Place the Georef Cam higher

[turban]

Sometimes I get black holes when I render the image:

This happens when there is a single peak that is higher than surrounding terrain. Is it possible to have the camera higher by default, so it's above all parts of the DEM?

[domlysz]

Thanks, fixed it in latest update. Please give it a try to confirm it's correct now

[turban]

The black hole is slightly smaller, but it is still present with the latest version:

[domlysz]

That strange the camera is placed 10 meters above the highest point of the mesh...

Maybee the subdivision level for the render is higher than the one for the 3view and there is no enough points around the pic to correctly estimate the maximum elevation of the rendering mesh.

I'will try to find a cleanest way to set the camera offset (I want avoid just setting an arbitrary value).

[kikislater]

I think it just a blender basic tip. Under Camera > Lens, Set clipping start = 0

[turban]

The clipping start is already 0 (or 0.001 to be exactly - if I try to change it to 0, Blender will change it back to 0.001):

[turban]

The clipping end value is 951.700 in Blender, but in my GeoTIFF it is 961.400 (retrieved with gdalinfo).

[kikislater]

Could you give us the blend or part of the blend ?

[turban]

This zip contains the GeoTIFF, the blend-file and the rendered image with the small black hole (left/middle):
https://dl.dropboxusercontent.com/u/2306934/MasterMaps/tile_13_09.zip

The black hole is "Himmeltindan" (964 m) in Lofoten archipelago: http://www.68north.com/outdoors/hiking-himmeltindan/

[kikislater]

Camera is very close to terrain in this part.
Modifiers : subdivision surface is set to 11, if you apply modifier or set to 9 black artefact disappear.

Place camera a little bit higher do the trick

[turban]

Seems to be the same issue as here: https://wanderingcartographer.wordpress.com/2014/11/14/shaded-relief-with-blendergis-part-2/

[domlysz]

So the problem come well from subdivision. Actually the script compute the mesh bounding box and place the camera 10 meters higher, but if the view subdivision is lower than render subdivision then in some case the computing bounding box will not reflect the final bounding box because view subdivision don't provides enough points to get a displacement in "full resolution"

In your blend file, higher point of the mesh is under the camera

But if I set view subdivision to 11 then the mesh is above the camera

[turban]

What about adding a camera height of 100 m rather than 10?

[domlysz]

yes but it's not a clean and general way to solve the problem, the difference between view bounding box and render bounding box can be of any value, most of the time it will be few meters or decade of meters but potentially it can be lot of more.

However, I'm afraid that it's not possible to estimate the resulting bounding box without increase the view subdivision value (witch can involve lot of ram). So, I think I will add an option to edit the offset when the user create the camera. Also, expressed this value as percentage of z dimensions will be probably better than raw meters.

[turban]

Sounds like a good plan :-)

[domlysz]

fixed 9bfbcb8

[turban]

Hi @domlysz, thanks for the fix - did you add an offset value and where can I edit it?

[domlysz]

You're right, I forgot to add a property for editing the value

Thanks

[domlysz]

Finally fixed this one !
49130af