<div dir="ltr">The key point being missed here is that OpenSim code is not 'frozen' or 'static' in any way. The llCastRay function is not exceptional in this respect; it could readily be extended (by someone knowledgeable in the subject area) to support the behavior that is anticipated based on the implementation in SL.<div>
<br></div><div>Whether or not anyone participating in this discussion meets that description, it is quite likely that this will eventually happen; all that's required is a bit of patience and/or coding skill (depending on who you might be ;)<div>
<br></div><div>Not to put too fine a point on it, but "...patches are welcome." For the rest of us, that translates as "Be patient."</div></div><div><br></div><div><br></div><div>Cheers!</div><div>James</div>
</div><div class="gmail_extra"><br><br><div class="gmail_quote">On Tue, Feb 25, 2014 at 10:20 PM, Dahlia Trimble <span dir="ltr"><<a href="mailto:dahliatrimble@gmail.com" target="_blank">dahliatrimble@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">OpenSimulator currently only uses bounding boxes for llCastRay(), regardless of the physics engine selected. Other collisions are computed in the physics engine, and in the case of BulletSIm or ODE, are computed against mesh triangles or convex hulls, and are usually quite accurate.<br>
</div><div class="HOEnZb"><div class="h5"><div class="gmail_extra"><br><br><div class="gmail_quote">On Tue, Feb 25, 2014 at 7:46 PM, Dr Ramesh Ramloll <span dir="ltr"><<a href="mailto:r.ramloll@gmail.com" target="_blank">r.ramloll@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Hello, are we to assume that opensim will only use bounding boxes for llCastRay or when detecting collisions? There are a lot of compelling applications that require the data for the point at which the ray hits the surface of a mesh object or for the point of collision on a mesh object. Is this one area where Second Life is definitely ahead because of Havok4? I am not very familiar with the underlying opensim infrastructure, so would be glad to hear more about this.<div>
Thanks</div><div>R</div></div><div class="gmail_extra"><div><div><br><br><div class="gmail_quote">On Tue, Feb 25, 2014 at 12:00 PM, Chris <span dir="ltr"><<a href="mailto:mewtwo0641@gmail.com" target="_blank">mewtwo0641@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">If I recall correctly, the default physics engine was switched to BulletSim some time ago although I can't recall when. Assuming recent code is being used and also assuming the physics engine hadn't been switched from default I would venture to say that BulletSim is likely being used, but, that is just a guess on my part based on what I've seen and experimented with myself; I have no idea what setup OSGrid is using since it has been a while since I've ran a sim connected there.<br>
<br>
I haven't had a chance to test this myself on BulletSim but I have noticed some slight quirkiness with cast ray on some surfaces (especially angled prims). I've not given it a full run on tests as I haven't used the cast ray functions all that much in my scripting.<div>
<div><br>
<br>
On 2/25/2014 10:48 AM, Handy Low wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Gwyneth Llewelyn <gwyneth.llewelyn <at> <a href="http://gwynethllewelyn.net" target="_blank">gwynethllewelyn.net</a>> writes:<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Hi Handy,<br>
<br>
Just for the sake of completeness, did you test with ODE or BulletSim? I<br>
</blockquote>
believe the implementation might be<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
slightly different (or, then again, it's just my not-so-precise testing).<br>
<br>
Thanks,<br>
<br>
- Gwyn<br>
<br>
On 25/02/2014, at 16:09, Handy Low wrote:<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Currently it seems that the OpenSim implementation of llCastRay() gives<br>
coordinates on a target object that lie on the bounding box of the<br>
</blockquote></blockquote>
object<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
rather than on the face of the prim itself.<br>
<br>
For example, casting a ray at a pair of linked cubes in OpenSim will<br>
</blockquote></blockquote>
generate<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
coordinates that lie on the cuboid bounding box that constrains both<br>
</blockquote></blockquote>
cubes.<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Likewise, casting a ray at a sphere will generate a point on the<br>
</blockquote></blockquote>
sphere's<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
cubic bounding box.<br>
<br>
In SL, the same tests will both return points on the prim surfaces.<br>
<br>
Is this expected behaviour?<br>
<br>
Thanks<br>
</blockquote></blockquote>
Thanks to Michael and Gwen for the fast replies.<br>
<br>
Off the top of my head, I don't know which physics engine they were using,<br>
or how I can find out - the tests I've been doing have been in OSGrid<br>
(Sandbox Plaza) and in Kitely, if that's any help.<br>
<br>
--<br>
Handy<br>
<br>
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