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Issue Details (XML | Word | Printable)

Key: SVC-956
Type: New Feature New Feature
Status: Open Open
Priority: Normal Normal
Assignee: Unassigned
Reporter: Jacek Antonelli
Votes: 19
Watchers: 6
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2. Second Life Service - SVC

Allow "hollow" sculpties with reduced mass

Created: 16/Nov/07 10:59 PM   Updated: 14/Mar/08 08:57 PM
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Component/s: Physics, Simulation
Affects Version/s: None
Fix Version/s: None

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 Description  « Hide
It would be very useful to creators of sculpty vehicles and other physical objects, if sculpted prims could have their "hollow" attribute adjusted for the purpose of reducing the prim's mass. Sculpted prims are the only prim type whose mass cannot be adjusted without changing its size, which limits its usefulness in creating vehicles.

For example, consider a sculpted prim canoe. Although it looks like a thin shell that's empty inside, to the physics engine it is a large solid sphere, and so it has far more mass than it should to feel remotely realistic.

I'm not asking for hollow sculpties to be rendered differently than non-hollow sculpties, just that they have the same mass as a sphere of the same size and hollowness.



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Coyote Pace added a comment - 17/Nov/07 10:13 AM
How hard would it be for the client (or the server, I dunno) make a rough-and-ready calculation of the mass ratio of any given sculpty when it's stored? Then store that adjustment factor with the prim itself, as you say, in the hollow field or wherever convenient. That would be a one-time hit, and the physics engine would have the number ready to go when needed.

But barring all that filigree, a manually-adjusted field would be better than nothing, certainly.

Unless there's some previously unexamined downside? I note that the Lindens have had to tinker with the degenerate surface detection and handling because such scultpies were being exploited for some kind of griefing purposes. Who would'a thought?


LaeMi Qian added a comment - 20/Nov/07 12:38 PM
I like Coyote's solution very much

Jacek Antonelli added a comment - 20/Nov/07 12:47 PM
Automatically calculating an appropriate hollowness would be convenient (also quite hard to program). But right now, it's not even possible to apply such a hollowness to a prim, even if it could calculate it. I'd say once we cross the current bridge, we can think about the next one.

Patchouli Woollahra added a comment - 23/Nov/07 12:29 PM
The point of the server defaulting to calculating sculpties as spheroids is to avoid having to cope with physics for them on a per-polygon basis, especially when said sculpties result in geometry innately unsafe for simulations.

This Hollowing option for sculpties would be a good middle ground, although one would have to consider exactly how to temporarily represent hollowing while creators adjust their sculpties for flotation.

Re: Coyote's comment - I fail to see how sculpties would cause any more issues with physics than their equivalent spheroids, excepting the absence of hollowing for flotation physics.


Rob Linden made changes - 22/Dec/07 01:13 AM
Field Original Value New Value
Workflow jira [ 16872 ] jira-2007-12-21 [ 21276 ]
Rob Linden made changes - 22/Dec/07 01:47 AM
Workflow jira [ 21276 ] jira-2007-12-21 [ 23189 ]
Rob Linden made changes - 23/Dec/07 12:19 AM
Workflow jira-2007-12-21 [ 23189 ] jira-2007-12-22a [ 48558 ]
IAm Zabelin added a comment - 14/Mar/08 08:54 PM
Yes, this would be a great feature - i expect auto-calculation would be tricky and cause delay - so even a % field for creator to thumbsuck or calc as he pleases would be good.

That said, I'm going to suggest that this and VWR-4418 can work hand-in-hand.

VWR-4418 requests a method of using a std existing tortured prim to define an estimated collision map for sculpts (and seperate the sculpt on a new tab etc). Using that same logic, the tortured prim used to define the collision map could be used to calculate the mass.


IAm Zabelin added a comment - 14/Mar/08 08:57 PM
I'm going to suggest that SVC-956 and VWR-4418 can work hand-in-hand.

SVC-956 requests a method to more accurately determine a sculpts mass.

VWR-4418 requests a method of using a std existing tortured prim to define an estimated collision map for sculpts (and separate the sculpt on a new tab etc).

Using that same logic, the tortured prim used to define the collision map could be used to calculate the mass.


IAm Zabelin made changes - 14/Mar/08 08:57 PM
Link This issue Relates to VWR-4418 [ VWR-4418 ]
Sue Linden made changes - 13/Nov/08 12:03 PM
Workflow jira-2007-12-22a [ 48558 ] jira-2008-11-14 [ 80454 ]
Sue Linden made changes - 13/Nov/08 04:27 PM
Workflow jira-2008-11-14 [ 80454 ] jira-2008-11-14a [ 86356 ]
Sue Linden made changes - 13/Nov/08 04:42 PM
Workflow jira-2008-11-14 [ 86356 ] jira-2008-11-14a [ 90917 ]
Sue Linden made changes - 13/Nov/08 04:52 PM
Workflow jira-2008-11-14 [ 90917 ] jira-2008-11-14a [ 94092 ]