AutoCAD Land Desktop

AutoCAD Land Desktop

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rajanikanth_wgl
Posts: 1
Registered: ‎10-28-2004
Message 1 of 6 (1,556 Views)

cut and fill earth volume calculation

1556 Views, 5 Replies
10-28-2004 03:53 PM
Hey guys,
I'm new to land development tool. I have been trying to calculate cut and fill volume of a contour area. Before jumping on to the project i practised most of the tutorial examples provided by the software tool.

i spent most of the time on tutorial 12 and 17 and learned how to prepare terrain modular and stratum e.t.c.

I understood the concept of creating surfaces, but FG.

My question is:

How to prepare future ground surface?

Here is what i did to prepare future ground.

I created a text file using notepad with the information of
number, northing, easting and elevation.
then i imported the points in to plan and also created the fg surface
using point file.

i followed the step by step of tutorial 12 and 17 to create the eg and fg surfaces.

when i execute the program using of the three methods, i'm getting an message of site not overlapped and sometimes an error message.

Please help me understand the concept of this future ground surface.

Thanks a lot

Raj
*Don Reichle
Message 2 of 6 (1,556 Views)

Re: cut and fill earth volume calculation

10-28-2004 04:08 PM in reply to: rajanikanth_wgl
Hey Raj; Preparing the FG surface is dependant in the type of developement. Think of the difference between residential subdivisions, and commercial shopping malls with parking lots. Just as there are different types of development, there are different types of designers. You will probably get answers from quite a spectrum on this forum. For residential subdivisions I invariably use Alignments and Cross Sections to model the grading. That way I can assign Point Codes to the Finish Grade surfaces, as well as the Excavation surfaces. I use these Point Codes to generate 3D breaklines that model both types of surfaces, Finish Grade (for aesthetics) and Excavation (for quantities). For commercial developments I will use a combination of Alignments where possible for the travel lanes, and then finish off the rest of the parking areas with 3D breaklines that follow the site plan for islands and front row parking. These are all set to Finish Grade elevations, and I then use Terrain>3D Polylines>Create Curb to offset to the Excavation surface. I use the 3D breaklines almost exclusively because they allow the best modeling capabilities for most instances. -- Don Reichle Hacker Engineering, Inc. "King of Work-Arounds" LDT & CD 2004 C3D/LDT 2004 On HP Pavilion a367c 2.80 Ghz/512MB RAM XP PRO - SP2 "rajanikanth_wgl" wrote in message news:6390577.1099004021392.JavaMail.jive@jiveforum1.autodesk.com... > Hey guys, > I'm new to land development tool. I have been trying to calculate cut and > fill volume of a contour area. Before jumping on to the project i > practised most of the tutorial examples provided by the software tool. > > i spent most of the time on tutorial 12 and 17 and learned how to prepare > terrain modular and stratum e.t.c. > > I understood the concept of creating surfaces, but FG. > > My question is: > > How to prepare future ground surface? > > Here is what i did to prepare future ground. > > I created a text file using notepad with the information of > number, northing, easting and elevation. > then i imported the points in to plan and also created the fg surface > using point file. > > i followed the step by step of tutorial 12 and 17 to create the eg and fg > surfaces. > > when i execute the program using of the three methods, i'm getting an > message of site not overlapped and sometimes an error message. > > Please help me understand the concept of this future ground surface. > > Thanks a lot > > Raj
*Mike Norton
Message 3 of 6 (1,556 Views)

Re: cut and fill earth volume calculation

10-29-2004 06:43 AM in reply to: rajanikanth_wgl
Raj, In order to compare surfaces the FG surface must be contained entirely within the boundary of the EG surface.The error message you mention indicates this may not be the case. -- Mike Norton Total CAD Sytems Inc Houston, Texas "rajanikanth_wgl" wrote in message news:6390577.1099004021392.JavaMail.jive@jiveforum1.autodesk.com... > Hey guys, > I'm new to land development tool. I have been trying to calculate cut and fill volume of a contour area. Before jumping on to the project i practised most of the tutorial examples provided by the software tool. > > i spent most of the time on tutorial 12 and 17 and learned how to prepare terrain modular and stratum e.t.c. > > I understood the concept of creating surfaces, but FG. > > My question is: > > How to prepare future ground surface? > > Here is what i did to prepare future ground. > > I created a text file using notepad with the information of > number, northing, easting and elevation. > then i imported the points in to plan and also created the fg surface > using point file. > > i followed the step by step of tutorial 12 and 17 to create the eg and fg surfaces. > > when i execute the program using of the three methods, i'm getting an message of site not overlapped and sometimes an error message. > > Please help me understand the concept of this future ground surface. > > Thanks a lot > > Raj
*Steve Cannon
Message 4 of 6 (1,556 Views)

Re: cut and fill earth volume calculation

10-29-2004 08:08 AM in reply to: rajanikanth_wgl
Hi Mike, I agree with you that the 'not overlapped' message indicates that, in plan view, the EG and FG surfaces share no common ground. When this message occurs, Raj needs look at the xy locations of the two surfaces to see if the two surface boundaries share a common area. The easiest check is to import the 2d-border for each surface and perform a visual inspection. In Raj's case, I suspect it is most likely it is a coordinate base problem. I will disagree with you contention that: "In order to compare surfaces the FG surface must be contained entirely within the boundary of the EG surface". LDT will compute a composite surface and volume for any strata in which the two surfaces share ANY common area. The controlling surface does NOT need to be contained ENTIRELY within the limits of the EG surface, any subset will do. In Autocad terms, for any given strata, if one imports the 2d-boundaries for each surface, converts both to regions, and can perform a solids intersection of the two regions without a null region being created, LDT will compute a composite volume between the surfaces contained within the intersecting region. In applied practice, if one is aware of this, there some instances where it could save some time. You are correct that in MOST applied land cases, the user will want to compute a volume over the limits of the entire controlling surface, and therefore it is DESIRABLE to have the FG surface contained entirely within the boundary of the EG surface. The fact that the LDT composite earthwork routine reports neither a composite area nor an 'unsolved area' within its statistics often leads to user prepared reports that include unintended cut or fill omissions. Such a reported statistic would be a useful flag that one needs to re-examine the limits of the two surfaces. I have occasionally caught unintended omissions by importing the 2d-polyline boundary of the composite surface, and compared its area to the 2d surface area reported by the controlling surface's extended statistics. Users should never trust the reported cut and fill volume without doing a series of checks on the authenticity of those volumes. sc "Mike Norton" wrote in message news:418248f1$1_1@newsprd01... > Raj, > > In order to compare surfaces the FG surface must be contained entirely > within the boundary of the EG surface.The error message you mention > indicates this may not be the case. >
*Mike Norton
Message 5 of 6 (1,556 Views)

Re: cut and fill earth volume calculation

10-29-2004 08:28 AM in reply to: rajanikanth_wgl
Good point, Steve. I'll remember that the next time I want an incomplete volume. -- Mike Norton Total CAD Sytems Inc Houston, Texas "Steve Cannon" wrote in message news:41825cca$1_1@newsprd01... > Hi Mike, > > I agree with you that the 'not overlapped' message indicates that, in plan > view, the EG and FG surfaces share no common ground. When this message > occurs, Raj needs look at the xy locations of the two surfaces to see if the > two surface boundaries share a common area. The easiest check is to import > the 2d-border for each surface and perform a visual inspection. In Raj's > case, I suspect it is most likely it is a coordinate base problem. > > I will disagree with you contention that: "In order to compare surfaces the > FG surface must be contained entirely within the boundary of the EG > surface". LDT will compute a composite surface and volume for any strata in > which the two surfaces share ANY common area. The controlling surface does > NOT need to be contained ENTIRELY within the limits of the EG surface, any > subset will do. In Autocad terms, for any given strata, if one imports the > 2d-boundaries for each surface, converts both to regions, and can perform a > solids intersection of the two regions without a null region being created, > LDT will compute a composite volume between the surfaces contained within > the intersecting region. > > In applied practice, if one is aware of this, there some instances where it > could save some time. You are correct that in MOST applied land cases, the > user will want to compute a volume over the limits of the entire controlling > surface, and therefore it is DESIRABLE to have the FG surface contained > entirely within the boundary of the EG surface. The fact that the LDT > composite earthwork routine reports neither a composite area nor an > 'unsolved area' within its statistics often leads to user prepared reports > that include unintended cut or fill omissions. Such a reported statistic > would be a useful flag that one needs to re-examine the limits of the two > surfaces. I have occasionally caught unintended omissions by importing the > 2d-polyline boundary of the composite surface, and compared its area to the > 2d surface area reported by the controlling surface's extended statistics. > > Users should never trust the reported cut and fill volume without doing a > series of checks on the authenticity of those volumes. > > sc > > > > "Mike Norton" wrote in message > news:418248f1$1_1@newsprd01... > > Raj, > > > > In order to compare surfaces the FG surface must be contained entirely > > within the boundary of the EG surface.The error message you mention > > indicates this may not be the case. > > > >
*Laurie Comerford
Message 6 of 6 (1,556 Views)

Re: cut and fill earth volume calculation

10-29-2004 12:44 PM in reply to: rajanikanth_wgl
Hi, Extending on Steve's analysis, when computing earthworks volumes the user has to define a "Site". If the user Imports both 2D boundary borders first they then have the data they NEED to make the best estimate of the site location and in particular rotation. To get the most reliable computation for grid and cross-section volumes, one axis of the site should be parallel to the longest axis of the area of intersection. It is very easy to select this angle graphically using the intersection area of the polylines as a visual guide. When prompted for the angle select a point to the left of the intersection area and then a second point inside the quadrant between 45 degrees below the X axis and 45 degrees above the X axis from the first point. -- Laurie Comerford CADApps www.cadapps.com.au "Steve Cannon" wrote in message news:41825cca$1_1@newsprd01... > Hi Mike, > > I agree with you that the 'not overlapped' message indicates that, in plan > view, the EG and FG surfaces share no common ground. When this message > occurs, Raj needs look at the xy locations of the two surfaces to see if the > two surface boundaries share a common area. The easiest check is to import > the 2d-border for each surface and perform a visual inspection. In Raj's > case, I suspect it is most likely it is a coordinate base problem. > > I will disagree with you contention that: "In order to compare surfaces the > FG surface must be contained entirely within the boundary of the EG > surface". LDT will compute a composite surface and volume for any strata in > which the two surfaces share ANY common area. The controlling surface does > NOT need to be contained ENTIRELY within the limits of the EG surface, any > subset will do. In Autocad terms, for any given strata, if one imports the > 2d-boundaries for each surface, converts both to regions, and can perform a > solids intersection of the two regions without a null region being created, > LDT will compute a composite volume between the surfaces contained within > the intersecting region. > > In applied practice, if one is aware of this, there some instances where it > could save some time. You are correct that in MOST applied land cases, the > user will want to compute a volume over the limits of the entire controlling > surface, and therefore it is DESIRABLE to have the FG surface contained > entirely within the boundary of the EG surface. The fact that the LDT > composite earthwork routine reports neither a composite area nor an > 'unsolved area' within its statistics often leads to user prepared reports > that include unintended cut or fill omissions. Such a reported statistic > would be a useful flag that one needs to re-examine the limits of the two > surfaces. I have occasionally caught unintended omissions by importing the > 2d-polyline boundary of the composite surface, and compared its area to the > 2d surface area reported by the controlling surface's extended statistics. > > Users should never trust the reported cut and fill volume without doing a > series of checks on the authenticity of those volumes. > > sc > > > > "Mike Norton" wrote in message > news:418248f1$1_1@newsprd01... > > Raj, > > > > In order to compare surfaces the FG surface must be contained entirely > > within the boundary of the EG surface.The error message you mention > > indicates this may not be the case. > > > >
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