you have a TIN surface for the finished elevations, create a volume surface (comparison surface) Create cogo points for each pit, set their elevations to the volume surface. Create a point group of all points above elevation 0 and a second point group of all points below 0. By using the point group to select the points you can get a count of selected objects in the properties palette. If select the point group tree ehading you get a disply of points in each group in the item view window.

[rl_jackson]

I had a site a while back that had hundreds of small spoil biles sitting the site. I had the EG (drone flight) that I'd produced the TIN from. With that I went around the site drawing a feature line at the approximate bottom of each bile that I would push to the EG surface for elevation. Once that was done I created individual surfaces (using the counting feature for surface name from the featurelines, in my case this was my approximate site grade once done I would create a volume surface for each bile. It was difficult, but got the job done. 

[samir_rezk]

Hi @administratorJSJUA 

I don’t have a perfect solution but there is an idea that can get you closer!

On your Volume Surface:

1. go to surface properties / analysis tab
2. Select an elevation Analysis
3. choose a range of 2 and select the arrow to send it down!
4. configure your ranges from min elevation to 0 for the first one and give it a nice color and from 0 to max elevation for the second range, choose a different color.
5. Then apply a surface style that has the elevation display light bulb turned on
   
   

This can visually tell you (based on color) which pits are in fill vs cut; you will need to count them though!

hope this helps a little,

[lynn_zhang]

Hello @administratorJSJUA ,

Just checking to see if your problem has been solved. Have you tried the suggestions above and did any of them work? If yes, please click on the "Accept as Solution" button in the reply so this helps other users in the community find the solution too. Thanks!

[Neilw_05]

Great idea. You could also generate the cogo points automatically using MAP and the centroids of the pits (assuming they are not extremely irregular in shape). Look up centroids in the Map Help System.