Results 1 to 3 of 3

Thread: Composite volume versus grid surface volume calculations

  1. #1
    Member
    Join Date
    2008-12
    Posts
    11
    Login to Give a bone
    0

    Default Composite volume versus grid surface volume calculations

    I am working on a drawing that a contractor producer. They created a volume calculation on a 11 Sq. mile site. They calculated a composite and grid cut and fill added them together and got the average. My question is that I have always used a composite volume calculation. Is there any documentation that describes the best method to use?

  2. #2
    AUGI Addict
    Join Date
    2015-12
    Location
    Arizona
    Posts
    2,419
    Login to Give a bone
    0

    Default Re: Composite volume versus grid surface volume calculations

    In theory the Composite method is more accurate that the grid method.

    However they may both vary widely from each other due to the level of detail used to create either, the Existing Ground model, or the Finished model, and the grid spacing.
    Changing the grid spacing alone can greatly impact the reported volumes. I used to run preliminary numbers with a fair large grid space (LDT) to save time in processing. Then for final numbers I would run the volume(s) with increasingly smaller grid values until the percent change from the previous was very small.
    Although I would still do what the contractor did. I would run a Grid Volume, AND a Composite volume; not only to check one against the other, to sum them up and average them out.
    As with any analysis, the more data points you have to compare the higher the accuracy of the results derived from your sample set. (In Theory)

  3. #3
    AUGI Addict sinc's Avatar
    Join Date
    2004-02
    Location
    Colorado
    Posts
    1,986
    Login to Give a bone
    0

    Default Re: Composite volume versus grid surface volume calculations

    I view grid volumes as obsolete for most purposes, and pretty much never use them anymore.

    If you keep setting your grid spacing to smaller and smaller values, you should get results that converge pretty close on the composite volume. Both methods are limited by the accuracy of your Surface. But if you have a bad Surface, you won't get better volumes by using grid instead of composite, unless you just happen to get lucky (e.g., you have a spike in one of your Surfaces, and your grid points happen to miss the spike). I don't like relying on luck, so I don't view comparing Grid and Composite volumes as a good check.

Similar Threads

  1. 2015: Répercussion d'un paramètre partagé de matériaux d'un volume vers ses sols de volume
    By eric.lehy-meira695599 in forum Revit Architecture - Général
    Replies: 2
    Last Post: 2015-04-22, 10:25 AM
  2. Volume calculations in structural foundation schedule
    By jkh in forum Revit Architecture - General
    Replies: 1
    Last Post: 2010-07-27, 02:44 PM
  3. Soil volume calculations
    By Jonnydubya in forum AutoCAD General
    Replies: 2
    Last Post: 2008-08-18, 02:29 AM
  4. Volume calculations
    By Old Jim in forum Civil 3D - Civil Design Companion - General
    Replies: 3
    Last Post: 2005-11-09, 08:18 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •