Here's the image raytracing creates:
http://i.imgur.com/k1LXlCD.png
Notice the artifact line halfway down the image, it goes all the way across, it should not be there. All options for raytracing are enabled EXCEPT procedural textures, but that doesn't seem to affect it, saw with/without. All material properties are enabled.
From what I can tell, it shows up when you positioned the PCB perpendicular to the PCB face, ie looking straight down onto the board. When I tilted the PCB and rotated it, the line disappeared. The line appears in different places on the PCB, so it seems like an angle of view positional rendering issue.
Application: kicad
Version: (2017-04-05 revision bf21640ae)-makepkg, release build
Libraries: wxWidgets 3.0.2
libcurl/7.52.1 OpenSSL/1.0.2k zlib/1.2.11 libssh2/1.8.0 nghttp2/1.19.0 librtmp/2.3
Platform: Windows 8 (build 9200), 64-bit edition, 64 bit, Little endian, wxMSW
- Build Info -
wxWidgets: 3.0.2 (wchar_t,wx containers,compatible with 2.8)
Boost: 1.60.0
Curl: 7.52.1
KiCad - Compiler: GCC 6.3.0 with C++ ABI 1010
Settings: USE_WX_GRAPHICS_CONTEXT=OFF
USE_WX_OVERLAY=OFF
KICAD_SCRIPTING=ON
KICAD_SCRIPTING_MODULES=ON
KICAD_SCRIPTING_WXPYTHON=ON
KICAD_SCRIPTING_ACTION_MENU=OFF
BUILD_GITHUB_PLUGIN=ON
KICAD_USE_OCE=ON
You mean some white dots horizontal and vertical on the center of the image?
It looks to be precision related issues.
If that is the case, then it is related with the nature of the implementation.
Is that the center of the board only or on other parts / views?
It can occur on two cases I have in mind:
When you are looking with the view reset (looking for the center)
or it can happen when you are looking for a square of some plane.
The raytracing implementation splits the planes (zones) in small quads that are places one next to each other.
It may be because precision issues that some rays in some view are invalid evaluated.
If this is the case, it can help add some randomess to the rays but that cannot be full avoided.