MAXSURF past. present and future

MAXSURF  23 was released at the end of last year; 2021 marks the 25th year of MAXSURF on Microsoft Windows whilst its predecessor MacSurf, on the Apple Macintosh platform, was first released in 1985. The developers behind the MAXSURF software are by and large naval architects and structural engineers, many of whom have been working on MAXSURF since the early days on the Windows platform (I started working for Formation Design Systems, as it was then, back in 1998). Over the years many things have changed, but we remain a dedicated core of developers working to give you the best naval architecture design software we can produce. We are quite a small team and sometimes, when perceived from the outside, it can seem that new features take a long time to see the light of day. Sometimes ‘enhancements’ are not necessarily apparent from a user’s perspective: making the software compatible with a different rendering technology; or refactoring the code to make it easier to maintain; but these tasks are fundamental to being able to add new features to the software. We continue to develop MAXSURF’s capabilities, particularly with regard to modeling and hydrostatic analysis and hope to have at least one release annually over the next few years. To give you an idea of what we have been up to, here are a few of the highlights that have been delivered in the last few versions of MAXSURF.


Over the years, the functionality of the ancillary modules have been integrated into MAXSURF Modeler: Fitting (aka Prefit) for NURB surface fitting; Link (aka Hydrolink) for export to different file formats; and most importantly Workshop, for defining primary structural parts (plates, decks, frames, etc). This integration improves productivity and simplifies the use of the software.

We have also been striving to improve the workflow from Modeler to Multiframe and it is now possible to export structural models created in Modeler with meshed plates, frames, decks and longitudinal stiffeners into Multiframe for analysis.


In recent versions of MAXSURF we have extended what you can do with models comprising of meshed surfaces. MAXSURF uses ‘trimeshes’. A trimesh is a list of 3D nodes connected to form a meshed surface of linked triangles. The use of trimeshes potentially makes it far simpler to model existing vessels for hydrostatic and hydrodynamic analysis because it is no longer necessary to first create a NURB surface model of the hull (which can be quite time consuming and difficult to do).

Models can contain a mix of NURB and trimesh surfaces and you can select which elements of the model should be used for each type of analysis. For example an existing hull might be modeled as a trimesh from imported CAD data and different alternative appendage designs can be modeled from scratch using NURBS surfaces. Furthermore appendage variants could be kept in the same, single model file but only selected appendages used during analysis.

There are many different ways of generating trimeshes: basic geometrical primitives such as cylinders, boxes and multi-stage circular cylinders; meshed NURB surfaces; imported from external data; fitted to a point cloud; etc. Of course a lot of the trimesh commands are also supported in the MAXSURF COM automation interface and this lends itself to automatically generating parametrically defined models, such as offshore floating platforms.

The ability to mesh NURB surfaces and also structural parts can be used to generate models for analysis in FEA and CFD software. Since all these tools are integrated into the single Modeler module, it is easy to generate models of different mesh density from the same basis NURB surface geometry.


Feedback from users has shown that hydrostatic analysis and producing data for stability books is one of the main ways in which MAXSURF is used. We are continually adding to the stability criteria calculations so that all the checks required by class can be done as efficiently as possible. We have also introduced new calculations including: MARPOL oil out flow; water on deck; cross-flooding; spilling tanks and partial flooding, over the last few versions.

Results are stored in a SQL database and can be processed for report generation without the need to redo the calculations. The use of a Microsoft Word report template also speeds up the process of creating the final report. We still have some way to go and there are several new features we wish to add to further improve MAXSURF’s reporting capabilities.


Often small changes to the software can dramatically improve usability and productivity. We try to simulate as many user workflows as we can and use this knowledge to make these types of changes.

We get a lot of constructive criticism and suggestions from users. We value this information highly and where appropriate, use it to guide the development of MAXUSRF’s new features. Sometimes we get many similar suggestions which we then distill into a workable feature – so if you make a suggestion, you may not necessarily see it in the software in the precise form that you envisioned. However we do take note of all the feedback we receive, so please, keep it coming.

More information

MAXSURF product page:

Bentley Offshore youtube channel:

This PDF file contains a list of the main new features which have been added in the last few versions MAXSURF:

For the latest version of the software, go to the Software downloads page (current Bentley subscription required):