3D Data: More than Machine Control

3D Data: More than Machine Control

For many years, our business has been centered on the production of 3D data for machine control. This is the low hanging fruit of a civil site. High dollar paving, building pads, and retentions are easier to do and higher quality with machine control. Fast forward to current times.

Many civil sites are being completed with machine control. The use of the equipment on the job site has become a reality, to the point that contractors have started to look beyond their current use of the possibilities in their hands. As many of you know, I have long been a proponent of leveraging data for a job site. I have worked with many of our clients to better use the data they have in their hands and drastically improve production and profits.

I will talk about several ideas that are good next steps for users of 3D site data. These are in no particular order of profitability, any site may or may not be able to use any of these processes. Not to worry, I will back up the explanations here with a video to better explain these ideas.

2D and 3D Points

Once the domain of survey, a point has specific and relative information. I’ll use points for laying out a curb arc as an example; 3D points for the PC and PT of a curb arc give us the location and elevations of that curb run. We know the slope between the points and paving elevation is an easy calculation. Next we add the arc center as a 2D point, now there is a pivot to actually swing an arc for form or string line layout. Increasing the power of points, we offset the curb line to allow the field to set string line for a curb machine.

Site Layout

Using earthmoving equipment to get the dirt right is a huge time saver. We also advocate the use of positioning technology for more than grading;

Electrical; It started with light pole bases and quickly escalated from there. We now regularly provide data as 2D or 3D points for;

  • SES pads. The job has been checked so we are good with drainage and elevations on the site. The electrical service slab is easy to calculate from available regulations.
  • Common area in-ground power. Many plaza shopping centers have electrical connections for decorations and kiosks. Knowing the 3D location of these allows for electricians to easily set these right the first time.
  • Common area hardscape. Everything from playground equipment to benches, these additions need some type of base and connection. Know where things go and they can be done while access is easy and save re-digging to set later.

Utilities

We have been providing utility layout for years. We show points 10 feet apart on the flow-line for pipe with horizontal offsets if needed. Structures are marked as well. The advent of successful machine control for excavators has allowed us to provide a trench network so the operator can dig trenches correctly the first time.

Other utility details can benefit from information provided in the data;

  • FES’s, wing walls and valley gutters. These concrete structures are better done in rough grade but many contractors wait until near the end of construction and field fit. With a correctly prepared model there is enough confidence to build these when it’s convenient to the crew.
  • Water lines are usually specified as a minimum depth below finish grade. We build the line in the data so crews can place it at any time and not require wheel trenching making a mess of the just completed grading.
  • Subdivisions have utility connections for each lot, we handle this one of two ways;
    • We can layout all the laterals and they are placed according to plan. When it’s time to make the connection, the rover is used to find the location of the pipe.
    • When the utilities are not well defined or connections have to move, as-built shots are taken and we update the model for easy use in the future.

 

As-Builts

Taking shots along the way provide an ongoing record of what is being done. This helps to establish production rates as well as the basis for submittal drawings in the future. Here is one way to bring this into your workflow;

  • I call this the “daily topo walk around”. While reviewing the work being done on a site, the superintendent has a rover and takes ground topo shots as well as items being put in the ground. In a perfect world, points would be coded but that is not critical.
  • We often are asked to convert these walk around topo’s into as-builts or progress takeoffs. With the model on the screen overlaid to the topo points, we usually can figure out what the shots represent.
  • Utilities are the biggest winner with as-built points. Before covering, if the top of pipe is measured, those are later converted to as-built drawings we put together for closing submittals. Many contractors have an issue with this, and we get it. It’s one thing to get the points but now the office needs to do full blown CAD drafting and plotting.

I will help to tie these ideas together in a video linked HERE. Please don’t hesitate to ask any questions you may have regarding these or other issues.

Chasing Perfection on Civil Sites

Chasing Perfection on Civil Sites

We need to strike a balance between a picture perfect model on the screen and a well-priced practical job that performs well. Nobody wants us or their model builder to make some infinitely detailed model that would be so dense it would slow down machines. Not to worry, I’ll include a video to show you what I’m talking about.

Now to the details.

Parking lots

With the thousands of jobs we work on in any given year, parking lots are by far the most difficult. The reason is that the parameters are very specific but most plans lack sufficient information to accomplish this.

Plans should include:

  • All areas needing to drain correctly.
  • Slopes in common areas which need to support safe walking.
  • Handicapped parking spots requirements for slopes.
  • Grade breaks that will divert water to designed drainage structures.

In the past, the surveyor would blue-top spots from the plans and a grader operator would fulfill the above requirements. Now that we can do it digitally, it is important to check and verify plan intent so the blade operator can go full automatic in the field and get a good surface. When the data is not built correctly, an operator must field fix to make sure the rules are followed.

We are not going to go as far as running rainfall calculations to check engineering. We must however respect flow direction and grade breaks to deliver a smooth surface.

Here’s how:

  • Initially build the surface according to the plans. Fix obvious busts of three tenths or more.
  • Review the performance of the surface. I like to view slope arrows and create contours at a tenth of a foot which makes slope changes obvious and easier to fix.
  • Add breaklines to define the surface.

There is often a lot of time spent with small areas of a parking lot that are not working well. Experience will be the judge as to how much work it takes in order to meet the objective. Sometimes there just needs to be an extreme break over angle or varying slopes where you want a single one.

It is critical to remember how the surface is going to get from the screen to the dirt. A long grader blade is going to be making the undulations you have programmed into the file. Yes, the operator can rotate to make a narrower effective width, but it is important to consider this fact when building data.

Details

There are things we do that to me seem like a great way to increase speed and accuracy, improving margins. Here is a list of some the good and the bad:

  • Handicapped ramps. We can build a great handicapped ramp but I think common sense prevails. Machine curb will be run and the ramp cut out while the mud is still wet. We will give you linework so you know where to put the ramps but leave the curb full height.
  • Curb layout points. PC’s, PT’s, and radius points are a great way to layout hand built sections of islands and driveways. We will usually group the points by type so you can keep screen clutter down.
  • Saw cut line for turn lanes. When we get offsite plans, the existing road elevations may not be correct. Contractors will take good shots of the transition and send them off to us. We will build the entrance and propose changes in elevation where things aren’t right. We will forward that information to the engineers for approval.
  • Surface overbuilds. This is taking the outside edge of a surface three feet or more so equipment does not go out of design and need to reset wasting time. Newer control boxes are not a victim of this. If you are running older equipment then that’s OK. Don’t clutter up the screen with an overbuild if you don’t need it.

The take home message here is that data should look simple. The problem is that it takes a lot of work to make a simple looking surface. Machines and rovers have ten times the power and features than those from ten years ago. Use this to your advantage and leverage feature rich information. Your checkbook will thank you.

Using optical character recognition for data prep

Using optical character recognition for data prep

We have all been there. We come across a lot of numbers that need to be entered during a project. It could be spot elevations, alignment information or control. Life would get easier if we could just get the numbers from the page into our program!

In this post, I will cover two approaches to accomplish the task. Carlson has a solution that is outlined in this video as well as a walk through in the article. One of our talented engineers, Jessica Dugger, let me know about an online service that is reasonable and highly accurate. Her experience was with a raster .pdf and resulted in a highly accurate conversion. Several characters were interpreted incorrectly, but that was an easy search and replace fix in Excel. I will use a vector sheet to show the process in Convertio.

I used Bluebeam to breakout a sheet from a plan set for the demonstration. Nothing special, and this could easily be a table with a thousand points with equally huge coordinates.

Here is the coordinate table I want to convert. Just as a test, I converted the entire sheet with plan and profile as well. It did a great job with the text and actually brought in the plan view areas as a .jpg. This may help as well for an image to send with an inquiry.

The coordinates came in fine. I can now do some quick Excel editing to make it easy for my software to recognize. I will use the letter for the point name and use the full description.

You will notice the flags on the numbers and the Point name “O”. They were text and I converted them to numbers. The “O” was text, I ignored it to keep it that way. The file was then saved as a .csv for use in any software. Here it is in Trimble Business Center:

The foot indicator came in as a question mark, other than that, the import was easy and quick. We use tools like this to improve productivity and give our clients better value by saving time in managing data.

Carlson has a text conversion tool that does a good job. The prior example was really simple but the Carlson tool can come in handy with a lot of pages as it does not cost extra, or require you to be online for the conversion. We use it with jobs that require non-disclosure or are sensitive government work. Here is the process:

• Strip out the sheets to convert
• Bring them into Carlson as Linework

• Open the convert polylines to text command
• Create a new file name for the project
• Populate the characters you want to recognize

• Select and convert text.

Not to worry, I have done a complete screenshot video explaining the process below. The process is slow to set up and sometimes you will need to fix things in Excel doing a search and replace but overall the results will save you a ton of time!

How to Utilize the Point Offset Feature in Trimble Business Center

How to Utilize the Point Offset Feature in Trimble Business Center

TOPS engineer Mike Tartaglia walks you through the simple and easy task of taking detailed information from a PDF and placing it to create a working model using the Point Offset feature in Trimble Business Center (TBC).

The TBC platform is field-to-finish survey CAD software to help surveyors deliver high-accuracy GNSS data, create CAD deliverables and leverage full data traceability throughout a project’s lifecycle. TBC can do everything from sites and roads to point clouds and photogrammetry.

Update on LIDAR and Photogrammetry

Update on LIDAR and Photogrammetry

With the New Year well underway, I wanted to take a look and review the advances and advantages of current imaging technology as it relates to creating surfaces from LIDAR and Photogrammetry.

It appears that the more things change, the more they stay the same. Several parts of this world have made great strides while many remain slow to progress.

Drones

UAV platforms are cool, that is unless you have $38,000.00 in the air and it’s not responding to your request to come home. We need this device to do one thing; move a sensor in a predetermined pattern and image when requested and return safely for another use.

Prospective buyers have become focused on flight times, but the real number I always want to know is coverage and quality. A great camera with a proper lens can go high, fly for a short time and get the accuracy we are after. Once you know all the variables, the questions you ask will change.

Multirotors have idled in regard to advancement. Good motors, precision GPS and bigger more efficient batteries have allowed good flight times and safe operation. We use parachutes with our copters and feel comfortable sending them up.

Fixed wing platforms are split into two distinct camps, hand and wheel launch. The small, quick wings cannot carry good cameras and data quality suffers. The larger platforms need wheels and smooth ground but offer the benefit of carrying a larger sensor for better images. There is crossover in these types including hand launch/belly or parachute landing; the blurred line is offering some possibilities.

I am hoping this next platform gets proven soon, I like where it is going. The VTOL (Vertical Take-off and Landing) plane holds promise. Lift like a copter then fly high and fast with a big camera for a long time. Like any other platform, power is always the issue, to remedy this, some makers are putting gas engines to be used as thrust motors and even generators. I think we will have something worthy by year end.

Imaging

At this moment, the best solution for aerial topography is a full-frame sensor camera and a good lens. We can obtain good accuracy on a consistent basis. There are some improvements on the horizon that will help things.

When a drone flight is not possible due to regulatory restrictions, our trade partner Doug Andruik at Syn-Geo had created a two-camera pod he puts on the strut of a Cessna and effectively does close range photogrammetry with a full-scale aircraft. A great solution for large acreage or no drone zones.

We are all waiting until LIDAR becomes effective for use on a UAV. Several versions are out with fair accuracies and high price tags. Development is happening daily because of the great potential of the application. I’ll look at these and report as they become available.

Improving Accuracy

One of the best things to come along for improved close-range photogrammetry is precision GPS. The Applanix chips (Trimble) have made geo-referencing images more accurate and easier. When an image is correctly geo-tagged, post-processing is quicker and the resulting 3D information is more accurate. Combine this exacting geo-tagging and good images and accuracy gets much better. This makes our fieldwork more efficient and the results in the office better. In my opinion, this is the go-to solution; for now.

Processing

Pix 4D is still the easiest post-processing software, my issue is the same data-set run multiple times yields different results and residuals. As with any processing of imaging data, check to many ground control points to verify accuracy. UAS Master from Trimble is a robust application with the ability to fully incorporate precision GPS orientation from the Applanix chip. I use the software on a regular basis but am hesitant about training users. When you know how all the aspects of the program interface you can do some great things. When first learning post-processing, there are too many variables in the software to “just click a few icons” and get a result like in other applications. That Power can be a pain to use sometimes. Rumors are that there will be some easier workflows coming in future versions, I’ll keep you updated.

Wrap-up

Right now the best way to get reliable, consistent data is to fly a full-frame mirrorless camera with a high-quality lens using copter with an Applanix chip and post process in the software of your choice.

Always collect a TON of control/checkpoints so you know how good the results actually are. We earn our money back in the office slowly going over data, cleaning up the point cloud and shipping the client a good surface.

Profitable Implementation of CIM, Civil Integrated Management

Profitable Implementation of CIM, Civil Integrated Management

Proposal for presentation at Site Prep Tech

Marco Cecala, President, Take-off Professionals, Inc.

Summary;

The recent advances in technology for use in civil construction are impressive. The broad appeal of GPS, LIDAR, lasers, total stations and computers have provided the contractor with many opportunities. Contractors have embraced these advances, but not without difficulty during the learning process. Many have made technology a profitable part of their business, while others question the advantages.

This interactive presentation will answer questions and provide a strategy for establishing or streamlining your use of technology.

Equipment

  • Brief overview of current equipment types. GPS, Total Stations, LIDAR and field computers.
  • Best use for each type of technology.
  • What to buy, and when.

Training

  • What training options are available and their differences.
  • How to take full advantage of dealer, manufacturer and independent training.
  • How to identify key staffers for leading the technology push.
  • How to stay current with training as it relates to hardware and software upgrades.

Application

  • What to expect from the technology.
  • Implementation; gradual or all in?
  • Responsibility chain when using technology.
  • How the high tech job site differs from traditional grading.
  • The connected job site, how it can help profitability.

Work Flow

  • How technology changes job dynamics.
  • How electronic data affects a site.
  • How to effectively manage data from the office to the field.
  • Meeting requirements for the use of technology.

Marco Cecala is the President of Take-off Professionals. A Civil engineering consulting firm based in Phoenix, AZ. As the nation’s most experienced and largest firm of their type, they are uniquely qualified to work with contractors and engineers on projects of any size.

Their business involves preparing 3D models for machine control, quantity take-offs, training and consulting.

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