Author Topic: Ovito Version 3.0.0-dev52 on Mac OS Sierra crashed during Tachyon rendering  (Read 101 times)

yidongxia

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I was running OVITO Version 3.0.0-dev52 on Mac OS Sierra. The type of data I loaded in is LAMMPS Data File. The program crashed during the rendering with Tachyon, even with not too many atoms. I was using Compute Property --> Transparency.

I have attached the Problem Report for Ovito below. Any feedback is greatly appreciated!

Alexander Stukowski

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Dear yidongxia,

This looks like a bug in the Tachyon renderer. Perhaps some sort of stack overflow. Can you reproduce the crash, or was it a one-time thing?

It it is reproducible, it would be great if you could post the input dataset together with a step-by-step description of how to produce the program crash. I am not the author of the Tachyon renderer code, but perhaps I am able to fix it if there is a bug. Otherwise I will forward the report to the developer of Tachyon.

Thanks.

-Alex

yidongxia

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Alex,

I tried several time, and I think it is very reproducible. The problem appears relatively independent of the LAMMPS data size and rendered image size (although I did not try very small data). I have attached as an compressed file for your diagnosis. The key step that led to the crash is very likely to be "Add modification -> Transparency --> set 0.9". Without applying the particle transparency, OVITO would not crash. Below are the complete steps to reproduce the crash:

* Download the attached file "out.dat.tgz" and unzip it to "out.dat".
* Load "out.dat" into OVITO version 3.0.0-dev52 on Mac OS Sierra.
* Uncheck "Simulation cell" under "Display" bar.
* Under "Particle types" bar, set the Radius of "Type 1" equal to 300.
* Add modification -> Modification -> Compute property -> In "Expression" bar, set value to 0.9.
* Set "Output image size" to Width 800 and Height 800.
* Switch render to "Tachyon".
* Click "Render Active Viewport".
* When waiting for the image rendering of the perspective view, hopefully you will see crash halfway of the rendered image.

The first time I saw this was when I was using Version 2.8. I did not try it on Version 2.9 because this version cannot be opened up (I saw a post that reported this issue earlier.) Eventually I started trying Version 3.0.0-dev52, which resulted in the crash too. There had been a gap of my Ovito usage continuity. I did not remember what Version before 2.8 was when I could do things without fail.

Thanks for your time looking into this!

Best,
Yidong
 

yidongxia

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Alex,

I further tested the problem with older Version 2.6.0 and 2.7.0 on Mac OS X Sierra. It turned out that Version 2.6.0 successfully rendered the image with the steps I described. However, Version 2.7.0 crashed. So I guess this problem, might have originated from Version 2.7.0. Hope this information may help.

Alexander Stukowski

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Thanks for the instructions how to reproduce the crash. They were helpful.

I was able to reproduce the error and I think I was able to fix it. The maximum number of recursions in the Tachyon raytracer was set too high, leading to a stack overflow at runtime when there are a many semi-transparent objects in the scene. I have reduced this limit from 1000 recursions to 50, without notable differences in the generated image. Now it seems to work without problems. The change is included in ovito-3.0.0-dev54 (macOS version now available on the website).

yidongxia

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Great. I have also tested OVITO 3.0.0-dev54 on Mac OS Sierra on my Mac Pro and MacBook Pro. Both worked without issue. Cheers!