Hi

On the basis of my experiments, it seems that the collision bubble/offset as perceived by the game online (it seems to handle it differently offline) is effectively a sphere centred on the reference point of the aircraft model - what a pity aircraft aren't spherical in shape...

Is this the case, or am I barking up the wrong tree? Arf, arf.

Also, does anyone know if there is an interaction between the damage boxes as defined in the dp file and the size of the collision bubble.

If the model collision bubble is reduced, will the game only read hits on boxes if they are inside the bubble?

Or, when the collision bubble is reduced, does this proportionately reduce the size of the damage boxes? It doesn't seem to do this, as guns etc remain in their correct positions after the bubble is changed, but nevertheless, there does appear to be some effect on the way the aircraft registers damage from hits. 

Any thoughts?

All the best

Pads

Isn't there a CFS.cfg tweak to fix this on all aircraft?

I also found an article on hex-editing the MDL of individual aircraft to fix that collision bubble. I'll see if I can find it.

Pads. Read this thread. Not sure if it will help. http://www.cfcforums.com/showthread.php?t=13837

The fix will depend on the aircraft. What works for the defaults might not work for 3rd party models. There are also 2 different types of 3rd party model used in CFS2, early ones created with FSDS1 & the later ones with FSDS2/Gmax. These might all need slightly different tweaks to fix this problem.

I've mentioned before that I've never flown online so I've not experienced this problem. I've always understood that the collision bubble is caused by somethiing in the MDL file. Providing the DP is accurate it should not affect anything. We had a long discussion on all this some time ago on this forum. I suggested all the methods I knew for the various types of model but nobody came back to confirm if they worked or not. It's difficult to do this without reliable feedback.

Right. I'll go through what I remember from the last time we discussed this. I spent a lot of time researching all this.

At first, the only way to fix this was with the CFG tweak Fireman mentions. I also found this on the RAF662 site. Quote:

Not sure if this works for all aircraft or just the defaults.

Then someone found out by accident that the FS2000 Tcsfview utility also fixed the collision bubble on 3rd party aircraft created with FSDS1. This will not work on the later CFS2 aircraft created with FSDS2/Gmax.

The RAAF lads worked on this & came up with their MdlEdit utility which works in the same way as Tcdfsview - only for the defaults.

Apparently Ivan Hsu's MDLC utility has an option for the later FSDS2/Gmax models.

That's about all I know about it.

Hi all,

Wow - what a lot I got...  

Thanks for all of this and all of those useful links, Hagar, everyone - you're stars!

I've actually got MdlEdit - and IMHO it is the best way to reduce the collision bubble for stock aircraft. I think a setting of 3 is the generally accepted one.

For other aircraft, I use MK_MDLC v2.0 (which Hagar suggested to me - an excellent program!) or a hex editor (I've got HexEdit and it does very nicely - http://www.catch22.net/software/hexedit.asp)

Using the Hex editor, the line in the mdl file that you need to change is 3040 - the first value in the line sets the model offset (collision bubble) - see screenshot below:



This is the stock Hellcat. You'll notice that the offset value has been set to '03' (corresponding to the value set in MdlEdit, which is how this one was changed). MK_MDLC allows you to set this value from 1 - 16, so is a little more versatile and can be used with non-stock aircraft.

This far I've got - largely due to the help of Hagar and the rest of you guys here at Simviation and also some of the fellows at Sim-Outhouse as well.

What I'm trying to find out is whether there is a relationship between the collision bubble and the way that the aircraft registers damage when hit.

This is an issue that has come out of my experimentation with those daft flyable ships I've been working on... (I can hear Hagar groan inwardly...

The ships are converted from default CFS2 mission object ships to aircraft using a modified .air file and aircraft.cfg. Everything else is straight from the box, mdl file, dp, etc.

These 'flyable' ships work beautifully as ships online - you can land them on water (carefully!), or CFO down to a water-based location, and then sail them around at a top speed of around 30kts. They are intended to serve as player-controlled targets in online bomb/strafing runs.

And they work very well indeed, apart from the simply enormous collision bubble, which seems to be around 550 to 600 ft from the model reference point. The bubble can be reduced using a hex editor in the manner described above, but this changes their effectiveness as targets. The default collision bubble setting is 8F (corresponding to 143 on a scale of 0-255, which in turn seems to correspond to about 550'-600' in game, assuming the bubble is centred around the model reference point and this value is the radius).

With the bubble left as default, the ships seem to register damage where they are hit - bow, stern, deck, bridge, superstructure, etc.

When the bubble is reduced to coincide approximately with the bow and stern of the ship, the way the ship registers damage changes as well.

Suddenly, it seems, the extremities of the ship no longer seem to register hits. It's as if the damage boxes have got smaller and so no longer correspond to the visual model of the ship, or those boxes outside or at the edge of the collision bubble are simply cut off.

I've tested this a good deal with squadmates and based on their reports and my observations in external view while 'under attack' this really does seem to be the case.

So, this is what I'm trying to work out - whether there is indeed a relationship between the mdl collison setting and the dp file (as there seems to be) and if so what that relationship might be?

BTW: I have posted two ships on our web site: http://www.caw15.com/downloads/ships.html

Both of these use the same model as the stock mission object ships and essentially the same dp (it has been edited to add guns - sadly the flak doesn't appear to work online), but the boxes, parts, etc are as per the default version). As I said, they work well, but they suffer from this over-inflated collision bubble. You're welcome to try them out.

Gasp. Time for a beer... Don't you love this game

~S~

Pads

Hi

Yes, this is very much an online issue - the game handles collisions differently in the offline context. You've still been a great help though!

The ship models, dps, etc., seem very much like stock aircraft implementations, I am sure they use the same principles and techniques - it would be very wasteful programming for MS to have to invent two ways of doing the same thing unless it was absolutely necessary.

If reducing the collision offset really does impact upon the way in which an aircraft registers damage online (as it would appear to), then unless everyone is using the same setting, players using the reduced bubble could be thought to be operating at an advantage...

As it is, I think most experienced online players use a reduced bubble setting of 3, so perhaps this is not so important.

Mmm - interesting stuff, anyway.

All the best,

Pads

Mmm.

The CDP file is automatically generated whenever an aircraft is selected (if it doesn't exist already, in which case the existing file is used instead) - it's something to do with the way that the game interprets the dp info on the fly during actual game play, but I'm afraid the details of how and why it works elude me too...

I think some online players cheat using the CDP file. They adjust their dp, generate a new cdp and then re-adjust their dp to default so that it is not picked up by Fair Skies. Something like that anyway.

I do update the cdp this is a matter of course when editing dp files, but I have specifically tried to do it after a model adjustment  - I'm not sure it will have any impact, but I will certainly give this a try.

Good thought!

Cheers

Pads

Hi

Yup, it's a funny one. I think the game must handle mission object models differently to aircraft ones, although it also seems to handle offline and online aircraft models differently, too. So may be it is doing the same thing to both aircraft and ship object models, purely dependent on the context - online or offline.

The Essex is 8F by default, so somewhat bigger than the Indiana (71).

Online, crashes occur at around 130' (or thereabouts) when approaching the Essex from the stern and bow, rather greater distances trigger collisions when the aircraft is diving in from above or approaching from the side. 

To get an approaching aircraft to register a collision pretty much as it touched the stern, I had to reduce the collision offset drastically. I don't have my figures with me at the mo', but I'll post them in when I dig them out.

I estimate the online bubble for the default Essex model to be around 500'-600' in radius, assuming it is centred on the model ref point, i.e., it extends around 100'-150' beyond the end of both bow and stern, rather higher (relatively) above the deck and bridge structures.

Bubbles for smaller ships are smaller, but collisions seem to occur in a similar manner.

This is all down to the difference with which the offline and online games handle aircraft collisions - I don't know why this is the case. But it's a massive pain the back-side... 

Ah, me...

Pads