Fixes and stuff by adfriz · Pull Request #1439 · leezer3/OpenBVE

adfriz · 2026-10-02T12:46:17Z

assorted fixes and stuff, Maybe useful, if needed can be cherry picked

leezer3 · 2026-10-02T12:52:12Z

 										} else {
 											CarWidth = a;
-											CarExposedFrontalArea = 0.65 * CarWidth * CarHeight;
+											CarExposedFrontalArea = 0.6 * CarWidth * CarHeight;


OK, that's really odd...

Looking back at the original source code from Michelle, the same mix of 0.6 and 0.65 values are used there.
This feels intentional, I'll have to try digging a bit...

i just follow the double CarExposedFrontalArea = 0.6 * CarWidth * CarHeight; at line 246 it was set to 0.6 , idk why it set to 0.65 later in the end...

but if im not mistaken this just a variable for air resistance calculations right?

Yeah, see my later reply after doing some digging in the decompiler....

leezer3 · 2026-10-02T12:53:03Z

 							}

-							if (Arguments.Length >= 6 && Arguments[5].Length > 0 && !NumberFormats.TryParseDoubleVb6(Arguments[2], out contactHeight))
+							if (Arguments.Length >= 6 && Arguments[5].Length > 0 && !NumberFormats.TryParseDoubleVb6(Arguments[5], out contactHeight))


Yep, looks like copy + paste typos...

leezer3 · 2026-10-02T13:32:58Z

OK, really interesting....

Running BVE4 through the decompiler shows it's not actually using the car width / height/ unexposed frontal area figures at all- The BVE to BVE5 convertor also similarly ignores them.
BVE2 is a bit more difficult to look into, as it's not .Net or VB.

Digging around looking for a copy of the BVE2 train editor at the minute.

Using the 0.65 figure rather than 0.6 gives approximately a 10% increase in wind resistance.

At the minute, I'd actually be more inclined to use the 0.65 figure in the first calculation (where width / height not set at all) and update the documentation with this, simply because a majority of stuff is going to have set the car width / height figures, and thus 'used' the 0.65 number....

…mats Not supported by BVE, may contain junk data, so disable when hacks on #1439

adfriz · 2026-10-02T13:52:21Z

OK, really interesting....

Running BVE4 through the decompiler shows it's not actually using the car width / height/ unexposed frontal area figures at all- The BVE to BVE5 convertor also similarly ignores them. BVE2 is a bit more difficult to look into, as it's not .Net or VB.

Digging around looking for a copy of the BVE2 train editor at the minute.

Using the 0.65 figure rather than 0.6 gives approximately a 10% increase in wind resistance.

At the minute, I'd actually be more inclined to use the 0.65 figure in the first calculation (where width / height not set at all) and update the documentation with this, simply because a majority of stuff is going to have set the car width / height figures, and thus 'used' the 0.65 number....

that unexpected, i thought BVE Trainsim use most of that stuff...

should i change both exposed and unexposed as named constant? maybe it easier to read than putting the value inline

leezer3 · 2026-10-02T13:57:18Z

More interesting yet:
BVETS train editor for BVE2 doesn't add them either.

Looks to me as if they're an OpenBVE addition, just not documented as such....

leezer3 · 2026-10-02T14:03:20Z

should i change both exposed and unexposed as named constant? maybe it easier to read than putting the value inline

To be honest, you might as well leave them alone at this point, other than us standardising on either 0.6 or 0.65 (will require an errata note too....) :)
I have done a conversion of the train.dat parser to block format here:
#1361

Haven't merged at the minute, mostly as converting the object parsers caused so many bugs...
It does have the advantage though of getting that to a clean licence state.

adfriz · 2026-10-02T14:03:21Z

More interesting yet: BVETS train editor for BVE2 doesn't add them either.

Looks to me as if they're an OpenBVE addition, just not documented as such....

if that code from the old era, maybe michelle was known bve2/4 at the time didn't have correct calculation and just add it?

adfriz · 2026-10-02T14:06:07Z

should i change both exposed and unexposed as named constant? maybe it easier to read than putting the value inline

To be honest, you might as well leave them alone at this point, other than us standardising on either 0.6 or 0.65 (will require an errata note too....) :) I have done a conversion of the train.dat parser to block format here: #1361

Haven't merged at the minute, mostly as converting the object parsers caused so many bugs... It does have the advantage though of getting that to a clean licence state.

alright.

you can cherry pick other commits if needed, especially the copy paste typo above.

leezer3 · 2026-10-02T14:41:04Z

Another point of reference, the earliest saved copy of the original documentation contains these values.
https://web.archive.org/web/20100516145131fw_/http://openbve.trainsimcentral.co.uk/develop/train_train_dat.html

I can't find any mention of them in the developer logs from the old page though:
https://web.archive.org/web/20080501074027/http://openbve.zxq.net/

Sadly the archive didn't save any of the linked source code...
I've got a lot of stuff kicking around, but no really early source code for the sim.

#1439

adfriz · 2026-10-02T15:33:49Z

didnt expect to get merged this soon, but thanks.

leezer3 · 2026-10-02T15:46:53Z

Fixes are a lot easier than new stuff.

adfriz added 13 commits October 2, 2026 13:47

Fix 14 copy-paste logic bugs in route and train parsers

38e5b9f

Replace repeated route error-location text with At() helper

6e70669

Replace repeated panel and train error-location text with At() helpers

6f4280e

Name unit-conversion constants in route and train parsers

c506d5f

Merge repeated X/Y/rotation offset blocks into ParseOffset helper

216080c

Merge repeated comma-pair blocks into TryParsePair helper

da9a66e

Merge brightness and element-delta formulas into helpers

43ee982

Merge repeated day/night image blocks into TryLoadImage helper

a30e9c8

Point command-line time parsing at the shared Time helper

a6a0863

Split Colors.cs into one file per struct

5e3a2fc

Move Menu dispatch and drawing into partial files

e88cf51

Split TrainBase into physics, movement and messages partials

bf9cf3b

Dispose the save dialog in RouteViewer messages

ce7e9d8

leezer3 reviewed Oct 2, 2026

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leezer3 added a commit that referenced this pull request Oct 2, 2026

Change: Don't attempt to read width, height etc. in old train dat for…

0e509cd

…mats Not supported by BVE, may contain junk data, so disable when hacks on #1439

leezer3 added a commit that referenced this pull request Oct 2, 2026

Change: Use 0.65 figure for frontal area

c60c258

#1439

leezer3 merged commit d7fe432 into leezer3:master Oct 2, 2026
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adfriz mentioned this pull request Oct 2, 2026

Fixes and stuff part2 #1441

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