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<p>Martin</p>
<p>As a geologist and geophysicist it is extremely important for us
to be able to see below topography and inside (slice and dice)
volumes as in NVIZ in grass.</p>
<p>I have always thought that only being able to view topography
form the top or volumes form the outside not inside was called
2.5D.</p>
<p>I am wandering if you should differentiate between them.</p>
<p>it would be extremely useful for us to ab able to render 3D
raster from grass. Basically the same as in NVIZ of Paraview<br>
</p>
<p>thanks</p>
<p>Syd</p>
<p><br>
</p>
<p><br>
</p>
<div class="moz-signature">
<p><span style="font-size: small;"><strong>Syd (Sipke) Visser,
P.Geo.</strong><br>
<span style="font-size: small;">President, Snr.
Geophysicist/Geologist</span></span></p>
<p><span style="font-size: small;">
<span style="font-size: small;">
</span></span>
<span style="font-size: small;">Tel: 1 (604) 582-1100<br>
<span style="font-size: small;">Cell: 1 (604) 813-1440<br>
<span style="font-size: small;"><a class="moz-txt-link-abbreviated" href="mailto:sydv@sjgeophysics.com">sydv@sjgeophysics.com</a><br>
<span style="font-size: small;"><a
href="http://www.sjgeophysics.com">www.sjgeophysics.com</a></span></span></span></span></p>
<p><a title="www.sjgeophysics.com"
href="http://www.sjgeophysics.com">
<span style="font-size: small;"><span style="font-size:
small;">
<span style="font-size: small;">
<br>
</span></span></span></a></p>
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<div class="moz-cite-prefix">On 2017-12-14 02:41 AM, Martin Dobias
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAC2XbFeBXzT_Lw_xL=8-FFc51Eb0Rm+PELxmDtSaLzZbCb+Cbw@mail.gmail.com">
<pre wrap="">Hi Andreas
On Wed, Dec 13, 2017 at 3:31 PM, Andreas Neumann <a class="moz-txt-link-rfc2396E" href="mailto:a.neumann@carto.net"><a.neumann@carto.net></a> wrote:
</pre>
<blockquote type="cite">
<pre wrap="">Hi,
Being a caver, I have a lot of underground data. Thanks to the support from
Martin I got them to load correctly as 3D polygondata.
However, one issue I have is that the terrain rendering disappears when I
look below the terrain model surface - which isn't so nice for a caver or
geologist. Is this also an issue about culling? Would it be possible to
enable the rendering of the backside of the terrain surface?
</pre>
</blockquote>
<pre wrap="">
The fact that terrain from below is not rendered is a very common
optimization in 3D rendering called back-face culling - it makes
rendering faster by only rendering triangles that are facing camera.
It is not difficult to turn it off, but I am not sure if the culling
should be turned off by default...
</pre>
<blockquote type="cite">
<pre wrap="">The other issue I have is that tilting is somehow locked at the horizon. I
can look down on the terrain and then rotate the whole model until I look
sideway into the model, but than the rotation is blocked. I cannot rotate
any further so that my camera gets below the surface and that I could move
below the surface and look up towards the terrain. I guess this makes a lot
of sense for people who do not need to explore things below the terrain
surface, but for geologists or cavers, it would be great if this
rotation/tilting blocking could be disabled somehow.
</pre>
</blockquote>
<pre wrap="">
Yes this is intentionally locked (for now) as most users would
probably complain if the camera went below the horizon. I understand
you use case though - maybe we can have a underground/caver/geologist
mode for the 3D view that would both disable back-side culling of
terrain and also unlock camera rotation...
Cheers
Martin
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