Thursday, September 29, 2011

2013 HELP: Sim crossing, problems and solutions

Sim crossing, problems and solutions
Sim Crossing
Sim crossings are a big problem, especially to people using scripted vehicles.  I am starting a post series on solutions that people propose or are using to moderate the problem.

Moderate the speed
I got this proposed solution directly from qie.niangao of the Virtual Railway Consortium.  It was written by  Lynn Kukulcan, who credits Carlyle Theas, with the idea and Eris Delacroix with help in debugging.*
The expression below calculates a maximum speed for any position on a sim.  It can be used in a script to make sure that a vehicle slows down at sim boundaries and especially at corners.  The speed is determined by the Gaussian function.   (Click the link to see the dome-shaped curve.)
This function looks like a reasonable choice for speed moderation at boundaries.  I don't know that it is the best.  That would depend on how well it adjusts the speed and on its computational efficiency.  Perhaps others will  answer those implied questions in comments to this blog post.
float  MaxSpeed =
llPow ( 2.718281828, ( 0 -( 0.00015 * ( Position.x - 128 ) * ( Position.x - 128 ) +  0.00015 * ( Position.y - 128 ) * ( Position.y - 128 ) ) ) ) * 12 + 0.5;
 *Creative Collaboration.     One of the reasons why people are not flocking to the other grids:
In Second Life we get by with a little help from our friends.  And BTW, it was qie.niangao who suggested this blog series.

Other suggestions? 
There must be other ideas on what we can do to make boundary crossing more satisfactory.  We can try to minimize the transfer load, for example.  In theory, that should reduce problems.  But I have no idea how much improvement we might get.  Perhaps others have experience and could comment.  

If I get enough suggestions, I will organize them into a summary post.

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  1. Well, the lack of highways and railways on other grids doesn't help with that, either, even though region boundaries are considerably less of a problem.

  2. When i have my map open I crash a lot at sim boundaries, but when the map is closed or minimized, I crash a lot less