Problem Open Orbiter RC1 - ISS Orbit Extending Automatically from Quicksave

[QuarksUnited]

Open Orbiter RC1 - ISS Orbit Extending Automatically when running the sim from a quicksave

I was doing an ISS dock mission and I did a quick save after sync orbit dtmin 0 and 2 orbit left to rendevous, when loading the quicksave and playing, again all values shows ok, but ISS orbit keeps getting longer, if i didnt pop out of ship view I can do all the steps and I can dock also, but then I will be miles away from earth, ISS also comes that spot , that's strange, 0 engines yet it goes to far distance both delta glider and ISS, anybody encounter same problem ?


this is where the position ends up after docking

 

[QuarksUnited]

Open Orbiter RC1 Quick Save

 

[Gondos]

Looks like you went into NaN space...
What build are you using ? (32 or 64bits)
Just to make sure, when that happens, open an Orbit MFD and look at the gravity contribution.
If it shows "G NaN" then that's the issue.
64bit build are sensitive to that, often because there are still some 32bit DLLs causing problems.

 

[QuarksUnited]

yes, I was using 64 bit, yes it shows G nan, just curious this G nan occurs only on loading quicksave or will it happen in realtime too ? (from launch without break to dock ISS ), in 64bit, and may i know what is this G nan any idea, anyway will try downloading 32 bit, thanks a lot

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[Gondos]

Thanks for the report
If you can confirm the behavior in 32bit it would be nice.
nan means "not a number", it's usually the result of invalid floating point calculations.
There is a protection in place (mostly for dot product->angle conversion) but it looks like it's not working consistently on x64 builds...
Edit: I get this randomly when flying the DG so it's not limited to quicksaves

 

[n72.75]

The issue should occur with 64 bit only.

The moons of Mars, Uranus, and Neptune, do not have source code, and so when orbiter "builds", them the build process is just copying them to a release folder. these were written circa 2005 by (I believe, not 100% sure) someone other than Martin, and contributed to him, sans source.

Because thse 3 dlls are 32 bit, when a 64 bit application tries to find something like the mass of a moon for a gravity calculation, it reaches into the DLL's export table, and because of the word length mismatch, ends up in the wrong place,and getting absolute garbage back for data. What seems to be happening is that this garbage contains things like IEEE-754 NaNs, and those poison the math in the body force calculation.

64bit Orbiter will be unusable until this is resolved. A temporary fix is to remove those moons from sol.cfg.

I am going to make a post that we can sticky in its own thread, because this keeps coming up, and it would be nice to be able to point people to one place.

 

[QuarksUnited]

Sadly 32 bit build D3D is not giving me a selection list



AMD Ryzen 3, VEGA 8 Graphics



May I please know this RC1 main release above 2 GB is 64 or 32 bit ?

 

[n72.75]

Sadly 32 bit build D3D is not giving me a selection list

View attachment 40495

AMD Ryzen 3, VEGA 8 Graphics



May I please know this RC1 main release above 2 GB is 64 or 32 bit ?

View attachment 40496

The upcoming release will be 32 bit only. Future versions will transition to 64 bit once we work out some issues with it.