Physics issue: Bump sound

[Devriv]

Hello everyone, :matte-motes-big-grin:

I’m working on some pathways and all the pieces work as expected, except a circular one. When I connect any other piece to it, walking onto the surface of the circle produces the pump sound.  This would suggest that the surfaces are uneven, but all the pieces are of the same height.  In fact, I get the bump sound even when I connect the same circle to its own copy(shown below)!  No such problem when the circle is set to convex hull but I need all the pieces to have prim physics.  I’ve used triangle (no analyze) physics for all the pieces. 

I made a lower poly test mesh and have left it in the sandbox below.  I used the high LOD for physics to rule out issues with my physics model.  I still get the bump sound.



I’m not positive what the solution is.  Your suggestions would be appreciated :matte-motes-nerdy:

http://www.pasteall.org/blend/42945

secondlife://Aditi/secondlife/Mesh%20Sandbox%203/27/11/23

Thank you in advance

 

[arton Rotaru]

Remove the highlighted faces and export that as a physics mesh, and select this one as the physics shape during upload. And keep it as a triangle based physics mesh as you did before.



I have left an example at the same location as yours.

[Devriv]

Thank you so much Arton, that made the bump go away :catvery-happy::matte-motes-big-grin:

I use triangle physics often, it's very efficient and low LI, but at times it can behave in ways which I'm at a loss to explain...such as this instance

And thank you very much Drongle for your help inworld

[Zed Tremont]

Hi Devriv,

A bit late since it's already solved but perhaps a tip that might help in future.

You can make a physics shape visible with Firestorm viewer (perhaps in other viewers too)

activate your advance menu in preferences -> choose the last option in this menu to activate the develeper menu.

Developer -> render metadata -> "check" physics shapes

to undo this just uncheck it again.

You will see mesh physics shapes in blue, orange or red

blue: simple physics shape which is good

Orange: too complex, physics shapes can create lag since the calculations of collission boxes are complex. Physics shapes do not like dense clusters of verts. In case of orange you might find out that when you decrease the size of the mesh the Li increase because of this density.

Red: downright bad and best to restart, test have showed that these can "consume" the CPU of the server pretty bad. 

[Devriv]

Thank you very much Zed, that’s good to know. The official viewer, the viewer I’ve always used, also allows one to make the physics visible (in blue) but I don’t think it has the other options; I’ll look into it.  I actually used it for the circle in question but saw no anomalies. 

In passing, one aspect of FS that I’m not at all enthusiastic about is its default LOD factor of 4 (or so I was informed some time ago). Yes it can be adjusted and lowered, but it should not have been made the default. One can only hope that those using it, especially builders, are mindful of the fact. 

[ChinRey]

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Devriv wrote:

Thank you very much Zed, that’s good to know. The official viewer, the viewer I’ve always used, also allows one to make the physics visible (in blue) but I don’t think it has the other options; I’ll look into it.

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It has. The show phsyics shape code is shared by and identical in all current viewers.

 

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Devriv wrote:

I actually used it for the circle in question but saw no anomalies. 

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You wouldn't because the anomaly is so tiny. The simple explanation is that there are no such things as exact measurements and alignment in Second Life, so the server and viewer will always see a tiny height diffrence between the two road surfaces even if there is none. Arton's solution is probably the best one: simply remove the physical surfaces the software believes you are bumping into.

Three less good solutions are to use analyzed physics, convex hulls or a script removing the bump sound. All of these methods have serious drawbacks but they may do in an emergency.

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Devriv wrote:

In passing, one aspect of FS that I’m not at all enthusiastic about is its default LOD factor of 4 (or so I was informed some time ago).

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It's not that bad but yes, it's too high (1.5 and 2 at mid and high graphics respectively). I actually believe that RenderVolumeLODFactor fucntion is one of LL's biggest msitakes ever. It adds a tremendous lot of lag and its only purpose is to compensate for mistakes made by incompetent builders...

[Devriv]

Thank you for the reply Rey :catvery-happy:   So the show physics feature of the two viewers are identical?  I’ve not come across any physics shapes in the official SLViewer that have appeared in any colour other than blue, so far.  Henceforth I’ll be mindful of the orange and red shapes

Firestorm’s LOD is not set to 4?  Sorry FS, I was misinformed.  As Ralph Kramden would say, “I’ve got a Big mouth!”

They are most definitely not incompetent Rey; some have professional-level knowledge of modeling, texturing, and 3D software and are experts. Even the option of letting the uploader make the LODs is bypassed and the LODs (even Medium ones!) zeroed because they want low LI. This is deliberate choice, not a question of competence.  On the other hand some may find making the lower LODs time consuming, which certainly can be, but the more experience one gains the faster that process becomes. 

Anyway, please understand that I’m speaking as an amateur and based on personal experience and observation as a regular SL resident.  :matte-motes-big-grin:

[ChinRey]

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Devriv wrote:

They are most definitely not incompetent Rey; some have professional-level knowledge of modeling, texturing, and 3D software and are experts. Even the option of letting the uploader make the LODs is bypassed and the LODs (even Medium ones!) zeroed because they want low LI.

This is deliberate choice

, not a question of competence.

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Yes it is a deliberate choice but it's done because of incompetence. Competent mesh makers have a vast range of more effective and less destructive techniques to reduce LI. LOD butchery is for the fakers. not the makers.