[ODE] Re: problem with dBodyAddRelForce. help, I'm desperate

Troy Chard troy.chard at shaw.ca
Wed Jul 30 17:50:02 2003


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Hi asko,

Thanks for the reply.  This would seem to verify that something is wonked 
with friction
somewhere if we both getting same problem.
Or we both doing something wrong in our code but i doubt it.  You deduced 
friction by
setting it to 0.  I deduced friction by floating box off ground and testing 
in zero g.

I'm thinking this is a little of the beaten track for ode usage.  For now I 
think I'm going
to go with a different approach involving angular motors.  Alternatively I 
suppose I could
set friction to 0 and use a dampener on the forces involved.

Thanks again for reply.

Troy



At 08:41 PM 7/28/03 +0300, you wrote:
>Hey,
>
>I saw your post in the mailing list archive and I'm amazed by the fact 
>that I ran in to this exact same problem about the same time you sent the mail.
>
>I'm making a raycast car and this thing seems like the only problem left 
>to solve. I'm using the raycasts for creating contact joints and for 
>steering/driving im directly adding forces to the chassis.
>
>Seems that when the chassis is heading at some other angle than n*45 and a 
>force is added to the Z-axis, the chassis will not actually move along 
>it's relative Z-axis, instead (pretty much) along the closest n*45 
>direction. I also tried directly changing the linear velocity, but seems 
>that the situation is exactly same that way.
>
>After playing around with the contact parameters, I came to the conclusion 
>that the problem is actually somewhere in the friction model. None of 
>these problems appear when friction is set to 0.
>
>However that isn't much of a solution, at least not for me. So I'm all 
>ears for suggestions.

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<html>
Hi asko,<br>
<br>
Thanks for the reply.&nbsp; This would seem to verify that something is
wonked with friction <br>
somewhere if we both getting same problem.<br>
Or we both doing something wrong in our code but i doubt it.&nbsp; You
deduced friction by <br>
setting it to 0.&nbsp; I deduced friction by floating box off ground and
testing in zero g.<br>
<br>
I'm thinking this is a little of the beaten track for ode usage.&nbsp;
For now I think I'm going<br>
to go with a different approach involving angular motors.&nbsp;
Alternatively I suppose I could <br>
set friction to 0 and use a dampener on the forces involved.<br>
<br>
Thanks again for reply.<br>
<br>
Troy<br>
<br>
<br>
<br>
At 08:41 PM 7/28/03 +0300, you wrote:<br>
<blockquote type=cite cite><font face="arial" size=2>Hey,</font><br>
&nbsp;<br>
<font face="arial" size=2>I saw your post in the mailing list archive and
I'm amazed by the fact that I ran in to this exact same problem about the
same time you sent the mail.</font><br>
&nbsp;<br>
<font face="arial" size=2>I'm making a raycast car and this thing seems
like the only problem left to solve. I'm using the raycasts for creating
contact joints and for steering/driving im directly adding forces to the
chassis.</font><br>
&nbsp;<br>
<font face="arial" size=2>Seems that when the chassis is heading at some
other angle than n*45 and a force is added to the Z-axis, the chassis
will not actually move along it's relative Z-axis, instead (pretty much)
along the closest n*45 direction. I also tried directly changing the
linear velocity, but seems that the situation is exactly same that
way.</font><br>
&nbsp;<br>
<font face="arial" size=2>After playing around with the contact
parameters, I came to the conclusion that the problem is actually
somewhere in the friction model. None of these problems appear when
friction is set to 0.</font><br>
&nbsp;<br>
<font face="arial" size=2>However that isn't much of a solution, at least
not for me. So I'm all ears for suggestions.</font></blockquote></html>

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