Boosting 3D graphics in Creo 2.0

12 June 2012

To help bring Creo Parametric’s graphics engine up to date, PTC turned to AMD for some help. Transparency will never be the same again, writes Greg Corke

It’s almost criminal that there are some 3D CAD packages out there that aren’t making the most of the powerful workstation-class Graphics Processing Units (GPU) on offer.

Transparency in Creo Parametric 2.0 using ‘Blended mode’

Using ‘OIT, it’s easier to perceive depth

Large assemblies clunk around on screen simply because the software’s graphics engine hasn’t changed in years. Meanwhile, much of the GPU sits idle, rather like a Ferrari’s V12 engine on London’s M25 in rush hour.

But who can blame the developers? It’s impossible to be a specialist in all areas of CAD software development. The optimisation of 3D graphics is best left to the experts, right? This is why boffins at AMD have been spending time under the hood of many of the leading 3D CAD/CAM applications.

The AMD FirePro Professional graphics team has helped optimise the graphics engines inside CATIA, SolidWorks, Vero and EdgeCAM. Now it’s the turn of PTC and a close collaboration between the two companies has led to a big increase in performance in PTC’s new Creo Parametric 2.0.

Increased performance with VBO

Vertex Buffer Object (VBO), a specialist feature of OpenGL, is nothing particularly new. It’s been used to boost performance in SolidWorks and CATIA for some time now, but has now been implemented in Creo Parametric 2.0.

VBO works by storing data in GPU memory, so it can be rendered easily by the GPU. This significantly reduces the role the CPU plays in the process, helping boost performance.

Prior to VBO, Creo Parametric used ‘Immediate mode’, a rendering method that stores the model in system memory and loads data to the GPU on demand.

This process is slower, not only because it means lots of data needs to be continually transferred across the PCI Express bus, but the GPU sometimes has to wait for the CPU when it’s busy performing other tasks.

But how much quicker is the new VBO technology? AMD reckons it can improve 3D performance by an impressive 400% (compared to Pro/E Wildfire 5.0 (non VBO).

VBO is switched on permanently in Creo 2.0 and will benefit all display modes. While AMD claims the technology is optimised for its cards, it’s not restricted to AMD FirePro. Nvidia Quadro will also support the technology out of the box.

Order Independent Transparency (OIT)

Real time transparency is great for visualising transparent materials such as glass, but is also useful to help reveal details inside a complex assembly. This could be a car, for example, or an enclosure that houses electronic components.

Creo Parametric 1.0 had two transparency modes – blended and stippled – but performance wasn’t great and the way models were rendered sometimes made it hard for the user to perceive depth. Assemblies could look flat and, in some cases, objects were rendered out of order, meaning a part that was located at the rear of an assembly could actually appear to be at the front.

Blended mode (which is still available in Creo 2.0) starts, with the CPU and, before passing data onto the GPU, uses it to calculate the order in which semi-transparent objects are rendered. This process is not always accurate and needs to be repeated every time a viewpoint changes.

Order Independent Transparency (OIT) is a brand new transparency mode for Creo 2.0. Everything is done on the GPU and objects do not need to be ordered before they are rendered.

This not only results in much faster rendering time – four times faster than ‘blended mode’ in Creo Parametric 2.0, according to AMD – but the transparency effects improve clarity.

It’s easy to see where semi transparent objects overlap – and there are no ordering issues.

OIT is currently only available on AMD FirePro cards, a benefit of the joint development work between AMD and PTC. However, it’s likely that Nvidia Quadro cards will support this in the next release of Creo Parametric.

Conclusion

Trying to navigate around a giant assembly that jerks at your every mouse movement is no fun and a serious barrier to productivity. With VBO Creo 2.0 users now have the potential to work freely with models that simply ‘jerked’ too much before. Likewise, OIT could introduce users to the benefits of working with transparency, a display mode that may have been previously dismissed due to inconsistent results and poor performance.

Of course, when it comes to benchmarks, I tend to be a realist. Performance figures published by graphics card vendors always feature benchmarks and models that have been selected to show off technology in its best light.

While some models will exhibit increases of 400%, the reality is others won’t. It depends on your data. But having seen live comparisons between Pro/E Wildfire 5 and Creo Parametric 2 using a variety of models it’s clear this is a massive leap for PTC’s modeller, which brings it bang up to date in terms of 3D graphics.
www.fireprographics.com/creo

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