Strange acceleration data in train.dat file - what happens internally?

by Ghost of Kymlinge Sun Mar 08, 2020 3:25 pm

I'm looking into the train.dat file, the acceleration section, for a tram I have not created myself. The numbers are somewhat strange, and causes error messages on loading. Nethertheless, the tram is drivable in OpenBVE.

I'm curious to know how this data is treated internally when a1 is always zero and v2 < v1? Are some of the less reasonable numbers replaced by other default values, or is the simulation in this case actually calculating the tram's behaviour from what is in the train.dat file?

This is a table of the values:

	P1	P2	P3	P4	P5	P6
a0	4	4	4	4	4	4
a1	0	0	0	0	0	0
v1	80	80	80	80	80	80
v2	10	20	30	40	50	60
e	1	1	1	1	1	1

by Phonteus Nevolius Mon Mar 09, 2020 6:58 am

It might come from the BVE2 times when tutorials and localised specifications were scarce and developers just didn't have enough information.

by **leezer3** Mon Mar 09, 2020 8:39 pm

Looking in the parser, the following happens:

As a0 is zero, a constant 1.0 is used:
https://github.com/leezer3/OpenBVE/blob/master/source/OpenBVE/Parsers/Train/TrainDatParser.cs#L927

As v2 is less than v1, it is replaced by v1:
https://github.com/leezer3/OpenBVE/blob/master/source/OpenBVE/Parsers/Train/TrainDatParser.cs#L212

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Strange acceleration data in train.dat file - what happens internally?

Strange acceleration data in train.dat file - what happens internally?

Re: Strange acceleration data in train.dat file - what happens internally?

Re: Strange acceleration data in train.dat file - what happens internally?

Re: Strange acceleration data in train.dat file - what happens internally?

	P1	P2	P3	P4	P5	P6
a0	4	4	4	4	4	4
a1	0	0	0	0	0	0
v1	80	80	80	80	80	80
v2	10	20	30	40	50	60
e	1	1	1	1	1	1

	P1	P2	P3	P4	P5	P6
a0	4	4	4	4	4	4
a1	0	0	0	0	0	0
v1	80	80	80	80	80	80
v2	10	20	30	40	50	60
e	1	1	1	1	1	1

	P1	P2	P3	P4	P5	P6
a0	4	4	4	4	4	4
a1	0	0	0	0	0	0
v1	80	80	80	80	80	80
v2	10	20	30	40	50	60
e	1	1	1	1	1	1