[steamer_ctn]

cjakeman, on 24 July 2021 - 10:39 AM, said:

I agree - the default should definitely be 100%.

There has been mention of adding a legacy switch to provide enhanced compatibility with MSTS. This could move the setting from 100% to 130% and back again.

I have been reflecting on this some more.

When I add functionality to the physics engine of OR I try to work to the following principles (guidelines):
i) Performance - the feature should ensure that the train performs "true to life", and add to the realism of the trains performance in OR. Ideally this should be confirmed against an appropriate railway test report.


ii) Consistency - the feature should operate in the same way regardless of which users PC it is run on.


Sadly I believe that the "Adhesion Correction Factor" breaks these two principles.

Firstly if we consider adhesion and its potential impact on trains in OR.

Typically most early generation diesels had adhesion values around 33%, whereas more modern diesels can have values around 45%. The current OR default value is set is 33%. So when we apply the 130% default value we are changing the OR default value to 42.9%.

So by applying a "global modifier" such as this we are potentially impacting the "true to life" performance of all the diesels operating in our scenario, as we are not allowing for individual performance of diesels, and in some instances we are setting the value artificially high.


In regards to the second principle (consistency), consider the following two scenarios, where the content creator is configuring a locomotive with a adhesion value of 42.9%:

Scenario 1 - If they have their PC set to the default value of 130%, and the user has their OR environment set to 100%, then the user may experience slippage whereas the content creator will not.

Scenario 2 - If the content creator uses 100% to develop the locomotive configuration, and the user has theirs set to 130%, then they will experience a different performance to the content creator.

Hence it appears that we both agree that the appropriate way for adhesion to be handled is for this global value to be fixed at 100%, and appropriate Curtius Kniffler adhesion parameters to be included in the individual ENG file.

However, based upon my observations, very few content creators appear to be setting the Curtius Kniffler adhesion parameters, and hence moving forward and setting this value back to what it should be (100%) I suspect that more users will experience wheel slip situations. Thus we need to consider the OR Depreciation Policy and Notification (by depreciation I mean how do we remove a parameter or feature from OR - this is often done in commercial software).

As an example, in this instance might be:
i) Version 1.4 - flag this function for removal (use bold red(?) text on the option menu and describe what is going to happen to it) and leave the current default of 130%. Place "sticky" notices in the key forums advising that change is going to happen. Contact any commercial content creators that we have a relationship with and advise them so that they can update any of their stock creations as appropriate. Set the default value of 100% in the unstable release once version 1.4 has been released.

ii) Version 1.5 - remove the global parameter and set the default correction factor to 100%.
In regard to the other two adhesion global parameters:

Adhesion proportional to rain/snow/fog - this should be set to permanently on in Advanced physics, and off in Simple physics. (Could be done in version 1.4)

Adhesion factor random change - this should only be available to be set when in Activity or Timetable mode. (Could be done in version 1.4)

cjakeman, on 24 July 2021 - 10:39 AM, said:

I am even tempted to remove it altogether and wait to see if any concerns are reported.

I agree with this approach.

[darwins]

Quote

very few content creators appear to be setting the Curtius Kniffler adhesion parameters

Some help needed here. How do we set this parameter?

Do we apply to all traction units steam locomotive, diesel (electric, hydraulic, mechanical) locomotive, electric locomotive, steam railcar, diesel or petrol (electric, hydraulic, mechanical) railcar, electric multiple unit?
Where do we find the real life information needed to correctly set this?
How do we change that information into OR entry?
What if we can not find relevant data? Will OR give a good estimate? Is there a way that we can estimate?

[steamer_ctn]

darwins, on 24 July 2021 - 10:06 PM, said:

Some help needed here. How do we set this parameter?

I am happy to give some thoughts around how I think that adhesion should be set in the next couple of days.

As I suspect that this is going to generate some discussion, can you start a new specific thread so that we don't get this particular thread off topic.

Thanks

[cjakeman]

steamer_ctn, on 24 July 2021 - 03:28 PM, said:

I have been reflecting on this some more.


. . .

Could be done in version 1.4

Thanks for giving the adhesion topic more in depth consideration. Continuing on a dedicated thread is a good move.

I'm not intending to make any changes to Menu > Options which affect our release of v1.4. We are close to having all the infrastructure changes in place and the installer ready, so we will shortly move to bug-fixes only.

Thanks to James' provision of Release Candidates, we can work separately on fixes for an immediate release and new features for development. So we don't have to hold back on new work while a release is being prepared. Any bug-fixes can be easily carried over to the development work.


My intention is to continue reviewing all the items in Menu > Options and then to make some proposals and try to reach a consensus. The proposals might:

- remove some redundant options (e.g. MSTS-bin compatible sound)
- remove some categories (e.g. Experimental)
- re-organise some categories
- provide some super-set options like a slider for low-spec to high-spec PC or a check-box for Legacy Compatibility

I don't wish to ignore suggestions for route|activity|timetable-specific options either.


Taken altogether, this is a large project and the changes will be very visible, so it might be split into stages. We should have tackled it much sooner, but better late than never.

[Weter]

Sorry, Chris, the link to release candidates looks broken.

[steamer_ctn]

cjakeman, on 25 July 2021 - 01:03 AM, said:

I'm not intending to make any changes to Menu > Options which affect our release of v1.4. We are close to having all the infrastructure changes in place and the installer ready, so we will shortly move to bug-fixes only.

So is it worthwhile to start to flag this change in v1.4 (with highlighted text and maybe warning message in the log if adhesion is not set correctly?) as the more notice the better?

[Laci1959]

Hello

Quote

And take in account, that different railroad "schools" use different adhesion calculating methods

My handbook used to train drivers gives an adhesion factor of 270N / kN (it also has a Greek letter but is translated correctly by google) for the M62 (Sergei) locomotive. This type is dependent. In addition, the starting traction is given for some locomotives.
How does this become ORTSCurtius_Kniffler?

Regards Laci 1959

[BillC]

Weter, on 25 July 2021 - 01:56 AM, said:

Sorry, Chris, the link to release candidates looks broken.

Works for me. Perhaps you may need to be a member of the OR development group. Which is a private forum.

[Weter]

Most likely, Bill.

[cjakeman]

cjakeman, on 25 July 2021 - 01:03 AM, said:

My intention is to continue reviewing all the items in Menu > Options and then to make some proposals and try to reach a consensus.

Can we move on in the Simulation tab to look at the resistance options?




These are all calculations which make the simulation more realistic.

Is there any need to turn them off?
Do they have a bad impact on the frame rate?
If so, do they affect every train or just the player train?