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| ID | Project | Category | View Status | Date Submitted | Last Update | |||||
| 0008141 | opensim | [REGION] Script Functions | public | 2017-04-04 05:30 | 2017-06-26 03:01 | |||||
| Reporter | UbitUmarov | |||||||||
| Assigned To | UbitUmarov | |||||||||
| Priority | none | Severity | feature | Reproducibility | N/A | |||||
| Status | assigned | Resolution | open | |||||||
| Platform | Operating System | Operating System Version | ||||||||
| Product Version | master (dev code) | |||||||||
| Target Version | master (dev code) | Fixed in Version | ||||||||
| Summary | 0008141: experimental Inertia override | |||||||||
| Description | so far mass, center of mass and moment of inertia of a link set are calculated automatically from the prims density, volume, shape and relative positions. In most cases only prims known to physics are consider. So every time you change prims, the dynamic characteristics of the link set change. Additionally the automatic calculations may not be that good in same cases. added a new set of functions to replace those automatic values by ones provided on script. the values are stored on the root prim osSetInertia(float mass, vector centerOfMass, vector principalInertiaScaled, rotation lslrot) arguments: - Mass total mass of link set - centerOfMass location of center of mass relative to root prim in local frame - principalInertiaScaled moment of inertia relative to principal axis and center of mass,Ixx, Iyy, Izz divided by mass so they can be changed independently - lslrot rotation of the inertia, relative to local axis to avoid think about moment of inertia relative to a body principal axis, we can tell they can be like the ones of a box, sphere or cylinder osSetInertiaAsBox(float mass, vector boxSize, vector centerOfMass, rotation lslrot) osSetInertiaAsCylinder(float mass, float radius, float lenght, vector centerOfMass, rotation lslrot) osSetInertiaAsSphere(float mass, float radius, vector centerOfMass) to return to normal calculation: osClearInertia() for debug: list osGetInertiaData() returns a list with contents: - float the total mass of the link set - vector center mass position relative to root prim - vector elements of diagonal of inertia Ixx,Iyy,Izz divided by total mass - vector elements of upper triangle of inertia Ixy (= Iyx), Ixz (= Izx), Iyz(= Izy) divided by total mass only supported by ubOde for now unrealistic values can be used, but should be avoid. Restrictions may be added In future. Some may make the physics engine very unhappy if the relative scale of Ijj, or box dimensions is large, physics simulation math errors will also large. the Inertia values and box, cylinder or sphere dimensions can't not be zero | |||||||||
| Tags | No tags attached. | |||||||||
| Git Revision or version number | ||||||||||
| Run Mode | Standalone (1 Region) | |||||||||
| Physics Engine | ubODE | |||||||||
| Script Engine | ||||||||||
| Environment | Unknown | |||||||||
| Mono Version | None | |||||||||
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(0031753) UbitUmarov (administrator) 2017-04-14 17:36 |
keep in mind that simulation units are still not SI. Water as a density of 1000Kg/m3 but in simulation that is 10MassUnits/m3 so provide a mass you would consider from RL divided by 100. ie for a 2000kg car use 20. |
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(0032076) djphil (reporter) 2017-06-26 03:01 edited on: 2017-06-26 03:02 |
Please, keep in mind. If new functions are added to opensim but are not added to the opensim wiki, then many users ignore their existence and how they work. In this case, creating new function loses much of its interest ... Call for Volunteers osClearInertia @ http://opensimulator.org/wiki/OsClearInertia [^] osGetInertiaData@ http://opensimulator.org/wiki/OsGetInertiaData [^] osSetInertia @ http://opensimulator.org/wiki/OsSetInertia [^] osSetInertiaAsBox @ http://opensimulator.org/wiki/OsSetInertiaAsBox [^] osSetInertiaAsCylinder @ http://opensimulator.org/wiki/OsSetInertiaAsCylinder [^] osSetInertiaAsSphere @ http://opensimulator.org/wiki/OsSetInertiaAsSphere [^] Tank you in advance. |
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Issue History |
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| Date Modified | Username | Field | Change |
| 2017-04-04 05:30 | UbitUmarov | New Issue | |
| 2017-04-04 05:30 | UbitUmarov | Status | new => assigned |
| 2017-04-04 05:30 | UbitUmarov | Assigned To | => UbitUmarov |
| 2017-04-14 17:36 | UbitUmarov | Note Added: 0031753 | |
| 2017-06-26 03:01 | djphil | Note Added: 0032076 | |
| 2017-06-26 03:02 | djphil | Note Edited: 0032076 | View Revisions |
| 2017-06-26 03:02 | djphil | Note Edited: 0032076 | View Revisions |
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Issue History |
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