The Evolution of Modeling in Construction

American suburbia is practically synonymous with cookie-cutter houses, carefully manicured lawns and winding roads. Another staple of these types of neighborhoods is the cul-de-sac. These road designs have been used in suburban planning for the better part of the last century, increasing in use alongside American car-ownership. While cul-de-sacs are necessary in residential planning, however, they pose significant challenges for those involved in the planning. In particular, designing a 3d model cul-de-sac can be difficult due to the unique geometry involved. For this reason, we’ll cover the basics of cul-de-sacs in city planning, how to draw a cul-de-sac in AutoCAD and how Take-Off Professionals can help simplify the process.

What Is a Cul-De-Sac?

The cul-de-sac has been a common feature of the American suburb since the mid-20th century. This French term translates to “bottom of the sack,” and is used to refer to a dead-end street where the only outlet is the entrance. These suburban road designs are a direct result of the American motor age, purposefully created to allow for more spacious property facades while simultaneously encouraging slower car movements.

Cul-de-sacs were first used in 1928 in New Jersey, but gained popularity in the 1950s as car ownership boomed. The design gained further popularity as engineering studies on residential street safety encouraged more discontinuous street systems like cul-de-sacs. These studies found that such designs reduced the number of motor vehicle accidents compared to grid-based designs, and generally encouraged safer driving practices. Both features proved to be highly desirable for the more family-centered residential neighborhoods.

How Are Cul-De-Sacs Designed?

While it is simple to describe a cul-de-sac as a dead-end street, there is much more that goes into the design. Cul-de-sacs vary in road length but are typically designed with wider-than-normal road widths to allow cars to park along the sides while still allowing residents to enter and exit. These roads may be even wider if driveways are placed along the roadway. The defining feature of the cul-de-sac, however, is the wide, circular termination. This termination is where most of the residential driveways are placed. Cul-de-sac terminations are typically 100 feet or more in diameter, which allows cars to easily maneuver in and out of driveways and service and emergency vehicles to turn around.

Cul-De-Sacs in Neighborhood Planning

Homebuyers desire cul-de-sac-based communities for their safer streets, neighborly environments and lower crime rates since criminals tend to avoid confusing street patterns that make for more difficult getaways. While these features make cul-de-sacs more desirable for residents, planners favor them as well. Here are a few reasons why:

• Reduced infrastructure costs: Cul-de-sac patterns require significantly less road and utility construction compared to grid patterns. Grid patterns require up to 50% more road construction and 25% more water and sewer line construction.
• Improved topographical adaptation: While grid patterns blanket entire regions with invasive infrastructure, discontinuous cul-de-sac patterns can be designed to work around areas that may be more topographically challenging or ecologically important.
• Decreased standards: Because they do not carry through-traffic, city regulations often do not apply in the same way to cul-de-sac-based neighborhoods as they do to grid patterns. As such, planners have less to worry about with regards to street widths, curbs and sidewalks.

These planning advantages make cul-de-sacs beneficial for home-buyers and a useful tool for neighborhood planners as well. For this reason, knowing how to design a cul-de-sac in 3D is a necessity for any construction design professional.

How Are Cul-De-Sacs Modeled?

Cul-de-sacs can be modeled with any AutoCAD software just like any other type of road. Using the data collected from a detailed topographical survey, planners can create a general plan for the roadways and cul-de-sacs. From there, professionals can then combine these plans into a detailed 3d model using AutoCAD software. Models should feature the cul-de-sac road, as well as any lots surrounding the cul-de-sac.

Cul-de-sacs can be modeled in several ways, but four primary features determine the overall shape and size of the cul-de-sac:

• Centerline curve: The centerline of a cul-de-sac is the centerline of the street leading to the termination. This centerline can be curved or straight, dictating the overall shape of the cul-de-sac road. The centerline curve is typically determined by the topography of the area and should be placed in a way that allows plenty of room between the road and any topographical features that will not be altered during construction.
• Terminal radius: The radius of the circular terminal is the distance from the center of the terminal to each side, and determines the overall size of the cul-de-sac’s terminal. For cul-de-sacs, this radius is a minimum of 50 feet, which results in a terminal that is 100 feet wide to allow plenty of room for emergency vehicles. The radius may be wider, especially if the cul-de-sac features a center island.
• Termination placement: The termination of the cul-de-sac is designed to be a circular shape, but this circular feature may be placed in various ways. A symmetrical cul-de-sac is designed with the circular feature placed straight on the end of the centerline, resulting in the traditional match-head shape of a cul-de-sac. Alternatively, a cul-de-sac can be designed with the circular feature offset up to 90 degrees from the end of the centerline, resulting in a terminal that curves to one side.
• Return curves: Placing a circular shape on the end of a rectangular road will result in sharp edges at the meeting points between the two shapes, which is undesirable for road construction. For this reason, the transition from the circular cul-de-sac terminal to the road is graded using return curves.

The above features are essential to know and consider while modeling for cul-de-sac neighborhoods and will come into play during the design process discussed below.

How to Design a Cul-De-Sac

Designing a 3D model cul-de-sac in AutoCAD is the most important step before initiating construction, as it creates a detailed plan to work from that can help streamline construction and minimize costly mistakes. However, cul-de-sacs are more difficult to design than normal roadways. One of the easiest ways to accomplish this model is by starting with a square and rounding off the corners to create a circle. This is a step-by-step guide for how to create a cul-de-sac with a rounded terminal using this method:

1. Draw the road: First, create the road section of the cul-de-sac. In AutoCAD, this will appear as parallel lines with no clear termination. Be sure to place the road in a way that goes around topographical features that will remain in the final construction.
2. Terminate the road: Draw a straight centerline across the end of the road where the circular terminal will be placed. Keep in mind that the terminal will extend past this endpoint by the termination radius, so allow enough room for the radius extending past this point. Make sure that the length of this centerline matches the diameter of the cul-de-sac, and place it according to the type of cul-de-sac you want to make. If creating a symmetrical cul-de-sac, place the middle of this centerline at the end of the road’s centerline. If creating an asymmetrical cul-de-sac, offset the new centerline as desired.
3. Create the terminal base: Using the centerline drawn in the previous step, create a square section of road with a width that matches the diameter of the desired terminal. This should result in a square section of road that approximates the shape and size of the final terminal. At this point, double-check the placement of the road square to make sure that the terminal placement is correct. Symmetrical cul-de-sacs should be placed so that all sides of the terminal are equidistant from the centerline endpoint for the main road, while asymmetrical cul-de-sacs should be offset to one side.
4. Create the junction: At this point, the AutoCAD software will detect a junction and should prompt you to create the return curves for the terminal. Enter the desired radius for these return curves — these should be fairly small, but keep in mind that the smaller the radius, the sharper the curve.
5. Round out the terminal: At this point, you are ready to change the shape of the terminal to a circle. Use the road tools and select the section of road you have created. Depending on the software you are using, you should have the option to either change the shape all at once or to select each corner and set a radius for a curve. Make the changes according to what your software allows.
6. Adjust terminal placement and junctions: From here, you can change the details of the terminal to match your desired plan. This may include moving the terminal from a symmetrical to an asymmetrical placement or vice versa. You can also change the radii of the junctions to create more gradual return curves.
7. Add grading: Once the overall shape of the cul-de-sac is complete, you can combine this design with a topographical map or manually change the vertical leveling of the model to match the topography of the construction project.

The above guide represents a basic method for modeling cul-de-sacs in AutoCAD that practically any construction planning professional can use, with some adjustments depending on the specific software. But we have yet to address an important question about modeling for cul-de-sacs — why is it so important to model cul-de-sacs accurately?

Why Model Cul-De-Sacs?

Construction sites used to rely solely on surveyor stakes, heavy-duty equipment and quality operators, but 3D modeling has brought about significant changes in the way residential areas are constructed. 3D models create more accurate layouts that precisely show what is needed for a construction project and can identify potential problems before equipment breaks ground. This careful planning minimizes project costs significantly by reducing errors and maximizing labor efficiency. This is especially important for residential cul-de-sac construction, which is highly affected by construction costs and is significantly inconvenienced by lengthy construction periods.

On top of the cost benefits of implementing 3D models in traditional construction, 3D modeling can be used in implementing 3D model machine control. If you’re not familiar with this concept, machine control uses positioning sensors on equipment to give machine operators real-time feedback during construction. These sensors tell operators how to position buckets and blades as well as target grades, which minimizes error and maximizes construction site efficiencies. When implemented correctly with quality 3D modeling, machine control can help achieve the following:

• Increased machine efficiency: By providing detailed feedback and instructions, machine control helps operators maximize machine efficiency and productivity.
• Decreased operating expenses: Because the equipment is used more efficiently, construction projects require less fuel and maintenance to achieve the same results.
• Minimized materials costs: 3D modeling allows for improved visualization of material usage, meaning that raw materials are used more effectively.
• Reduced surveying costs: Using 3D models and sensors, the equipment provides feedback about grades to operators, reducing the need for ongoing grade checking.
• Lowered labor costs: With more effective sensors, workers get real-time feedback that makes them more efficient, reducing the amount of labor needed for each project.
• Minimized errors: Real-time feedback allows workers to see their progress as they go and catches errors early, reducing the need for reworking areas.

The key to achieving these benefits for cul-de-sac projects, however, is using complete and accurate 3D models. This is why construction companies are increasingly choosing 3D machine control modeling services to help with their neighborhood construction projects. If you’re looking for quality modeling for cul-de-sac projects, Take-Off Professionals can help.

Work With a Data Modeling Expert

At TOPS, our specialty is preparing 3D models for construction sites of all types. With over two decades of experience providing 3D models for the construction industry and a talented team of engineers and technical staff, we have what it takes to transform your data into what you need to achieve your goals. We produce approximately 1,000 machine control models a year, and our clients can attest to our accurate, timely and detail-focused service. Best of all, TOPS has engineers working in all major U.S. time zones, providing timely service across the nation.

In addition to our high-quality service and staff, TOPS provides a unique platform for our clients to upload all their project files, notes and related documents. With this secure and user-friendly program, our clients can communicate with us effectively while still being able to focus on their core business. It’s all part of our dedication to a hassle-free client experience.

Contact TOPS today to learn more about the benefits of our services and how we can help with your next residential construction project.

New technologies are always disrupting the construction and civil engineering industries. Point cloud modeling has existed for a while, but it’s becoming a major tool for contractors and engineers who seek more ease and efficiency when conducting land surveys. It accomplishes the same work with fewer resources spent — which is what every person wants from their business endeavors. But what exactly is a point cloud, and how does it help with surveying work sites?

If you want to learn how to use a point cloud for 3D models, this article can show you how it works — plus what you can gain from it.

What Is a Point Cloud?

A point cloud is a collection of many small data points. These points exist within three dimensions, with each one having X, Y and Z coordinates. Each point represents a portion of a surface within a certain area, such as an engineering work site. You can think of these points similarly to pixels within a picture. Together, they create an identifiable 3D structure. And the denser your point cloud is, the more details and terrain properties you’ll see within your image.

Creating and utilizing a point cloud puts a world of data within your reach, but you must know what to do with it after you generate it. This question can pose a problem for some surveyors — and others may not know how to create a point cloud to begin with. However, both of these problems have easy solutions. When you outline the goals you want to achieve from using a point cloud, you’ll know how to obtain your data and get the most value from it.

You can create point clouds by using two primary methods — photogrammetry and Light Detection and Ranging (LIDAR), which we will discuss in more detail below.

How Is a Point Cloud Created?

How do you create a point cloud when it involves so much detail and so many small points? The answer is typically a laser scanner. Site surveyors can create 3D models from point clouds by using LIDAR lasers. With the laser, you scan a chosen environment — such as a construction site — and the scanner records data points from the surfaces within it.

Once you have the complete point cloud, you can import it into a point cloud modeling software solution. At this stage, you can modify the data points for better accuracy. To see the point cloud in a 3D format that resembles your terrain, you’ll need to export the data from your modeling platform and upload it into a computer-aided design (CAD) or building information modeling (BIM) system.

Using Photogrammetry for Point Cloud Surveying

Photogrammetry is a common method for creating point clouds. With this technique, a drone takes numerous pictures of a construction or civil engineering site. Because the drone uses a camera, you’ll likely need to adjust its settings for the site’s environmental conditions to get the best results. Various angles are required to capture a full view of the landscape. Once all the images are captured, you can use a processing platform to overlap the photos.

By stitching the images together, you can develop a point cloud, create a 3D mesh and produce a complete 3D model within a CAD or BIM program. The process of filling in the gaps between the data points and creating a mesh is known as surface reconstruction. That’s why it’s essential to get as many data points and images as possible — you’ll have fewer spaces to fill in or reconstruct.

In contrast to photogrammetry, remote sensing — which is what LIDAR is categorized as — uses aerial vehicles to study a work site and create data points from it in real time.

What Is a LIDAR Point Cloud?

With the help of drone technology, you can use LIDAR to scan an area and record its data points to produce a point cloud. LIDAR uses infrared light laser pulses to measure distances. When these pulses reflect back to the sensor, it measures how long it took for the light to return. These laser scanners can emit up to 100,000 pulses per second, which gives an incredibly detailed view of the area being mapped.

Once you’ve created your LIDAR point cloud, it goes through a similar process of being transformed into a mesh and developed into a 3D model. Mounting LIDAR hardware onto a drone allows you to use 3D laser scanning to map any area you choose. Attaching the hardware correctly is essential — incorrect setup can impact the drone’s balance, which affects your data’s accuracy.

LIDAR and photogrammetry produce similar levels of accuracy. When choosing which one to use, it’s better to consider factors like how long it takes to set up the equipment and which method will be easier for you to work with.

How Is a Point Cloud Used in Site Models?

What is a point cloud in surveying? Land surveyors use point cloud modeling to create expansive representations of landforms where it would otherwise require tremendous time and effort. Even if your project isn’t huge, using LIDAR drones to collect data increases your efficiency and overall work experience.

Civil engineering sites can consist of roads, subways systems, bridges, buildings and more, which can have complex structures. Surveying these locations manually can stretch out a project’s duration and require a bigger budget, but technological advancements like point cloud modeling streamline the process. In general, new technology has significantly impacted civil engineering within the last few years. Additive manufacturing, smart tech and artificial intelligence are just a few examples.

Drone technology and point cloud modeling could also become essential elements of the connected job site. Tasks like geolocation, transferring as-built information and remotely monitoring work sites can all benefit from these two technologies. In turn, companies can improve employee productivity and safety and reduce their insurance and liability costs.

Point Clouds in Earthworks

Point cloud modeling techniques use drones, which have become increasingly popular for earthworks and construction projects due to their flexibility and efficiency. They can fill multiple roles within the building process — from the beginning to the end of any project. Mining, surveying and agriculture are among the many industries that have adopted drone technology for process optimization.

Here are a few ways that drones have shaped modern earthworks jobs so far:

• Improved progress monitoring: Companies that commission earthworks projects don’t always have the time or resources to send people out to their sites to conduct regular checks. Drones enable them to inspect the progress by taking photos of the site and turning them into an orthomosaic. From there, they can use the orthomosaic to create a digital elevation model (DEM) and compare these daily shots to their final project plans.
• Better worker safety: Manual surveying may require workers to walk up and down steep slopes or through rough terrain, which can prove dangerous if someone falls. If you put a drone in the field instead, you can capture data from afar without the injury risk.
• Quicker cut-and-fill: Some companies use topographic surveys to do cut-and-fill comparisons, which can take days to perform on a large or complex work site. Processing the data adds more time to the schedule — but drones can accomplish data collection at faster speeds. Processing, importing and exporting this information using intuitive software becomes simpler.

Point Clouds Used for 3D Models

Constructing a 3D model can change in complexity depending on the building or landscape type and its features. Renovations or retrofits that must be done while the area is still in use add another layer of intricacy, but they are not impossible to do with the right tools. Laser scanners and high-tech modeling software solutions ensure that every possible object is identified and distinguished from the next.

For landscapes with complicated or richly vegetated terrain, it may be necessary to send a surveyor out to supplement any spots the scanner might miss. When you have your data points and begin the conversion from point cloud to 3D model, you’ll likely have more than one scan to work from. Similar to photogrammetry, you’ll need different angles of the same site to get the full picture.

Rendering the data into a 3D mesh organizes the points and sets a foundation that you can use to build a model. Exporting the point cloud creates a file that can be imported into a CAD or BIM system. What are the common point cloud formats? Depending on the software you use, you might see file formats such as:

• PTS: PTS is an open format for 3D point cloud data. Because open formats are maintained by standards organizations, anyone can use them.
• XYZ: XYZ is an archetypal American Standard Code for Information Interchange (ASCII) format. It’s compatible with many programs, but it has no unit standardizations, which can make data transfer more difficult.
• PTX: This is another common format for storing point cloud data, usually from LIDAR scanners. It can only be used on organized clouds — no unordered ones. It’s also an ASCII format.
• E57: This file format is vendor-neutral and compact. It can store point clouds and metadata from 3D imaging systems — like laser scanners. It’s also specified by ASTM International, with documentation in the ASTM E2807 standard. Additionally, it can store properties connected to 3D point cloud data, such as intensity and color.
• LAS: This open format is designed for data obtained from LIDAR scanning, though it can also accommodate other point cloud data records. It combines Global Positioning System (GPS) data, laser pulse range information and inertial measurement units (IMU) to create data that fits on the X, Y and Z axes.
• PLY: Known as the Polygon File Format, this type stores data from 3D scanners. It accommodates properties such as color, texture and transparency. It can contain data from both the point cloud and the 3D mesh.

Whichever file format you decide on, make sure your modeling software can convert your point cloud into one that’s compatible with your chosen CAD or BIM solution.

The Benefits of Point Cloud Modeling

Point clouds aren’t the only way to create 3D models, but they are incredibly beneficial for numerous reasons. Construction managers and civil engineers use 3D models for better machine control, improved accountability with project progress and true-to-life site layouts. Some of the perks of modeling include:

1. Efficiency

Uploading your point cloud into a photogrammetry platform lets you organize the data without the hassle of triangulating every point on X, Y and Z manually. The software does the work for you, which saves you hours of time you would have otherwise spent manipulating data. With these hours shortened, you can pull together the project details more quickly and begin your work sooner — which also means faster completion time.

Data collection is also faster because of the large number of points that can be recorded at once. A drone can sweep an expansive area in much less time than it would take for a surveying team to do the same.

2. Precision

Laser scanning and photogrammetry give quick and accurate results, transforming a living landscape into a detailed 3D model. Ground-based LIDAR can yield results that are accurate within a millimeter scale, while drone-based LIDAR is accurate from 1 to 30 centimeters. Its lasers can penetrate through dense vegetation for a more comprehensive site view.

Additionally, LIDAR often incorporates other features like GPS to ensure each data point comes with accurate information. Photogrammetry, too, uses Real Time Kinetic (RTK) geo-tags to ensure accuracy in recording the landscape’s form.

3. Savings

Because of the greater precision involved in site mapping with point clouds, you can plan a more effective budget for your projects. You can avoid going over your financial limit, and you’ll have fewer chances of running into any costly mistakes or unexpected expenses. Laser scanning also eliminates the need for manual surveying, which reduces the cost of hiring additional labor.

You’ll save money with these decreased or eliminated expenses, but you’ll also earn more on your projects. Your increased accuracy levels can lead more clients to trust you with completing their assignments, which boosts your reputation and encourages more companies to do business with you.

Work With a Point Cloud Modeling Expert

If you’re ready to incorporate point cloud modeling into your next engineering project, work with the experts at Take-off Professionals. We perform point cloud services and mesh conversions to help you process your data. Whether you’re working with a progress takeoff or an as-built, we can work with your information to provide the personalized results you need.

Working with a data modeling expert can help you save more money on your projects and finish tasks more efficiently. Conversion and processing require expertise and a fine-tuned eye for detail, which can lead to time-consuming mistakes if done on your own. By enlisting the services of our trained technicians, engineers and surveyors, you’ll receive results that have been refined by over 20 years of operation.

Fill out our form to learn more about how we can help you with your next job, or call us today at 623-323-8441. We do projects big and small, whether your point cloud consists of one construction site or acres of land.

The processes involved with building roads, railways and canals often involve adding or removing large masses of dirt and stone. This addition and removal of mass is called cut and fill in the excavation industry. Cut and fill is a common process where the movement of the earth is handled in a logical manner.

The goal of cut and fill is ultimately to conserve energy and maximize the use of existing materials to avoid bringing in or shipping out dirt mass. While common, it can be an exhaustive process — moving earth takes a great deal of labor, and mistakes can lead to costly rework. To avoid such problems, project planners use detailed and intelligent cut and fill maps, providing exhaustive plans to help guide excavation teams to the most efficient use of mass and labor.

What Is Cut and Fill?

So what exactly does cut to fill mean? Cut and fill excavation is also known as excavation and embankment. It’s a process where excavators move and place volumes of material to create optimal terrain for a road, railway or canal. The two terms are defined as follows:

• Cut: Earth that is removed from an area is considered “cut” or excavated earth.
• Fill: Earth that is brought into an area is considered “fill” or embankment earth.

When railways, roads or canals are dug out, the cut material is pushed to fill out nearby hills and embankments. This process is usually accomplished with earthmoving equipment. Bulldozers and excavators remove land from cut locations and transfer it to dump trucks, which carry it to fill locations. Once the land is transferred to the fill location, the filled earth is compacted with a roll-style or plate compactor.

This compacting process removes air before any construction takes place. It’s essential, as it prevents the earth from moving and settling during or after the construction process, which can damage the foundation and building features.

In cut and fill excavation, the ultimate goal is to conserve mass as much as possible. Having more cut than fill results in project managers needing to find somewhere to dump excess rock and soil, while having more fill than cut results in the manager needing to bring in dirt from another location. Both of these outcomes result in extra material, labor and equipment costs. To avoid bringing in or removing excess mass, cut and fill processes are planned in a way to keep cut mass and fill mass approximately the same.

While effective at conserving mass, cut and fill is an expensive process. The cost of this kind of excavation increases as more land is moved and more equipment and labor are needed to do so. To help maximize the use of earth, equipment and labor, site planners often use what is called a cut and fill map.

How Are Cut and Fill Maps Used?

When they’re planning areas where cut and fill is required, designers create drawings called cut and fill diagrams. These diagrams illustrate all the areas where cut or fill are required. Such maps are generated by taking highly precise measurements of the existing topography and elevation, then overlaying a map of the desired topography. In these maps, cut and fill are defined as follows:

• Cut: Areas where the existing elevation exceeds the desired elevation have the “cut” material.
• Fill: Areas where the existing topography lies below the desired elevation line are the “fill” spaces.

Cut and fill maps are typically created in two varieties. The most basic maps utilize 2-dimensional diagrams, while more modern solutions use 3-dimensional modeling software. These two options are explained in more detail below:

• 2-dimensional diagrams: At their most basic, cut and fill diagrams show a location along an X-axis with a positive or negative Y-axis, quantifying the amount of cut or fill with a negative or positive number, respectively. Since land exists in three dimensions, these diagrams must be created for multiple cross-sections of the landscape at regular intervals.
• 3-dimensional diagrams: 3-dimensional maps are more modern solutions for cut and fill excavation projects. The terrain is first measured using accurate surveying equipment, and the data points are used to create a software-generated model of the terrain. Once the base model is complete, the planner creates a model of the desired terrain and lays it over the existing terrain model to identify the cut and fill areas in three dimensions. Software models may highlight cut vs. fill areas with different colors that vary based on value ranges.

Choosing to use a 2-dimensional model over a 3-dimensional one should depend on the level of accuracy required for the project. Smaller-scale projects with limited cut and fill needs may not require more than 2-dimensional diagrams. Larger and more expensive projects, however, will usually require the accuracy provided by a 3-dimensional diagram. Beyond this difference, the ability to use one type of diagram over another depends on access to the site and equipment availability.

Terrain Features in Cut and Fill Maps

Cut and fill maps contain many of the same terrain features as traditional maps, though they often also include elevations for the purpose of calculation. Some of the common terrain features included in cut and fill maps are detailed below:

• Hill: A hill is defined as an area of elevated ground where the ground rises at a slope. Hills are shown on maps using contour lines that form concentric circles. The closed circle that’s smallest represents the hilltop.
• Saddle: A saddle is a low point between two points of high ground. It may appear as low ground between two hills or a break or dip along a ridge crest. This feature is typically represented on the map with an hourglass shape.
• Valley: A valley appears as a long groove in the land and usually contains a stream or river flowing through it. On a map, valleys are usually represented by contour lines in a U or V shape with the closed end pointing upstream. Draws are less prominent versions of valleys and are notated in the same way.
• Ridge: A ridge is an area with steep slope and high ground on one side. Usually, ridges will be shown with contour lines forming in a U or V shape with the closed end pointing away from the higher ground. Sometimes, spurs form from ridges, appearing as continuous lines of higher ground jutting out from the ridge. They’re noted similarly, though they may affect the shape of the ridge.
• Depression: Depressions are low points or sinkholes in the ground. Maps usually show depressions only if they are significant enough in size, and these features are notated by closed contour lines with tick marks pointing to lower areas.
• Cliff: A cliff is a sudden drop-off, appearing as a vertical or near-vertical change in elevation. Cliffs usually appear as contour lines being drawn extremely close together or on top of one another.

From the complete map, cut and fill can be planned around existing topographical features. Commonly, a map with these features may be used as a base, with the final project laid over it to determine areas of potential cut and fill. Once initial plans are made, cut and fill plans are added based on the topographical features.

How to Calculate Cut and Fill

So you’ve determined that you’ll need to use cut and fill excavation in your project, and you have an idea of what method you’ll be using. How do you calculate cut and fill area so that you can plan out the labor and calculate your project costs? The calculation method depends largely on the method you’ll be using in your project.

A number of software products are available for generating cut and fill maps, and many of them automatically calculate and optimize cut and fill projects. However, if you’re using more manual methods, a manual calculation may be required. A variety of calculation methods are used to calculate cut and fill values, and some of these methods are detailed below.

1. Cross-Section Method

The cross-section method of calculation is a common method used with the 2-dimensional method of mapping. With this method, cross-sections of the existing and proposed land levels are measured at regular intervals across the site. The cut and fill area is determined for each cross-section, then adjacent cross-sections are compared and the averages of their cut and fill areas are multiplied by the distance between them. This is done for each adjacent pair of sections, then the total volumes are added together to create the complete cut and fill volumes for the project.

The cross-section method of calculation is considerably more time-consuming than automatic methods of calculating volume, and the accuracy of the method depends on the distance set between sections. Closer sections result in greater accuracy but take longer to calculate, while further sections are less accurate but take less time to calculate.

2. Grid Method

The grid method of calculation involves drawing a grid onto the plan for the earthwork project. For each node of the grid, determine the existing and proposed ground level and calculate the cut or fill required. Once the cut or fill depth is calculated, multiply the value by the area of the grid cell. Do this for each square of the grid, then add the volumes together to determine the total cut and fill volumes for the project.

Like the cross-section method of calculation, the grid method takes time to implement and is significantly more time-consuming than any automatic systems. Additionally, the accuracy of the grid method depends on the size of the grid cell. Larger cells take less time to calculate but are less accurate, while smaller cells are more accurate but take more time to calculate.

3. Automated Methods

If you’re using an earthwork software, you may not need to use one of the manual methods above. Instead, the software will run the calculations for you. It should be noted that these software systems are faster but not inherently more accurate — for example, some software calculations are based on high-density versions of the cross-section or grid methods. However, automated systems often use more sophisticated calculation methods, such as the triangular prism method.

The triangular prism method is a common calculation method for earthworks, and it’s favored for its excellent accuracy. However, it must be completed using software due to its technical complexity.

The triangular prism method starts by triangulating the existing terrain to create a continuous surface of connected triangles. The same method is used to model the desired terrain. Once both surfaces are complete, the triangulations are merged to create a third triangulation. Once merged, the cut and fill is calculated by taking the volumes of the generated triangles and adding them together. Because of the excellent representation of both the existing and desired terrains, this method presents an excellent representation of volumes for cut and fill projects.

Work With the Data Preparation Experts

The cut and fill process is an extremely useful process for excavation in residential, commercial and roadwork projects. However, while cut and fill makes use of existing terrain, it requires detailed planning to be as effective as possible. To accomplish this goal, project planners need detailed cut and fill maps — that means they need survey equipment to get terrain information and software to process and visualize data in a meaningful way. Take-off Professionals can help.

Take-off Professionals prepares 3D models and performs related services for a wide variety of industries, from commercial construction to civil engineering projects. Our innovative data services are available to help take your terrain data and turn it into meaningful models that you can use for your next cut and fill project.

TOPS works with a wide range of systems, so we can provide services to as many companies as possible. We work with data from  Carlson, Leica, Topcon and Trimble equipment and can provide models in any format you need, whether your engineers use Civil 3D, MicroStation or another design software. We can even work with multi-brand fleets.

When you work with us, you can trust our decades of knowledge and experience as well as our innovative GPS and 3D machine control services technology. With our tools and services, your business can gain detailed insights into your project to help make the most of your cut and fill terrain.

Want to learn more about our models and how they can help on your next cut and fill project? You can get in touch with our team of data preparation experts right away by completing our online contact form or calling us at 623-323-8441.