[osg-users] Tiny normals: osgviewer vs osgcompositeviewer

Per Nordqvist nordqvist at gmail.com
Mon Dec 4 08:45:50 PST 2017

Hi there, thanks for your quick input.

@Robert; The use case is pretty common: the original model assumes mm, I
assume meters. Hence the extreme scaling.
Yes I noticed the transforms are flattened, which is probably a good thing
in my case but it shouldn't
change the rendering. (The model is exported by a 3rd party software so I
don't have full control)

@Sebastian: Yes you are probably right, I thought that some normals were
completely lost though due to
the scaling (rescaling = division by 0) but maybe I was lucky this time.

Thanks again,

On 4 December 2017 at 10:38, Sebastian Messerschmidt <
sebastian.messerschmidt at gmx.de> wrote:

> Hi Per,
> Just a thought:
> Maybe the Optimizer simply applies normal-rescaling?
> Cheers
> Sebastian
>> Hi all,
>> I came across something strange recently;
>> the attached model is a red triangle scaled down by a factor 1000.
>> The normals are squashed and I see some rendering problems in my app,
>> which uses osgcompositeviewer.
>> Confirmed with
>> osgcompositeviewer red.osgt  - renders with white color (incorrect)
>> BUT
>> osgviewer red.osgt - renders with red color (correct)
>> I did some digging in the OSG code, it seems the difference is that
>> osgviewer always
>> optimizes the scene graph, something that osgcompositeviewer never does.
>> Adding an optimizer to osgcompositeviewer fixes the rendering.
>> So first question; would it be better if the two viewers applied same
>> optimizer settings?
>> Since users would expect them to display things in the exact same way.
>> Second and more interesting; how can optimizer correct a "broken" model?
>> Thank you!
>> /Per
>> _______________________________________________
>> osg-users mailing list
>> osg-users at lists.openscenegraph.org
>> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
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