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FSXA Crash box size

Dangerousdave26

Dangerousdave26

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us-ohio
Has anyone found out how to decrease the size of crash boxes so they are closer to the objects shape?

I am positive it can be done but realize that it might be something that we don't know how to do.
 
Arno will most likely know.

I have a feeling this is done at the XtoMdl level.

You can flag to remove crash geometry from parts of your model, so that XtoModel does not create crash geometry based on them.

At the end of the day though, the crash geometry control is a flag on/off feature for model parts when compiled. You cannot determine its size (AFAIK) apart from excluding parts of the model from the calculation.

Another thought ... you could detach "jutting out" objects from your model and compile it with those as separate objects, to see if the geometry is tighter.
 
I always thought you 'could' control the crashbox size, but its done at the object level, meaning, you have to edit all boxes for all objects in the scene... (unless I am remembering the sdk incorrectly)

also, I thought it was an extremely tedious process, so the process hcornea states is alot easier, by disabling them instead...

i could be totally wrong... but i seem to remember the sdk mentioning they are automatically made oversized, and need to be shrunk after modeling is determined... (but done at an object level, so its more than one needing fiddling...)

again i could be an idiot and thinking of something completely different. I always try to kill the boxes or state that crash detection need be turned off, as most of my hangars are openable, and taxiable anyways, and crashed are abound. honestly, I turn crash detection off (unless flying in the RTW, or Duenna trackable events) as I feel FS models crashes so incorrectly... I know when I hit something... I hate it when it records a crash when my wingtip is nowhere near an object and I loose a scenario for a questionable crash event.

BUT, I thought boxes could be edited, but its a pain on complex object groups...
 
Hi,

For FS2004 there was a tool to recalculate them, but for FSX I have never seen such a tool. So I don't think you can directly control them.

In ModelConverterX you can visualize the crashboxes as XtoMDL made them, that gives a good idea what is going on.

For most objects it should work quite good, although not always. But if you have multiple objects (and thus gaps in between) in one MDL, then the results will be more tricky.

What kind of object gives you trobule?
 
A group of aircraft carriers. The crash boxes are way too large around the Island on my model. I took a peek (with model converter x) at the default aircraft carrier in FSX and noticed that the crash boxes around its parts are very small. Even if tedious if I could find the way to do it I would reduce the size of the crash boxes around the Island. Ideally if you hit it the Island should cause a crash but the default size of the boxes mandates that they be removed.
 
Hi,

I am not sure, but would XtoMDL have an option to set how fine you want the crashboxes to be calculated?

Edit: by default you get this in the compliation log:

CRASHTREE no granularity specified

So that would indicate you can specify it somehow.
 
Last edited:
Hi,

I found it. There is an undocumented parameter: \CRASHGRANULARITY:1.0

The number is the granularity you want in meters. The crashbox is not always calculated exactly at that resolution though. It is minimal 8x8x8 cells and seems to increase in powers of two as well.

I have attached three pictures. The first is an object with the default crashbox. In the other two I specified the granularity at 1.0 and 0.25. The difference is quite obvious, but I haven't tested what the performance influence is.
 

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5 years out from RTM, and we're still learning new stuff.

Amazing work arno.
 
Yes, it is surprising how you can still learn new things.

I am wondering how many other useful hidden features XtoMDL might have :scratchch
 
Good stuff! I found out a while back that one problem I was having with crash box issues. It seemed to me that if one angles a building, the crash box elongates to accommodate the building without turning the crashbox. I have started leaving my buildings aligned with the grid and turning them with the XML file. That helped a good bit.
 
Hi Mike,

That is right. The crashboxes are aligned with the grid. So it is better to do the rotation while placing them. If you make the crashboxes at a finer granularity the error will be less, but it still makes more sense to rotate at placement.
 
I thought of a work around for the Island. Make a basic copy with lower poly and reduce it in size. Then simply add the crash box only to the inner model.

This will give you the performance your looking for, since it's an odd shape...

DG:eek:
 
arno said:
Hi,

I found it. There is an undocumented parameter: \CRASHGRANULARITY:1.0

The number is the granularity you want in meters. The crashbox is not always calculated exactly at that resolution though. It is minimal 8x8x8 cells and seems to increase in powers of two as well.

I have attached three pictures. The first is an object with the default crashbox. In the other two I specified the granularity at 1.0 and 0.25. The difference is quite obvious, but I haven't tested what the performance influence is.
Click to expand...

Yes sir that is what I was looking for. That is the same thing you see when you look at the default carrier.

Performance wise I can't expect that it would cause much of a problem when thinking in terms of carriers. There usually are not many other things around the carrier when at sea.

Thank You very much for looking into this.
 
Can i have some more detail on the use of the "\CRASHGRANULARITY:1.0" parameter.
The simple thing im looking for is: Where do i add this parameter?
 
Whatabout you talking here ?

Crash Box ??

I have in my fs the Option *Crash Detection* Off and have no trouble with this.
 
Hi,

littleMax said:
Can i have some more detail on the use of the "\CRASHGRANULARITY:1.0" parameter.
The simple thing im looking for is: Where do i add this parameter?
Click to expand...

It's a compiler option for XtoMDL. So if you are using GMax it is not really helpful. But I have also added it to ModelConverterX, so you can use ModelConverterX to change the crashbox of MDL files you made with GMax.
 
Bambi_007 said:
Whatabout you talking here ?

Crash Box ??

I have in my fs the Option *Crash Detection* Off and have no trouble with this.
Click to expand...

Yes, but not everybody does that. So I think a good developer has to make sure the crashboxes in the scenery he makes are OK.
 
arno said:
It's a compiler option for XtoMDL. So if you are using GMax it is not really helpful. But I have also added it to ModelConverterX, so you can use ModelConverterX to change the crashbox of MDL files you made with GMax.
Click to expand...
Yeah i know, and i use xtomdl (3dsM), so i simply ad it to the option in my link to xtomdl?
Cause im confused about the backslash, should that be a normal slash like in front of "/XANIM"
 
Ah, yes, I see I typed the slash wrong here. In ModelConverterX I use /CRASHGRANULARITY.
 
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