[osg-users] OSG-based excavator simulator

Paul Martz pmartz at skew-matrix.com
Wed Apr 20 08:11:13 PDT 2011

Hi J-S -- It looks great. But I do have a couple questions.

How flexible is your art pipeline / rendering process for loading arbitrary 
models? Could you replace that excavator with some arbitrary CAD machinery, such 
as a tractor, and get the same visual fidelity? Or is there quite a bit of 
per-model hands-on modeling time in the art pipeline to create the necessary 
specular and normal maps, dirt, scuff marks, etc?

Also, how are you doing the transparency (e.g., the excavator cab windows)? Is 
that simple RenderBin back-to-front rendering, or are you using an 
order-independent technique? If the latter, how are you implementing it?

Are the trees in the background simple billboards, or truly 3D so that the 
viewpoint can be placed inside them?

Is the atmospheric scattering simple OpenGL fog, or something more complex?

I didn't notice any screen-space post-rendering effects (such as depth of 
field), is that correct? If I'm wrong, what screen-space effects are you doing, 
and did you encounter any difficulties with generalizing them into your 
rendering system?

I'm always looking for more general ways to make stuff like this work, so I'm 
just trying to figure out how much of this demo was general-purpose, and how 
much was non-general, suitable only for demos.


On 4/19/2011 9:41 AM, Jean-Sébastien Guay wrote:
> Hi all,
> I just wanted to give you guys a heads up about a prototype project we worked on
> lately, and which I think looks great. There's a video of it on our YouTube
> channel:
> http://www.youtube.com/user/vortexsim#p/u/1/RhJR0qQJfAQ
> (set it to 1080p if you can)
> We did that demo in 3 weeks (2 people for graphics and physics programming, one
> modeler for the excavator model).
> Quick list of effects specific to this project:
> - Normal mapping
> - Specular mapping
> - Reflection mapping
> - HDR (using osgPPU)
> - Soil uses hardware instancing for the many small rocks
> - Mound of earth uses vertex texture fetch to render the height field (displace
> vertices, calculate normals in vertex shader)
> - Dust particles rendered with soft particle technique (depth buffer test) to
> avoid hard edges
> It's the most GPU-intensive simulator we've ever done, and it looks great, and
> it's OSG-based, so I thought I'd show it to anyone who's interested. :-)
> While you're on our YouTube page you can have a look at the other cool things
> we've done in the past, the offshore and port crane simulators are recent
> projects and are very nice as well (and they use osgOcean :-) ).
> http://www.youtube.com/user/vortexsim#p/u/9/KBGr74TMTrU
> http://www.youtube.com/user/vortexsim#p/u/0/dZeQ-eBrBDk
> Thanks,
> J-S

   -Paul Martz      Skew Matrix Software

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