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+--- Thread: Help simulation in world and local space (/thread-2855.html)
simulation in world and local space - user23 - 09-04-2021
Hello! ObiSolver can perform the simulation in one of two spaces: [b]world space[/b] (the default) and [b]local space[/b].
http://obi.virtualmethodstudio.com/tutorials_4/localspace.html
But I can't find this in the last version of Obi Cloth.
Where can I find this mode?
RE: simulation in world and local space - josemendez - 09-04-2021
That manual is for legacy (now unsupported) versions: 4.X and older. Current version is 6.0.1.
Since version 5.0, simulation is always performed in the solver's local space. This results in better performance and makes it easier to reason about what space you're working in. It also avoids floating point precision problems when working away from the world's origin, which is a must for large game worlds. Quoting the manual:
http://obi.virtualmethodstudio.com/tutorials/obisolver.html
Quote:Solvers always perform the simulation in local space. This means that translating, rotating or scaling the solver will rigidly transform the simulation as a whole.
To emulate world space, just leave the solver at the world's origin. This way, local and world space become the same. Note you can also inject world-space inertial forces into the solver, using the solver's world linear/angular inertia scale parameters.
RE: simulation in world and local space - user23 - 12-04-2021
(09-04-2021, 09:38 AM)josemendez Wrote: That manual is for legacy (now unsupported) versions: 4.X and older. Current version is 6.0.1.Thanks for your answer! Can I use simulation in local space for scaling my cloth in runtime?
Since version 5.0, simulation is always performed in the solver's local space. This results in better performance and makes it easier to reason about what space you're working in. It also avoids floating point precision problems when working away from the world's origin, which is a must for large game worlds. Quoting the manual:
http://obi.virtualmethodstudio.com/tutorials/obisolver.html
To emulate world space, just leave the solver at the world's origin. This way, local and world space become the same. Note you can also inject world-space inertial forces into the solver, using the solver's world linear/angular inertia scale parameters.
RE: simulation in world and local space - josemendez - 12-04-2021
(12-04-2021, 01:23 PM)user23 Wrote: Thanks for your answer! Can I use simulation in local space for scaling my cloth in runtime?
More or less. Scaling the solver will scale the entire simulation space, not just your cloth.
This means that the "world" your cloth is being simulated in is smaller/larger so the cloth will be smaller/larger as well. For many uses this is close enough.
RE: simulation in world and local space - user23 - 13-04-2021
(12-04-2021, 01:33 PM)josemendez Wrote: More or less. Scaling the solver will scale the entire simulation space, not just your cloth.Do you mean that "scaling solver" is scaling the main object in hierarchy which has component Obi solver? I can show small video how I try to scale this object:
This means that the "world" your cloth is being simulated in is smaller/larger so the cloth will be smaller/larger as well. For many uses this is close enough.