Issues with Physics engine v4.0

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Issues with Physics engine v4.0

Postby Cobb » Sun May 18, 2014 12:21 am

Hey guys.
Loving some of the changes the new physics engine has brought, although I've had a few problems:
1) Certain cars (Spirit 300, Silker RBLK, Century R11B been the ones I've experienced it in) have a tendency to go on two wheels around every single corner I take, then it bounces around changing between the two wheels on the left, then on the right, spins out and eventually goes back down on four wheels. The Silker even goes on the two rear wheels on accelerating off the start. Anyway to fix this?
2) When I go to change back to v2.1 so I can drive this cars or test the differences between the engines, it wont let me change out of v4.0. I dont know why. (Note: I had to change into v4.0 when I first opened the game up.)
Any help is Appreciated.
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Re: Issues with Physics engine v4.0

Postby tlow » Sun May 18, 2014 7:00 am

Cobb wrote:Hey guys.
Loving some of the changes the new physics engine has brought, although I've had a few problems:
1) Certain cars (Spirit 300, Silker RBLK, Century R11B been the ones I've experienced it in) have a tendency to go on two wheels around every single corner I take, then it bounces around changing between the two wheels on the left, then on the right, spins out and eventually goes back down on four wheels. The Silker even goes on the two rear wheels on accelerating off the start. Anyway to fix this?


I recall that Simon reported a similar problem with another Supercar (and even made a video of it, which I can't find now). The Spirit 300 physics was last updated here: https://sourceforge.net/p/speed-dreams/code/5725. I'm not sure if that was included in the 2.1 beta, so check the sc-spirit-300.xml file and manually apply those changes to test them. The Silber RBLK and Centuary R11B have not been updated in a long time and should not be affected by the new physics engine (but I'm not an expert in SD physics development).

Cobb wrote:2) When I go to change back to v2.1 so I can drive this cars or test the differences between the engines, it wont let me change out of v4.0. I dont know why.


This sounds like a bug. I'm not able to reproduce it using a build from recent source code checkout, so it may already be fixed. A work around is to edit the config in <localdir>/config/raceengine.xml. Search for "simu". Change "simuv4" to "simuv2.1".

Cobb wrote:(Note: I had to change into v4.0 when I first opened the game up.)


This has been fixed since the 2.1beta was released: https://sourceforge.net/apps/trac/speed ... ticket/838

simuv4 features are controlled in <localdir>/drivers/human/car.xml which should look like this: https://sourceforge.net/p/speed-dreams/ ... an/car.xml. If your file is different, try the new version and see if that helps. If all the simuv4 features are disabled, it is supposed to behave exactly simuv2.1.
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Re: Issues with Physics engine v4.0

Postby Cobb » Sun May 18, 2014 2:13 pm

tlow wrote:I recall that Simon reported a similar problem with another Supercar (and even made a video of it, which I can't find now). The Spirit 300 physics was last updated here: https://sourceforge.net/p/speed-dreams/code/5725. I'm not sure if that was included in the 2.1 beta, so check the sc-spirit-300.xml file and manually apply those changes to test them. The Silber RBLK and Centuary R11B have not been updated in a long time and should not be affected by the new physics engine (but I'm not an expert in SD physics development).

Ill will get on to testing that as soon as I can, as for the Silber and the Centuary, maybe the fact they haven't been changed lead to something funny when the new physics was implemented? Would fiddling with the code fix it maybe, if I learnt what I was doing?
tlow wrote:This sounds like a bug. I'm not able to reproduce it using a build from recent source code checkout, so it may already be fixed. A work around is to edit the config in <localdir>/config/raceengine.xml. Search for "simu". Change "simuv4" to "simuv2.1".

I had a feeling a simple go into the files to change it will be the fix, would it be more benificial to get a recent source build (If the average newbie can get them at all) to fix some of these problems.
Will give feedback on how I go later.
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Re: Issues with Physics engine v4.0

Postby Cobb » Sun May 18, 2014 3:01 pm

I did some testing,
The Spirit 300 fix did the trick, it was very twitchy still (but i find that with a lot of cars) but doing the car.xml fixed made the Spirit's twitchiness a little more controllable and drivable with my xbox gamepad.
the car.xml also solved the silber somewhat. It seems to be a bit of an enigma, on goldstone-sand its starts in the air but doesnt get weightless however driving on strret 1 (which was where I originally noticed the problem.) it stays on the ground until rounding a tight corner, the tight corners are the problem with the silber.
Im a little confused as to why my car.xml file was different to the one you put up. For reference this was the one I had:
Code: Select all
<?xml version="1.0" encoding="UTF-8"?>
<!--
    file        : car.xml
    created     : Sun Aug 17 22:09:03 CEST 2003
    copyright   : (C) 2003 by Eric Espié                         
    email       : Eric.Espie@torcs.org   
    version     : $Id: car.xml 5646 2013-08-01 21:50:10Z kakukri $                                 
-->

<!--    This program is free software; you can redistribute it and/or modify  -->
<!--    it under the terms of the GNU General Public License as published by  -->
<!--    the Free Software Foundation; either version 2 of the License, or     -->
<!--    (at your option) any later version.                                   -->

<!DOCTYPE params SYSTEM "../../../../src/libs/tgf/params.dtd">

<params name="default car" version="1.2">

<!-- Enabling new simuv4 features -->
   <section name="Features">
      <attstr name="shifting aero coordinates" in="yes,no" val="yes"/>
      <attstr name="fixed low speed grip" in="yes,no" val="yes"/>
      <attstr name="realistic gear change" in="yes,no" val="no"/>
      <attstr name="realistic rev limiter" in="yes,no" val="yes"/>
      <attstr name="tire temperature and degradation" in="yes,no" val="no"/>
      <attstr name="fixed wheel force" in="yes,no" val="yes"/>
   </section>

</params>
Cobb
 
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Re: Issues with Physics engine v4.0

Postby tlow » Mon May 19, 2014 3:04 am

Cobb wrote:I did some testing,
The Spirit 300 fix did the trick, it was very twitchy still (but i find that with a lot of cars)


The physics for some SC cars are changed for 2.1 which gave them a lot more more oversteer. I don't like the updated SC cars, to be honest.

Cobb wrote:but doing the car.xml fixed made the Spirit's twitchiness a little more controllable and drivable with my xbox gamepad.


Tuning the sensitivity settings may help, but I can't help you with that, since I only use wheel and pedals which are much less fiddly.

Cobb wrote:the car.xml also solved the silber somewhat. It seems to be a bit of an enigma, on goldstone-sand its starts in the air but doesnt get weightless however driving on strret 1 (which was where I originally noticed the problem.) it stays on the ground until rounding a tight corner, the tight corners are the problem with the silber.


I was wrong about the Silber and Centuary not being updated: https://sourceforge.net/p/speed-dreams/code/5728.

And I found Simon's report about toppling cars: https://sourceforge.net/apps/trac/speed ... ticket/841.

Cobb wrote:Im a little confused as to why my car.xml file was different to the one you put up.


You are using the 2.1beta release. Several things have been fixed since then. I don't know why there hasn't been a 2.1beta2 yet. SD's release process is not very transparent.
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Re: Issues with Physics engine v4.0

Postby Cobb » Mon May 19, 2014 10:09 am

Thanks heaps Tlow.
Since posting I've fiddled with my sensitivity. Seems I had been going in the wrong direction. I had reduced the sensitivity so much that it had no real force input, it was nothing or everything which mean I usually spun in an instant (usually trying to stay in straight line lol), upped the sensitivity a little and now little inputs actually work.
After reading the bug ticket. If I encounter any other tipping cars would it be wise to edit the suspensions in xml, and as it seems that the 2.1.0 beta is so far behind is it worth reporting them here?
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Re: Issues with Physics engine v4.0

Postby tlow » Mon May 19, 2014 4:45 pm

It's always worth reporting problems, either here, or on the bug tracker if you have a sourceforge account. Based on the problems you encountered, it's obvious that a second beta is long overdue. Perhaps this will nudge the devs into make a new release.
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