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standards:sitework_surfaces_and_layer_definitions

Sitework Surfaces and Layer Definitions

AGTEK's Data organization starts at Surfaces and those surfaces contain layers which either form the surface or are related in some way to that surface.

Primary Surfaces

The basic set of surfaces are Existing and Design. It is possible to have one without the other but no volumes or cut/fill color can be calculated without at least these two surfaces.

Existing

The existing surface is a representation of the ground before any dirt is moved. The Data Lines layer within it contains lines and points that form the actual surface model used for 3D display and differenced with other surfaces for volumes and cut/fill color.

Design

The design surface is a representation of the finished result after dirt is moved. Elevations on it may be to the top of the dirt or to the top of finished surface (ex: asphalt in parking lot, a finished floor concrete pad, or top of gravel). In situation with materials other than dirt are accounted for, the user usually creates Sectional Areas that form a subgrade surface for volumes and machine control modeling. The primary reason a user might use this method is that if the engineers change sections, it's is very easy to modify a sectional area depth and recalculate volumes. The Data Lines layer within the Design surface contains lines and points that form the actual surface model.

Secondary Surfaces as Modifiers

(optional but predefined) A long but descriptive name. These surfaces are separate but modified copies of the Existing and Design surfaces created by entering closed polygons that depress the Existing and Design surfaces within their limits.

Subgrade

The subgrade surface represents the finished site surface at the top of dirt. Subgrade is created by combining the Sectional Area layer of the Design surface with Design Data Lines. A sectional area is defined as a closed polygon with a depth of x. Design data lines within its boundaries are depressed by that depth to form the subgrade surface. The most common usage is to offset elevations on plan elevations given in “finished” grades like a concrete pad or asphalt street. If a Sectional Area layer exists, then the Subgrade surface is created.

Stripped

Stripped is the Existing ground surface equivalent to a Subgrade surface. Before moving dirt on a site, the contractor typically removes an upper layer of vegetation/topsoil. In situations where topsoil is scarce like the NE, they stockpile the topsoil and then respread it over the non-hardscaped portion of the site. Even when topsoil is not scarce, a site is stripped to remove vegetative matter that will deteriorate otherwise and cause unstable soil conditions. Like Sectional Areas, Stripping Areas are defined as a closed polygon with a depth. Existing data lines within its boundaries are depressed by the amount of specified depth and form a Stripped surface. If a Stripping Area layer exists, the Stripped surface is created.

Other Surfaces

These surfaces are optional and do not modify any of the other surfaces although in some cases they can be based on other surfaces. Other names surfaces are:

Strata

Strata surfaces (up to 9) model material layers (rock, mud, water, etc.) beneath the existing ground. Data entry is limited to creating borings (Strata boreholes in Existing Surface) relative to the existing ground layer. From that data, the program creates contour lines to represent the Strata surface. The names of Strata layers are entered by the users (Rock, mud, etc.) and have an order that cannot change in the boring entry.

Current, Previous, and User named Surfaces

These surfaces can be used as scratchpads, intermediate versions, or contain specialized information like overexcavation and pipe trenches. They contain a more limited subset of layer types

Layers in surfaces

Surfaces
Layers Existing Design Stripped Subgrade Strata User
Data Lines X X X X
Annotation X X X
Perimeters X X
Stripping Areas X (1)
Benchmarks X X X X
Strata Bore Holes X X
Strata Break Lines X X
Profile Lines X X X X
Contours X X X X
Cut-Fill Labels X X X X
Cut-Fill Lines X X X X
Haul Path X X
Pipe Lines X X X X
Report Regions X
Sectional Areas X (2)
Balance Regions X
Stake Point Lists X
Driving Simulation X
Highway Data X
Stage Areas X
Survey Data X

* User named surfaces include Current, Previous, Overex, Sewer, Storm, Water

(1) Stripped does not have layers within it but is the result of modifying the Existing surface with Stripping areas.

(2) Subgrade does not have layers within it but is the result of modifying the Design surface with Sectional areas.

Layer Definitions

  • Data lines - the lines and points that form the respective surfaces. The most important data in any file
  • Annotation - Annotation is lines and point that do not modify their respective surface. At the most basic level they simple serve as a 2D guide. The most common usage is as something to be assigned an elevation and then be converted to a data line.
  • Perimeters - Perimeters control the surface and volume calculations.
    • Existing Perimeters are closed 2D polygons that limit ALL surface generation outside of its limits. In the case of an existing perimeter within another, the innermost perimeter is a hole in ALL surfaces. Two existing perimeters that are not overlapping are considered an Island situation. Both perimeters calculate surfaces within them.
    • Design Perimeters denote limits of excavation and are closed 2D polygons. They limit surface generation for Design and Subgrade surfaces to the area within their limits. At their most common, the process of creating a Design perimeter prompts the user on whether to create a matching 3D drape line in the Data lines layer. This drape line has its elevations derived from the Existing Surface and effectively makes the Design surface match the Existing surface at the perimeter boundary. This is commonly called “daylight”. A Design Perimeter within a Design Perimeter creates a hole in the Design Surface (the existing surface is visible through this hole) and is also usually daylighted. Two Design perimeters that do not overlap create an Island situation. In this case, two separate design meshes are created within the perimeters with no surface existing outside of the perimeters.
  • Stripping Areas - Stripping Areas are closed polygons with no elevation but a uniform depth and name assigned. The Existing ground data lines are depressed within the bounds of a Stripping area and the result is the Stripped surface. Stripping areas are exclusive in their depth and are not additive. A stripping area within another stripping area with a depth of 0 results in a hole in the larger stripping area.
  • Benchmarks -
  • Strata Bore Holes
  • Strata Break Lines
  • Profile Lines
  • Contours - The contours layer is primarily for contours generated by AGTEK software. They have no effect upon surface generation and serve mostly as an easily understood 2d representation of a 3D surface. They can be copied and pasted into a data lines layer if the user wishes to use them for surface generation.
  • Cut-Fill Labels - User generated points that display on the cut-fill map and printouts.
  • Cut-Fill Lines - reference lines created when
  • Haul Paths
  • Pipelines -
  • Report Regions - Report Regions are enclosed 2D polygons used to segment site volumes for reporting.
  • Sectional Areas
  • Balance Regions
  • Stake Point Lists - Individual, user entered points for use in surveying.
  • Driving Simulation - A user drawn 2D line that serves as a playback path in the 3D view driving simulator.
  • Highway Data - lines created by the Highway module such as COGO.
  • Stage Areas -
  • Survey Data

Application Specific Notes

SmartDirt

SmartDirt really only cares about data lines and the perimeters that clip them. A minor exception would be the benchmarks used to calculate alignment. The remaining layers do not have any calculations applied to them and are either displayed for reference or not at all.

At this time, SmartDirt does not save any data. In the future, there may be a need to save isopach's and/or tracks with time stamps. Tracks with times stamps could probably be stored in Survey Data and displayed. Setting the elevation of such tracks to 0 would automatically cause them to be properly treated in the desktop software.

Layer Usage

M = Mesh D = Display C = Clip

Layers Usage
Data Lines M,D
Annotation D
Perimeters (1) C,D
Stripping Areas D
Benchmarks (2) D
Strata Bore Holes
Strata Break Lines
Profile Lines
Contours
Cut-Fill Labels
Cut-Fill Lines D
Haul Path D
Pipe Lines D
Report Regions D
Sectional Areas D
Balance Regions D
Stake Point Lists
Driving Simulation
Highway Data D
Stage Areas D
Survey Data

* User named surfaces include Current, Previous, Overex, Sewer, Storm, Water

(1) Existing Perimeters clip ALL surfaces for meshing, Design Perimeters clip Design, Subgrade, Strata, etc but does not clip Existing or Stripping surfaces. (2) Benchmarks are used to calculate alignment.

standards/sitework_surfaces_and_layer_definitions.txt · Last modified: 2012/10/10 16:01 (external edit)