Re: [osg-users] Clamping models to an osgTerrain

[Chris Hanson]

Most of the time, when it gets to adding stuf on top of the terrain, I head
over to osgEarth.

I think it's possible to serialize pre-built terrain models from osgEarth,
but I don't know if it is really feasible to do it to the extent that VPB
does.

On Thu, Jan 9, 2020 at 12:25 PM Brad Colbert  wrote:

> Robert, thank you for the reply.  The community-crickets were a little
> disconcerting.
>
> I don't think it has to be as complicated as you described.  Simply
> finding the height at the location of the object, placing it there, and
> placing a file reference within that tile's hierarchy so that the model
> file is paged in (or not if it's already in the cache).  Do this for every
> tile in the hierarchy and you are done.  That would be a major jump in
> capability, at this point.
>
> Either way, I'm simply looking to do the above and wondering if it appears
> feasible with current capabilities.
>
> Best,
> Brad
>
>
> On Thursday, January 9, 2020 at 1:41:25 AM UTC-8, Robert Osfield wrote:
>>
>> I don't know of any off the open sourced tools that do this for you.  It
>> was always something I had on my wish list for VirtualPlanetBuilder but
>> never had the time/funding to tackle it.
>>
>> The post processing of paged database is something that has been done
>> over the years for various purposes.
>>
>> Combing the TerrainTile height fields with cultral data - trees, roads,
>> houses would require one to positioning of the cultral data to the
>> appropriate height, then meshing the tile's height field taking into
>> account the outlines/points of the cultural data being added if you want an
>> exact match.  The remeshing will be the hardest part of this work, so I'd
>> suggest tackling the positioning first then add the meshing later.
>>
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Re: [osg-users] Clamping models to an osgTerrain

[Brad Colbert]

Robert, thank you for the reply.  The community-crickets were a little 
disconcerting.

I don't think it has to be as complicated as you described.  Simply finding 
the height at the location of the object, placing it there, and placing a 
file reference within that tile's hierarchy so that the model file is paged 
in (or not if it's already in the cache).  Do this for every tile in the 
hierarchy and you are done.  That would be a major jump in capability, at 
this point.

Either way, I'm simply looking to do the above and wondering if it appears 
feasible with current capabilities.

Best,
Brad


On Thursday, January 9, 2020 at 1:41:25 AM UTC-8, Robert Osfield wrote:
>
> I don't know of any off the open sourced tools that do this for you.  It 
> was always something I had on my wish list for VirtualPlanetBuilder but 
> never had the time/funding to tackle it.
>
> The post processing of paged database is something that has been done over 
> the years for various purposes.  
>
> Combing the TerrainTile height fields with cultral data - trees, roads, 
> houses would require one to positioning of the cultral data to the 
> appropriate height, then meshing the tile's height field taking into 
> account the outlines/points of the cultural data being added if you want an 
> exact match.  The remeshing will be the hardest part of this work, so I'd 
> suggest tackling the positioning first then add the meshing later.
>

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[osg-users] Unwanted Culling in 3.6.4 vs 3.5.1

[Anders Backman]

Hi all.

Another issue I discovered with 3.6.4 is that we now suddenly get unwanted
culling.
At first it looks like a small feature culling thing (which we disable at
global level with:

  // Don't do small feature culling
  osg::CullStack::CullingMode cullingMode =
m_viewer->getCamera()->getCullingMode();
  cullingMode &= ~(osg::CullStack::SMALL_FEATURE_CULLING);
  m_viewer->getCamera()->setCullingMode(cullingMode);


However, this does not look like a small feature thing to me at all.
Actually, it culls even when you get close to the objects.
Attached are two osgt-files.

One is saved from OSG 3.5.1 (works as intended).

Second one is saved from OSG 3.6.4 (where we get the unwanted culling).


If you use a later version of OSG (3.6.4) the one from 3.6.4 generates lots
of warnings:

CullVisitor::apply(Geode&) detected NaN,
depth=nan, center=(0 0 7.125),
matrix={
-nan(ind) -nan(ind) -nan(ind) -nan(ind)
-nan(ind) -nan(ind) -nan(ind) -nan(ind)
-nan(ind) -nan(ind) -nan(ind) -nan(ind)
0.187249 -0.470484 -6.20285 1

whereas the one from 3.5.1 does not.

Anyone give me a hand on this? I am really stuck.
I was first totally into small feature culling, trying to dig up old code
where people was trying to disable small feature culling on subgraphs etc.
But that is not the issue here.

Any suggestion would help. I tried to make the scene as small as possible.


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Re: [osg-users] How to realize volume rendering for medical use

[Robert Osfield]

I don't have time to look at your application right now, so have to provide 
some high level comments.  

The osgVolume NodeKit was written for volume rendering, and the effect you 
are looking for will be achievable with the right settings.

First up the blending of the volume texels is done based on the alpha 
value, in your transfer function you have an alpha of 0.0 or 0.6, I'd 
recommend that you try a gradient to see what results you get.

The OSG's tf plugin provides a native transfer function ascii file format 
that can help you set up and experiment with different transfer functions.  
the file format is in the form:

 # comment
 intensity r g b a
 intensity r g b a
 intensity r g b a

You can pass in transfer functions to the osgvolume example via --tf 
myfile.tf



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Re: [osg-users] Clamping models to an osgTerrain

[Robert Osfield]

I don't know of any off the open sourced tools that do this for you.  It 
was always something I had on my wish list for VirtualPlanetBuilder but 
never had the time/funding to tackle it.

The post processing of paged database is something that has been done over 
the years for various purposes.  

Combing the TerrainTile height fields with cultral data - trees, roads, 
houses would require one to positioning of the cultral data to the 
appropriate height, then meshing the tile's height field taking into 
account the outlines/points of the cultural data being added if you want an 
exact match.  The remeshing will be the hardest part of this work, so I'd 
suggest tackling the positioning first then add the meshing later.

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