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CoffeeDujour

Please. Can we have more physics.

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The other problem you seem to be forgetting is that physics collisions take a lot of processing. This is why even on the server we need simple and reliable, volume representations, not the flat triangles that many creators default to. If we can't rez reliably because the server side physics has been skimped on by a creator then we have zero hope of getting it to work on the client side.

On 5/2/2018 at 4:07 AM, CoffeeDujour said:

Even CAMERA ONLY client side collision would be awesome. It wont affect anyone else and there will be no more clipping into walls for a split second while the viewer waits for the region to tell it to move.

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That would be good if visible mesh was not stupidly complex. But wait we can rely on low LOD models, oh no, we forgot the creator has zapped the LOW LOD to keep the LI low and let them cram even more pointless vertices into an over-complex high lod model.

To determine collisions you need to have a basic collision mesh. In Havok, for example, the engine loves spheres, why? because to collision detect a sphere you need only know the centre and the radius, anything closer than that must be hitting it. Extend that to triangles. Every triangle needs to be checked for intersection with every other triangle a far more complex task especially when there are millions of the little fellas in the scene. There are lots of tricks you can do by subdividing the scene to rule out things that can't possibly intersect. Except even then we have every trick under the sun employed to force the viewer to misidentify objects that are out of view and cullable so I have severe doubt we could ever rely on visual meshes and cunning logic to help us here. This is why we beg and plead with creators to give a proper physics shape that is low poly and volume representative of the visible mesh. 

Now, this is not to say that you could not create some rules, let's say "use the bounding box" as a starter, except that people have been gaming the bounding box size to force LOD. You could compute a convex hull for objects, but you'd need to be able to work out what the "true" shape of a mesh is and again I suspect that you'd end up generating vast numbers of false collisions.

I fully agree with the premise that @CoffeeDujour raises. It would be awesome not to ghost through tables just cos your AO is a little antsy but unless there is a reliable way to take any arbitrary item in SL and determine a reliable collision shape, it's not going to be viable. no matter what physics engine you use.

All that being said. Perhaps I am expecting too much here. Perhaps you could leave the physics problem to the user, if the creator made bad physics shapes and you want to use it in client-side collisions then tough, buy better content. If we put the onus on the user/sim owner who wanted the physics to work to only use sensible objects, the current physics decomp calls that a Havok enabled viewer has access to could be used, this would also go somewhay to encouraging more creators to pay attention ot LOD models and physics; on the downside though, at the present time that moves the argument back to Whirly's point. Only Havok enabled viewers could possibly work then. 

On which note:

On 9/21/2018 at 6:49 AM, animats said:

Which is why the Firestorm viewer doesn't even try to show that.

It absolutely does. You must be using your own self-compile or the OS version cos the Havok build will replicate the LL viewer.

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Perhaps he tried the firestorm physics upload before they got the 64bit havok stuff somewhat recently?  I recall it wasn't there last year when I tried too, but it is now for sure :)

I agree about the physics shape, often I disable physics on various mesh. Its great for decorations and such, so I can see why some creators might skimp on physics, knowing people will likely do just that, set to phantom and disable the physics, add it to a linkset which gets its own simpler invisible prim/mesh physics shape.  Of course thats not always a viable solution.  Its enlightening to turn on the physics Render data in the viewer, you can see exactly what Beq is getting at, theres a HUGE array of things all over the place, with varying levels of quality and attention to physics or any other such quality concerns, sometimes the physics is just jacked, and I imagine the more of that the more lag in an area created too.

 

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