Free and open-source geotechnical software covers a range of tools that require no licence fee: spreadsheets and calculation sheets, open-source numerical libraries and finite element codes, academic programs released by universities, free viewers and data utilities, and time-limited trial versions of commercial products.
These are not one category. A spreadsheet implementing Terzaghi’s bearing capacity equation and an open-source finite element framework have almost nothing in common except their price, and evaluating them together produces a misleading conclusion.
The useful question is not whether free software is good enough. It is what a licence fee actually pays for, and whether those things matter for the work in front of you.
Free software has a price. It is paid in engineering hours rather than licence fees, and the exchange rate varies enormously with the task.
What Is Actually Available
| Category | Typical form | Where it fits |
|---|---|---|
| Spreadsheets and calculation sheets | Published or self-built workbooks | Single-equation checks, teaching, verification |
| Open-source numerical libraries | Python and similar ecosystems | Research, custom analysis, automation |
| Open-source finite element frameworks | General-purpose solvers, often not geotechnical-specific | Research, specialised modelling |
| Academic and agency programs | Programs released alongside published methods | The specific method they implement |
| Free viewers and data utilities | Borehole log viewers, format converters | Data handling |
| Trial versions | Time-limited full commercial products | Evaluation before purchase |
Several of these are genuinely excellent at what they do. An open-source finite element framework used in research can be more capable than commercial software for the specific problem it was built to solve. A well-constructed spreadsheet implementing a code equation is often clearer and more auditable than a commercial module doing the same thing behind a dialog box.
The difficulty appears when a tool built for one of these purposes is used to deliver a commercial project.
What a Licence Fee Actually Pays For
Setting aside marketing claims, a commercial engineering tool provides a small number of concrete things.
Verified and Documented Methods
Commercial software states which method it implements, to which standard, with which assumptions. That statement is what allows a reviewer to check the result and an engineer to defend it.
Open-source code is verifiable in a stronger sense — the source is available. But verifying it is work, and it is work each user must do independently. A published implementation that has been checked by its author is not the same as one checked against benchmark problems and documented for a design office.
Code Compliance
Design standards are not only equations. They are partial factor systems, load combinations, design approaches, and detailing rules that interact in ways that are easy to implement incorrectly.
A tool that states compliance with a specific code has, at minimum, made those interactions explicit. A general-purpose solver applies the mechanics but leaves the entire code framework to the engineer, which is a substantial and error-prone task in itself.
Reporting and Documentation
Analysis produces numbers. A project requires a document that shows what was assumed, what method was used, and how the result was reached, in a form a checker or an approving authority accepts.
This is the gap most often underestimated. A calculation that takes minutes can take hours to turn into a defensible report, and that time is repeated on every project.
Design Beyond Analysis
Most free tools stop at analysis. A project continues into structural design, reinforcement detailing, drawings, quantity take-off, and documentation.
Where those steps must be done in other tools, information is transferred by hand — the point at which most errors enter, and the point at which a change to the analysis becomes expensive rather than trivial.
Support and Continuity
When a commercial tool produces a result that looks wrong, there is someone to ask. When an open-source project stalls, or the person who wrote the office spreadsheet leaves, continuity becomes the firm’s problem.
Where Free Software Genuinely Is the Right Choice
The honest list is longer than vendors usually admit.
Learning and teaching. Building a spreadsheet from an equation teaches the method in a way no commercial interface does. For a student or an engineer learning a topic, this is the better tool.
Verification of a commercial result. Independent checks are most valuable when made with a different tool making different assumptions. A hand calculation or a spreadsheet is ideal for this, and using a second commercial package is often less informative.
Single-equation checks. A bearing capacity check on a simple footing does not need a project environment.
Research and method development. Where the objective is to investigate behaviour rather than to deliver a design, open-source frameworks offer flexibility no commercial product provides.
Automation and data processing. Scripting borehole data handling, batch processing, and format conversion is a genuine strength of open ecosystems.
Evaluating a purchase. A trial version is the only reliable way to know whether a tool suits a particular office’s workflow.
Where the Economics Turn
The exchange rate between engineering hours and licence fees is what settles the question, and it moves sharply with three factors.
Repetition. A method implemented once and used once is cheap. The same method implemented once and used on fifty projects a year, each requiring documentation, is a different proposition. Commercial tools pay for themselves through repetition, not through capability.
Verification burden. Every calculation that goes into a design must be checked. A spreadsheet is checked once and then trusted — until someone edits a cell. Version control of self-built tools across a design office is a real cost that rarely appears in the comparison.
Liability. An engineer signing a design is responsible for it regardless of the tool used. Where a result must be defended to a client, a checker, or an authority, the ability to state the method, the standard, and the assumptions has value independent of whether the arithmetic is correct.
A tool is cheap or expensive depending on how many times you use it and how carefully someone has to check it.
An Honest Assessment
Neither category is inherently superior, and the framing of free against commercial obscures the real decision.
| Aspect | Free and open-source | Commercial |
|---|---|---|
| Licence cost | None | Recurring |
| Method transparency | Complete, if you read the source | Documented rather than open |
| Verification | Your responsibility | Vendor’s, checkable by you |
| Code compliance framework | Usually your responsibility | Usually included |
| Reporting | Build it yourself | Included |
| Design, drawings, quantities | Separate tools | Frequently integrated |
| Support | Community or none | Contractual |
| Best suited to | Learning, research, verification, automation | Repeated production work with documentation requirements |
Many offices use both, and that is not indecision. Spreadsheets for quick checks and independent verification, a production tool for project delivery, and open-source frameworks where a research question arises, is a coherent arrangement rather than a compromise.
Questions Worth Asking Before Choosing
- How many times a year will this calculation be performed?
- Who will check it, and what will they need to see?
- Does the output have to become a report, a drawing, or a quantity schedule?
- Which code applies, and does the tool implement its factor system or leave it to me?
- If the person who built this leaves, can someone else maintain it?
- Is the work being done to learn, to verify, or to deliver?
The last question separates the categories more reliably than any feature comparison.
Where SETAF2018 Fits
SETAF2018 is commercial software, and the case for it is specific rather than general.
It is designed around repeated production work: foundation analysis, excavation support, slope stability, ground improvement, liquefaction assessment, and the design, drawings, quantities, and reporting that follow. The methods it implements are established analytical, limit equilibrium, and numerical approaches rather than a general finite element framework, and the design checks follow EN 1997, TBDY, FHWA, and the Turkish excavation support regulation.
Two features address the gaps described above directly. Calculation reports show the equations, standard references, and intermediate values rather than only final results, which is what makes an independent check practical — including a check made with a spreadsheet. And drawings and quantity take-off are produced from the same model as the analysis, which removes the manual transfer step where errors enter.
Whether that is worth a licence fee depends entirely on the questions above. For an office delivering a handful of calculations a year, it is not. For one delivering foundation and excavation support projects continuously, the comparison is not between a licence fee and zero — it is between a licence fee and the engineering hours spent building, checking, maintaining, and documenting the alternative.
A trial version is available, which is the only way to establish which of those two situations applies to a particular office. Pricing for the wider category is discussed separately in the geotechnical software pricing guide, and the comparison with general-purpose finite element platforms in the guide to geotechnical finite element software.
Frequently Asked Questions
Is there genuinely free geotechnical software?
Yes, in several forms: published spreadsheets, open-source numerical libraries and finite element frameworks, academic and agency programs, free data utilities, and trial versions of commercial products. They differ enormously in scope and are not usefully evaluated as one category.
Can free software be used for real projects?
For individual calculations, verification checks, and research, routinely. For repeated production work requiring code compliance, documentation, drawings, and quantities, the engineering time required to fill those gaps usually exceeds what a licence would cost.
Is open-source software less reliable?
Not inherently — the source is available, which is a stronger form of transparency than any commercial documentation. The difference is that verification is each user’s responsibility rather than something done once and documented for everyone.
What does a commercial licence actually pay for?
Verified and documented methods, an implemented code compliance framework, reporting in a form checkers accept, integration between analysis and design deliverables, and support and continuity. Not, in most cases, better mechanics.
When is a spreadsheet the better tool?
For learning a method, for a single-equation check, and for independent verification of a result produced by other software. The last of these is genuinely valuable, because a check is most useful when made with a tool that makes different assumptions.
What is the real cost of building our own tools?
Development time, verification time, version control across the office, documentation, and continuity when the author leaves. These costs are recurring and are usually omitted from the comparison.
Should an office use both?
Frequently, yes. Spreadsheets for quick checks and verification, a production tool for project delivery, and open-source frameworks where a research question arises, is a coherent arrangement rather than a compromise.
How do I decide?
By asking how often the calculation will be repeated, what the checker needs to see, whether the output must become a report or a drawing, which code applies and who implements its factor system, and whether the work is being done to learn, to verify, or to deliver.
