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Creating a digital model

D6RXW_GPS

Member
Joined
Sep 23, 2007
Messages
11
Location
Wisconsin
Occupation
Operating Engineer, soon to be retired.
I've operated a Trimble equipped dozer for 5 yrs but have never got into creating the digital model for plugging into the system. All I've ever done is put the card in the display. Can anyone give an explanation of how the paper plan is digitized to a card and what the cost of doing it is.
 

SE-Ia Cowman

Well-Known Member
Joined
Oct 22, 2009
Messages
240
Location
Iowa
I have seen it done once, the engineer pulled the layers that I needed out of autocad then sent them to my cat dealer, via email, were they converted them with Trimble Buisness Center to a dxf file then emailed them back to me were I downloaded it in to my Tsc 2 then put the card in the TSC 2 and exported the plan to the card for the dozer. As far as the cost goes I dont pay the bills so I cant tell you.
 

Bigironjim

Well-Known Member
Joined
Oct 8, 2010
Messages
51
Location
TEXAS
Occupation
Lard, wishes, manure, nails, bongo's, flyswatters,
D6RXW: The digitizing a complex design from paper plans involves special equipment, a digitizer, that has a mat or board as well as a mouse-like tracer with a magnifying glass. Depending on the program being used it created a cad file, perhaps a .dxf, that will be imported to business center, or SVO, for conversion to the linework and surface files needed in the Trimble system.
 

MarkChambers

New Member
Joined
Jan 4, 2012
Messages
2
Location
Murray KY
Occupation
Project Manager
Digital models can be either a headache or as simple as a quick file conversion depending on the designer and what format they put it out on. If the engineer has supplied a DWG format or DXF format file from Autocad, it makes it fairly straightforward. You simply import your topo lines and make sure they are all on the correct elevation. This can be easy or hard too though lol. You'll usually have a lot of cleanup to do as you do this...sometimes the lines come segmented and you actually have to go through and pick each segment to make sure they're a closed loop in a continuous line (typically called a polyline) it's tedious work..you also need to have a set of the original paper plans handy because theres no telling how many times ive come across variations from paper plans to digitized plans. If you're digitizing from paper plans it just more tedious work. As BigironJim said above, its a tracing project with some specialized equipment but the good thing there is that after you've done the tracing, you know your line elevations are going to be correct. After you've got all your topo lines and grades set, building pad subgrades, roadway subgrades etc put in then you'll need to convert the 3d line drawing into a digital terrain model. Trimble and Topcon both have their own software to do this and most of the 3rd party takeoff software will have a way to do this as well. You'll have to have a good general knowledge of CAD drafting techniques and some basic design engineering concepts to be able to pull off a successful 3d model. I'm not sure how much this costs either unfortunately...we've always done it in house as both my brothers and I have been able to put our heads together and usually get a good working model. I would assume it's not cheap simply because of the amount of time it takes to get one right. Good Luck.
 

MCguy

Member
Joined
Nov 9, 2011
Messages
16
Location
Cleveland, Ohio
I've beed build models for 10+ years now and Chambers is spot on in his reply, except for one small thing: I would never digitize any plan to be used for machine control or layout. Its just not accurate enough in my opinion. I do alot of site jobs, but recently changed jobs to a highway construction company. The site jobs depending on you tolerances, quality control and expectations you could digitize you plan for a model, I dont suggest it though. All project now days should have the Cad files accessable to the contractors, if they dont ask for them. If its a private project and the engineer is reluctant to issue the files, go to the owner and explain to them the importance of accuracy and how your company uses the accuate machine control systems to build their product. As a owner that hires a private engineering firm to design a project, the owner owns the files, and they think they dont call a lawyer.

As for highway work, it becomes a bit more complicated but much more simpler at the same time. Centerline/Baseline offset is the basic format in build a road project. you have typical sections throughout a road that can be applied to a baseline. Personally I will build a road project in steps starting with the easiest sections first, such as tangent sections were the road is mostly a typical crown. Next I will move to the radial section were the cross section is usually a superelevated surface. and lastly the transitions from tangent crown sections to superelevated sections I will usually build by hand and eye; looking for smooth transitions from crown to superelevated. Finally, most of the projects I work on now are highways so there are on and off ramps. I will build those last from the point were they are not directly tied to the mainline and basically tie those into the mainline by using the locations typical section and transitioning it to the ramp itself.

Its not as difficult as it seems, its really knowing the software your using and basic surveying/layout knowledge in understanding slopes, profiles and cross sections.

As for costs; I've been freelancing most of the years Ive been in the industry, and typical model pricing is this:

for basic site projects were the custom only wants a finish grade file with the linework, no subgrades, no roadways; just taking contour information and converting it to 3D and if there are curbs, sidewalks, building pads,ect it will run $400-500 and acre.

If there needs to be subgrades added to the file I will usually add $100 an acre (typically anyone can build from a finish grade model if the subgrades mirror the finish grades)

On highway/road it breaks down like this: a shoulder to shoulder only model will run $500 per mile/per one vertical profile (so in a case of a 4 lane highway $500x2=$1000 per mile)

For highways/road that have medians, curbs, side slopes i charge $1500 per mile ( all the median slope, curbs, and side slopes all need to be calc'ed by hand and then imputed to 3D format)

So thats a bit of breakdown of 3rd party cost, and in house cost are going to vary depending on how you or your employee's salary is setup. I can tell you though that I just built a 8 mile highway, the Eastbound only shoulder to shoulder and it took me 55+ hours just for the 3D model. I add a bunch of other line work files and such for out field guys like MOT plans, barrier wall locations, stripping lines, etc so that they dont bother with calling our surveyors to come layout something so simple. I typical add a lot of line work files and go though each phase (some highways have 3-4 phases) so that they understand were things are like barrier wall, stripping phase edge lines, etc.
 
Joined
Feb 17, 2009
Messages
15
Location
COLLEGE STATION, TX
Occupation
CONSTRUCTION SURVEYOR
Unless you are doing something as simple as a pad or retention pond, and end even then not, never us a digitizer for a model. You need the accuracy of a cad file to get quality grading. For DOT jobs you can use station offset from a baseline to build everything, but again need the correct cad software. I use carlson and once you learn it, which takes time and repetition, it is pretty easy. Then again, Tiger makes golf look easy. Remember, garbage in garbage out. For machine control to work correctly you need a good model and site calibration.
 
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