Tebis 3.5 for design

21 October 2014

Tebis is rare amongst software applications for design, doing things that more mainstream offerings simply do not. Al Dean investigates one of the industry’s best kept secrets and finds a system that has much to offer, now and in the future

Product Tebis 3.5
Company name Tebis
Price on application

If you’ve not come across Tebis before, it’s both the name of the company and the set of solutions that it offers. Founded in Munich in the mid-1980s, Tebis has been developing CAD/CAM focussed tools.

Tebis’ interface

Over the years it has gained a wide spread of customers, including the usual set of household names such as Jaguar Land Rover, BMW, Ford, Honda, Audi, Daimler, Toyota, Opel, Volvo, Bentley and Aston Martin.

As you’d expect from a system that is focussed on CAD/CAM, much of the effort has been placed on taking complex part data and preparing it for tooling or die design and eventually machining, whether at the OEM level or within their inherent supply chains.

That said, the system has also found a home in other areas, whether that’s prototype machining, model making or after market components.

We’re going to split the review into two parts. In this issue we’ll be concentrating on the tools for design. Whether that’s creating data from scratch or, perhaps more appropriately, taking data from other systems and preparing it for manufacturing.

Next month we’ll cover the manufacturing portion of the system.

User interface

As you’ll have spotted from the screenshots that accompany this review, the Tebis user interface (UI) isn’t what the majority of users would expect from an advanced CAD/CAM system. But this shouldn’t be construed as a negative.

Yes, the Tebis UI doesn’t conform to today’s interface standards and it does show the system’s UNIX roots, but once you dig into it, you’ll find that it’s both logically and clearly laid out.

Across the top of the window, there is a series of modelling tool links — these switch between the different modules in the system. While they’re useful, most of the action is found in the panel of icons to the right of the interface.

This panel contains the generally applicable tools at the top — those that you’ll use the most, such as move, rotate, scale, trim etc. Below this are the selection filters. You’ll find a set of tools for each module then file operations.

Finally, you have a keyboard like input into the system. While, for the design part of this review, this seems a little odd, but when you consider that the same user interface is intended to be used on the shopfloor, it makes much more sense.

Another key area to consider is the data organisation tools to the upper left hand of the modelling window. This is key to ensuring that your data is organised, using layers.

While the use of layers has fallen by the wayside in many of the mainstream solid modelling systems out there, they’re an incredibly powerful tool when you’re dealing with models that could have hundreds, if not thousands, of surfaces.

The ability to quickly select, organise (by layer, naming conventions and colour) is particularly critical in a system like Tebis and mastering this will pay dividends further down the line, particularly when using some of the more complex operations, which we’ll come onto shortly.

Modelling power

At this point, it’s worth considering how Tebis works at a fundamental level.

Essentially, the bulk of the system’s modelling tools are non-history based (we’ll get onto those that are a little later on). For those used to the likes of SolidWorks or Autodesk Inventor, this might seem a little old school, but when you consider the environment Tebis is most typically used in, it makes sense.

Mould and die design is often a disconnected process. The tooling or part suppliers will receive the 3D data for the part (along with the usual array of 2D documentation) and are tasked with preparing that data for tooling.

That’s a vastly different process that used to do the design and engineering work. Essentially, the data comes in a dumb, non-intelligent manner and there’s not the huge requirement to track and trace history.

Systems like Tebis are geared up for tearing into that data, preparing and adapting it for core/cavity design, which can be accomplished without the history overhead. It differentiates between surfaces (untrimmed surface forms), faces (trimmed surfaces) and surface sets (a collection of faces that form a model).

As you’d expect, the system comes with a range of translators, covering not only the usual standard formats (IGES and STEP), but also a fair range of native formats, from the likes of Inventor and SolidWorks as well as Unigraphics/NX, Catia (covering V4 and V5), ProEngineer/Creo, JT as well as mesh based formats like STL and NASTRAN.

While we don’t have space to detail every single operation in the core of Tebis, it can be said that the system has all the tools you’d expect. From repairing and healing the imported geometry to creating new geometry from scratch.

Additionally, it’s worth noting that those tools also include all manner of capability in terms of splitting, joining and reconstructing geometry.

When it comes to this type of work, that’s often down to repairing, splitting and reconstructing complex geometry. As a result, Tebis has all the tools you need, including curvature continuous curves and surface patching, to get that data just how you need it.

Working with scanned data

Another area that’s not too common amongst the mainstream is the ability to work with laser scanning devices.

Tebis lets you take mesh data and create clean surface models

Tebis allows you to both import polygon mesh data directly from your hardware or to connect directly with digitising software, such as Faro or Steinbichler. Whichever route you take, the capabilities are the same. Those that have worked with such hardware will be aware that the results are often patchy in places.

Whether it’s to repair damaged areas of the scanned part or to fix issues with the scan, you have access to a range of tools that allow you to firstly repair the scan mesh (with hole filling, surface patching), then to convert it into surfaces where needed. And that’s where our next set of tools comes into play.

Advance surface design (ASD)

While the tools we’ve discussed so far work in a non-history based manner, there is a growing set of tools in Tebis that enables you to take advantage of history tracking while you’re making edits and building geometry.

The ASD module enables you to work with surfaces, whether you’re building them off that scanned data already prepared or constructing geometry from scratch. It allows you to find areas where surface patches can be created (typically across areas of lower curvature change), then use a set of tools to construct surfaces that match and patch in between those surfaces.

Here, I’m thinking about transition surfaces, areas where the radius needs to be maintained as well as tangency and curvature. The point here isn’t necessarily automotive style class A surfaces (though the system does the full G3 continuity), but rather getting to a workable result as fast as possible to a suitable degree of quality.

Morpher

The Morpher tools are found within the BREP module and again take advantage of the history tracking, but are focussed on taking a specific set of geometry and adapting them to specific conditions.

The reason I’m being vague about the use of this tool is that it’s incredibly powerful and its application to a single specific example shouldn’t be construed as a limitation of its usefulness.

That said, you can’t explain an operation without delving into a workflow — so let’s detail how it’s used to adapt a set of surfaces in a stamping die to account for spring back in a part.

Tools you need are there to check on deviation during surface adaptations

You begin with the ‘as designed’ set of surfaces, then start to define the morphing operation to achieve the form you want. As you might expect, this is wizard driven, but only as a way to move you through the process, rather than a fully defined and locked process. This means that adaptations and edits can be made at any point and the workflow stepped back into.

The first step is to set-up that ‘as-designed’ surface model. You work through the model and define areas that are locked (those which can’t move), those which are allowed to move, but not change shape and finally those that are allowed to stretch and twist into position.

The next step is to choose the morphing method you want to use. There are a number of morphing operations available and you can use one or several of these to stack up more complex edits to that geometry.

The concept is that you can use any of these methods to define how a set of surface geometry is adapted to new conditions. These include rotational constraints (to adapt a form for twist), using linear moves (to account for stretching of components), to points (defined using either manual input or from a hard probe digitising arm) or to a scanned model or STL.

Essentially, you link the ‘as designed’ model to the new shape, how it’s allowed to move and the reference in terms of morphing — and let the system work its magic. What you’ll then have is a set of cohesive surfaces that have been adapted to the new requirements. Of course, there’s a full set of analysis tools to compare the two forms to check tolerances and deviation — using both shading and numerical feedback.

Each morph operation has a specific set of inputs and requirements, but the goal is to take complex surfaces and adapt them to new requirements. This is something that, in other systems, would require a lot of wrangling. Using the morph tools lets you adapt those pretty rigid forms in a couple of operations.

Conclusion

We’ve barely scratched the surface of what Tebis can accomplish in terms of geometry handling, repurposing and adaptation. But what I hope this review shows is some of the areas of the system that aren’t too mainstream, that support the specialist requirements of its users and how those users are driving workfl ow development.

Tebis is used in a number of complex environments — complex in terms of geometry but also the inherent time pressures. It’s about getting to the next step (typically machining) in the shortest time possible but also to the highest quality possible. It’s also about handling complex operations. The perfect example of which is modelling compensation for spring back in stamping die. That sort of thing simply couldn’t be done in mainstream systems.

Some users may look at the UI and baulk somewhat. If you’ve never used a UNIX based system, then it’ll feel alien to start with. But the point is that it’s an UI that’s evolved over the last three decades to place the tools you want at your digital fingertips.

This could also be said to be true of the ‘lack of history in many of the systems’ modelling tools (apart from those we’ve fl agged up), but again, the workflow that this type of system is most suited to doesn’t necessarily need history — it’s much more freeform than that.

Dive in, rip the geometry into the parts you need, reconstruct it where required for the downstream process, repair it where needed and finish the job — then get it on the machine.

In terms of modularity, the system is indeed highly modular. Not to the extent of some, but there’s a clear path from the base modelling tools and translators, then expanding capability. But, of course, while Tebis is clearly a strong surface modelling system, what really makes it sing is that you use the same UI and data model to move that geometry into production.

We’ll be exploring Tebis’ manufacturing related tools next month. We’ll look at the workfl ow that takes the often complex and commonly problematic part geometry from import, through generation of stock models and into the programing of clean, efficient toolpaths. Of course, we’ll also explore some of the simulation tools that allow you to reduce testing and get straight to work.

Comments on this article:

I don’t care what anyone claims—that interface, is ridiculous.

Posted by Kevin De Smet on Monday 27 2014 at 10:03 AM

how do you scale data equaly in all directions and making sure it remains in the center?

Posted by useni mulima on Wednesday 10 2014 at 02:38 AM

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