Introduction #

In Malaysia, the government has set a goal to widely adopt the Building Information Modelling (BIM) system in the construction industry by 2025. With BIM, information sharing is more efficient among all the parties involved in a project, from planning to maintenance and demolition. With such aim, engineers (mostly involving large or medium scale projects) will need to transform their design at the end of the day into 3D models and this can be achieved with the help of one of the Autodesk engineering software, Civil 3D.

While Civil 3D and AutoCAD may appear similar at first glance, Civil 3D is specifically designed for civil engineering tasks and has a wealth of specialized tools, including for sharing information. The downside is it’s not intuitive to engineers who are not already soaked in the AutoCAD nomenclatures. . With the large number of features and icons, it takes a significant amount of time to learn the software just to be able to create a single surface. Of course training classes are available online and offline, but then they can be costly; Another cons of Civil 3D.

These challenges with Civil 3D definitely open the doors for alternative software options, like MiTS. Our software offers ease-of-use, allowing engineers to complete their design within a single program without the need to navigate through hundreds of icons – something Civil 3D won’t or can’t do. Additionally, we have also taken the steps to promote interoperability and BIM in MiTS by developing a specific plugin called MCIntegrator, which enables back-and-forth synchronization between MiTS and Civil 3D.

Engaged users of MiTS may have come across or had the opportunity to experience this plugin before, where only utility networks and survey points groups are able to be synchronized between the two softwares. But in the latest releases, MCIntegrator has been upgraded to allow for the synchronization of platforms at two different levels, be it as surfaces (Civil Sync mode) or CAD objects (CAD Sync mode); greatly simplifies the conversion of platforms to TIN Surfaces in Civil 3D.

How does MCIntegrator simplify things? #

The Civil 3D design requires you to know about Surface, breaklines, boundaries, 3D points, 3D polylines, 3D faces… It’s quite a mouthful! With the MCIntegrator plugin, it eliminates all those steps and all you need to do is define the parameters for your design in MiTS and click ‘OK’ – the rest will be handled by the software. As simple as that, and you can have the work-life balance that you have always wanted.

Defining parameters will let the software know which information that needs to be written from MiTS to Civil 3D or the other way round. The parameters are listed below.

1. Surface feature – for survey points groups in MiTS and is available for two way synchronizations

2. Platforms feature – for conversion into surfaces in Civil 3D which is recommended for one way sync (from MiTS to Civil 3D) to prevent unwanted changes to your designed platforms. That is, unless you are synchronizing the surfaces in Civil 3D to a blank MiTS project file.

3. Utility features (Sewerage, Drainage, Water Reticulation) – to convert a network of polylines (in MiTS) into gravity or pressure pipes (in Civil 3D), and vice versa.

4. CAD settings – this features is for project that involves CAD sync level, requiring users to define the 3D View exported from MiTS

Parameter for MCIntegrator plugin

MiTS to Civil 3D: Platform Synchronization #

We have synchronized the platforms together with the slopes using the AllSurfaces method available for Civil Sync.

Results comparison: #

Sample project file here

	MiTS	Civil 3D	Discrepancy
Cut (m^3)	368505.36	380441.34	3.24
Fill (m^3)	28656.66	28090.25	1.98
Area (m^2)	103256.23	100171.86	2.99

Discussion: #

As shown by the results, the variations in cut and fill volumes between the two software programs falls within the standard industry range of less than 10%. While the outcome is considered satisfactory, our team’s innate curiosity prompts us to further investigate the cause of discrepancy despite the identical physical appearance of the TIN Surfaces in Civil 3D to the platforms and slopes in MiTS. The answer lies in the way Civil 3D and MiTS treat abrupt changes in the elevations or walls on altered terrains.

TIN Surface for human-altered terrain #

Many modeling softwares, including Civil 3D and MiTS, use TIN Surface to represent surface morphology. The surfaces will be created from the connection of irregularly spaced 3D points (with x, y, and z coordinates) by a series of edges to create a network of triangles to represent the land’s terrain. For you to get an accurate representation of your land’s terrain, denser triangles will be the best option, hence why it requires more scattered 3D points across your project. But then, there’s a catch to this; High density of points will create too complex surfaces that might not be useful for the computation.

For natural terrain, the job can be done quickly with TIN Surface. All you must do is create a surface and select all the 3D points – there you have a good 3D model representing the terrain. With minimal variations in the elevations and the use of survey points, users will have more control over the triangulation. Clearly the TIN Surface is geared towards these kinds of landscapes.

However, when dealing with human-altered terrains, TIN Surface can prove to be quite challenging to work with. Altered terrains often feature complex topography of flat or near-flat areas with abrupt vertical drops or walls in between the shared edges. With the terrains mostly designed as closed polygons instead of points, the complexity is not something that TIN Surface method can handle with its triangulation nature. Instead of presenting the vertical drop, it will straightaway connect the vertices to one another and show a smooth transition in between.

Well, this is what happens in Civil 3D whereby the earthwork quantities computation relies heavily on the TIN Surface and TIN Volume Surface. When it comes to altered terrain in Civil 3D, users cannot just simply convert the polylines with defined elevations into surface and have the software to represent the drops right away.  Your work does not end there – you will need to introduce a breakline to the TIN Surface – another feature that can help you but only if you really understand how it works. Now, imagine if you’re working on a project located in the hilly area; With more abrupt changes to the elevations for a flatter terrain, more breaklines are required which means more work for you.

Platform for human-altered terrain #

With the said limitation of TIN Surface, MiTS only uses this method for the pre-development stage, involving the survey points for representation of the terrain. For post-development (altered) landscapes, we offer a less complicated concept – Platform.

Platforms allow users to design or alter the landscape just as how their imagination is – be it regular or irregular shaped polygons –MiTS can handle them well.  

On top of that, with MiTS, users no longer must worry about the drops in between the polygons when it comes to earthwork volume computation; All of this will be handled by the software. What it needs is only on the platform level and sloping information from users to be able to generate the slope and compute the cut and fill. Hence, users can simply create the polygons with the levels defined according to the edges or the vertices and set the sloping direction to be in, out or none – and your job for the day is done.

The mismatch between TIN Surface and Platform #

Transforming platforms into Tin Surfaces is not a straightforward task, as the two entities are not the same. Attempting to fit platforms into TIN Surfaces can be achieved, but only with alteration to the platforms. There are certain mismatches and limitations that we need to be mindful of, that might impact the cut and fill results. 

TIN Surface doesn’t support abrupt drop naturally #

As an example, imagine two platforms side by side with 3m height difference at the shared edge. Once the platforms have been synced over to Civil 3D and transformed to TIN Surfaces, they will be truncated in a way that the vertical drop in between is simply ignored by the software when creating a network of triangles for the volume computation. Instead of showing the drop, the surfaces created would appear to be slanting at a certain level and have a smooth transition from a higher to a lower level.

By truncating or ‘cutting off’ parts of the platform, the volume computation will certainly be impacted as the surface area involved will also be different, leading to a mismatch between MiTS and Civil 3D.

Missing area #

There are times where areas are not properly converted from MiTS Platform to TIN surfaces, due to an inherent limitation in Civil 3D. To aid users in identifying the issue in their project, we have added a feature called ‘MiTS to Civil 3D Area Tolerance (%)’ in the Platform Civil Sync Parameters. This allows users to set a tolerance threshold and receive a warning message under the Action Panel if the percentage differences exceed the threshold value.

Users should take heed of the message, and add in the areas manually, so that the cut and fill volume can be preserved.

Civil 3D to MiTS Platforms Synchronization #

Under the Platform Civil Sync feature, users have the option to transfer TIN Surfaces from Civil 3D to MiTS by converting them into platforms. The conversion process will overwrite the existing platforms with individual TIN Surface triangles, resulting in a higher number of platforms that must be managed by users, however, the overall topology of the TIN surface will be preserved in MiTS

Does the conversion of the triangles affect the earthwork quantities between Civil 3D and MiTS? To determine this, it would be helpful to compare the results obtained.

Result comparison: #

Sample project file here

	MiTS	Civil 3D	Discrepancy (%)
Cut (m^3)	41769.44	41775.20	0.0138
Fill (m^3)	44431.93	44439.17	0.0163
Area (m^3)	61956.80	61956.83	0.0000484

Discussion: Why is there 0.01% discrepancy in my result? #

The results shown with discrepancy of only about 0.01% indicates that with the way how Platform concept works in MiTS in which users can throw in any shapes or vertical drops – the software will be able to handle the TIN Surfaces very well. Hence why the conversion is much easier compared to before.

The small and insignificant discrepancy on the earthwork quantities obtained in MiTS despite the identical physical appearance to the triangulation of the TIN Surfaces in Civil 3D might be due to the snap rounding algorithm for the platform input. The reason why you might also find verification errors – Platform MarkX is incomplete after the snap rounding, perhaps it’s just too small and can be deleted without affecting anything – when proceeding to compute the cut and fill volume for the synchronized platforms.

In MiTS, we implemented the snap rounding feature to increase the degree of accuracy for hand-drawn platforms, by ensuring the edges are connected to one another to avoid inaccurate earthwork computations. This parameter was set with a default value of 50mm in the software –we think this is already quite a good accuracy, but this value can be overwritten by users.

By overwriting to a small enough value up to 1mm will help in reducing the discrepancies in earthwork computation between MiTS and Civil 3D. This will also indirectly solve the verification errors obtained in your project file, though this may prolong the analysis process in your project file. You may refer here to understand more on the snap rounding and how it affects the volume computation.

Conclusion #

This article explains the concept of platform synchronization between MiTS and Civil 3D – via MCIntegrator– and demonstrates the accuracy of the transformation as well as the limitations