View Issue Details
| ID | Project | Category | View Status | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 0001579 | FSSCP | physics | public | 2008-01-17 15:12 | 2012-11-19 16:09 |
| Reporter | Backslash | Assigned To | Goober5000 | ||
| Priority | normal | Severity | minor | Reproducibility | always |
| Status | closed | Resolution | won't fix | ||
| Product Version | 3.6.9 | ||||
| Summary | 0001579: Ships with null Moment Of Inertia rotate wildly | ||||
| Description | Ships with Moment Of Inertia values of 0.00000000000000000000 end up getting spun around for the tiniest thing -- a weapon impact, a shockwave, a collision. Goober's code change in ship.cpp of 2007/12/02 is apparently the cause. Of course modders should be doing their best to release models with proper data, but for those already released that are broken, not to mention campaigns using released models (example: Blue Planet), this causes quite a problem. | ||||
| Additional Information | The change is here: http://lists.game-warden.com/pipermail/fs2source-dev/2007-December/000371.html I just now tested, and the game does seem to behave properly without this fix. I'm guessing it ends up being the opposite extreme, that of ships being rock solid and unshakable. Don't know if there are any other bad side effects. Thoughts? | ||||
| Tags | No tags attached. | ||||
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I had mentioned this same thing to Goober in early December when I noticed it for the first time with on of the Orion models. That was right before I went into the hospital though, and I completely forgot about it until now. I don't believe that we ever did decide anything about this, but Goober would probably be the one to try and take care of this. It's a bug either way, but as you noticed, the "fix" kinda screws things up. We need to be able to generate a suitable MOI, but honestly, I don't think that anyone has actually figured out how Volition did it yet. |
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Yes, I've encountered this bug first time this morning. Are there any guidelines for the inertia values or are they based on pure guesswork? |
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I don't that anyone actually knows, hence the problem. To my knowledge no one has been able to figure out what formula Volition used to come up with their values. I'm assuming that it's all just guesswork for anyone that is using a real MOI for their models (in the case that they aren't just copying the values out of retail models anyway). |
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I've backed out the fix. But really, we need to figure out how to autogenerate moment of inertia. :-/ EDIT: Incidentally, comments in the code seem to indicate that it's generated by bspgen. Do we have the code for that, or do we know how that works? |
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I know that my calculations were seriously off, and I don't think that even Bobboau has been able to figure it out yet (based on various forum comments on the subject). Was bspgen ever even released at all? I did a google search and didn't turn up anything other than references to it. I don't remember it ever actually being released in source or binary form, only requests for it to be released, and notes from V that it would be released sometime after FS2 was. |
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Interesting. Perhaps we could ask daveb about that. Presuming the request isn't coming from Kazan, he'd probably be ok with it. :p I'll ask Inquisitor's advice. |
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AS a side note I just used PCS2 to generate the tensor, and the ships moved alright so I think for saga those values are good enough for at least the most ships. Problem is.. now FRED crashes. As soon as I enter any inertia tensor to a pof, FRED crashes with a win32 exception telling something about bad memory access.. there is some bug in FRED when it comes to reading the inertia tensor I suspect. Goober? |
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Since every other model in FRED works perfectly fine, I rather suspect that you did something wrong. |
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Tried it again to confirm now it works. But I don't know what I could have done wrong I simply pressed "recalculate MOI", confirmed, then saved the model. Hardly something you can do wrong. Maybe the saving didn't work. Edit: Nope.. still doesn't work. But the problem is not the tensor. PCS2 corrupts the model on save even if I don't change anything, just load and immediately change. |
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I have the same issue as KeldorKatarn when trying to open/save in PCS2, so I've been modifying the Inertia values in ModelView32. Trying to figure out what they are supposed to be based on mass and max velocity, but I don't know if that's the appropriate method. I already fixed inertia on Cargo03 in 1555, I would not mind correcting the Inertia values in the POF's if people are either A: willing to go with my figures or B: can suggest a best guess method of determining a "proper" inertia. I'd solve for A by using ships of approximate class and stats and then fiddling as necessary. |
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It seems that the retail behavior accommodates null MOI politely, but the "change in ship.cpp of 2007/12/02" is what caused odd behavior. That change was backed out around 2008/01/18. So the current behavior should be satisfactory, and any problems with MOI would be data problems in third-party mods. Therefore this can be closed. |
| Date Modified | Username | Field | Change |
|---|---|---|---|
| 2008-01-17 15:12 | Backslash | New Issue | |
| 2008-01-18 05:12 | taylor | Note Added: 0008818 | |
| 2008-01-18 05:12 | taylor | Status | new => assigned |
| 2008-01-18 05:12 | taylor | Assigned To | => Goober5000 |
| 2008-01-18 22:27 | Tolwyn | Note Added: 0008819 | |
| 2008-01-18 22:39 | taylor | Note Added: 0008820 | |
| 2008-01-18 23:00 | Goober5000 | Note Added: 0008821 | |
| 2008-01-18 23:01 | Goober5000 | Note Edited: 0008821 | |
| 2008-01-18 23:18 | taylor | Note Added: 0008822 | |
| 2008-01-18 23:21 | Goober5000 | Note Added: 0008823 | |
| 2008-01-19 00:33 | KeldorKatarn | Note Added: 0008824 | |
| 2008-01-19 07:37 | Goober5000 | Note Added: 0008827 | |
| 2008-01-19 16:17 | KeldorKatarn | Note Added: 0008828 | |
| 2008-01-19 16:24 | KeldorKatarn | Note Edited: 0008828 | |
| 2008-01-25 08:08 | Zacam | Note Added: 0008836 | |
| 2008-01-25 08:09 | Zacam | Note Edited: 0008836 | |
| 2012-11-19 16:09 | Goober5000 | Note Added: 0014079 | |
| 2012-11-19 16:09 | Goober5000 | Status | assigned => closed |
| 2012-11-19 16:09 | Goober5000 | Resolution | open => won't fix |
