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<p class="MsoNormal">Hi,<o:p></o:p></p>
<p class="MsoNormal">We are using VTK in a 3D LiDAR based mining automation application which operates continuously.<o:p></o:p></p>
<p class="MsoNormal">VTK in medical application is great but VTK controlling the world’s largest autonomous machine is interesting for engineering types.<o:p></o:p></p>
<p class="MsoNormal">If anyone is interested we can post some screenshots.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Many of the vtk developers will remember the vtk code impact of our original issue with overflow of ModifiedTime on a Win64 build.<o:p></o:p></p>
<p class="MsoNormal">Thanks again for the effort, it was certainly a relief as it was so critical for our application success.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Subsequent to the overflow fix the application has been running without issues on two system equipped with dual Xeon processors.<o:p></o:p></p>
<p class="MsoNormal">However one system with a four core i7 was having rendering issues at intervals of a week or more.<o:p></o:p></p>
<p class="MsoNormal">Our initial thoughts was that the issue was related to high processor loading.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">It turns out that the issue is related to ModifiedTime.<o:p></o:p></p>
<p class="MsoNormal">Rendering breaks if the PC time is changed in a negative direction.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">It took us some time to discover this.<o:p></o:p></p>
<p class="MsoNormal">The i7 system is running Windows 7 and the Windows Time service was in the Scheduled Tasks to run once a week on Sunday morning.<o:p></o:p></p>
<p class="MsoNormal">Vtk rendering only breaks if the time synchronisation has a negative correction.<o:p></o:p></p>
<p class="MsoNormal">This can be reproduced by manually changing the PC time backwards.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Q. Could this be resolved by making ModifiedTime independent of the PC clock.<o:p></o:p></p>
<p class="MsoNormal">We run a PLC (real time automation controller) in kernel mode on the same platform.<o:p></o:p></p>
<p class="MsoNormal">PLC’s are used in time critical applications such as motion synchronisation and use a SystemTime that does not jump.<o:p></o:p></p>
<p class="MsoNormal">I am not sure what mechanism the PLC uses but suspect that the time is initialised to the PC time on application start and then incremented at 100nS intervals (the timer resolution).<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Paul<o:p></o:p></p>
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