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gh_flex library

Description

gh_flex is the module that manages NVIDIA FleX engine. Flex is a GPU-based particle simulation library designed for real-time applications. It provides a unified interface that is capable of simulating fluids, clothing, solids, ropes, and more. The FleX module requires a CUDA-capable GPU and is currently available on Windows only (the FleX plugin is also available on Linux but the plugin is not stable and then is not shipped yet with GeeXLab).


Number of functions: 47

  1. gh_flex.get_compute_device_name ()
  2. gh_flex.get_version ()
  3. gh_flex.make_phase ()
  4. gh_flex.particles_copy_position_to_vb_fast ()
  5. gh_flex.particles_copy_to_vb ()
  6. gh_flex.particles_create ()
  7. gh_flex.particles_get_phase ()
  8. gh_flex.particles_get_position ()
  9. gh_flex.particles_get_velocity ()
  10. gh_flex.particles_kill ()
  11. gh_flex.particles_map_active_indices ()
  12. gh_flex.particles_map_phase ()
  13. gh_flex.particles_map_position ()
  14. gh_flex.particles_map_velocity ()
  15. gh_flex.particles_set_active_index ()
  16. gh_flex.particles_set_num_active_indices ()
  17. gh_flex.particles_set_phase ()
  18. gh_flex.particles_set_position ()
  19. gh_flex.particles_set_velocity ()
  20. gh_flex.particles_unmap_active_indices ()
  21. gh_flex.particles_unmap_phase ()
  22. gh_flex.particles_unmap_position ()
  23. gh_flex.particles_unmap_velocity ()
  24. gh_flex.particles_update_active ()
  25. gh_flex.set_device_index ()
  26. gh_flex.shapes_create ()
  27. gh_flex.shapes_kill ()
  28. gh_flex.shapes_map ()
  29. gh_flex.shapes_set_box ()
  30. gh_flex.shapes_set_box_v2 ()
  31. gh_flex.shapes_set_mesh ()
  32. gh_flex.shapes_set_mesh_v2 ()
  33. gh_flex.shapes_set_sphere ()
  34. gh_flex.shapes_unmap ()
  35. gh_flex.solver_create ()
  36. gh_flex.solver_kill ()
  37. gh_flex.solver_set_num_active_particles ()
  38. gh_flex.solver_set_param_1f ()
  39. gh_flex.solver_set_param_1i ()
  40. gh_flex.solver_set_param_3f ()
  41. gh_flex.solver_set_param_collision_plane ()
  42. gh_flex.solver_update ()
  43. gh_flex.solver_update_params ()
  44. gh_flex.solver_write_particles ()
  45. gh_flex.solver_write_shapes ()
  46. gh_flex.start ()
  47. gh_flex.stop ()



get_compute_device_name

Description

Gets the name of the current FleX GPU.


Syntax

dev_name = gh_flex.get_compute_device_name()

Languages


Parameters

This function has no input parameter(s).


Return Values


Code sample


gpu = gh_flex.get_compute_device_name()
			


get_version

Description

Gets the version of FleX.


Syntax

v = gh_flex.get_version()

Languages


Parameters

This function has no input parameter(s).


Return Values


Code sample


v = gh_flex.get_version()
			


make_phase

Description

Generates a phase for a particle. A phase is a bit-vector that defines the behavior of a particle.


Syntax

gh_flex.make_phase(
 group,
 particle_flags,
 shape_channels
)

Languages


Parameters


Return Values

This function has no return value(s).


Code sample


-- Flags / options
--
eNvFlexPhaseSelfCollide	= 1048576 -- If set this particle will interact with particles of the same group
eNvFlexPhaseSelfCollideFilter	= 2097152 -- If set this particle will ignore collisions with particles closer than the radius in the rest pose, this flag should not be specified unless valid rest positions have been specified using NvFlexSetRestParticles()
eNvFlexPhaseFluid	= 4194304 -- If set this particle will generate fluid density constraints for its overlapping neighbors
eNvFlexPhaseGroupMask = 1048575 -- Bits [ 0, 19] represent the particle group for controlling collisions
eNvFlexPhaseFlagsMask	= 15728640 -- Bits [20, 23] hold flags about how the particle behave
eNvFlexPhaseShapeChannelMask = 2130706432 -- Bits [24, 30] hold flags representing what shape collision channels particles will collide with, see NvFlexMakeShapeFlags() (highest bit reserved for now)
eNvFlexPhaseShapeChannel0	= 16777216 -- Particle will collide with shapes 
with channel 0 set (see NvFlexMakeShapeFlags())
eNvFlexPhaseShapeChannel1 = 33554432

group = 0
particle_flags = eNvFlexPhaseSelfCollide
shape_channels = eNvFlexPhaseShapeChannelMask

phase = gh_flex.make_phase(group, particle_flags, shape_channels)
			


particles_copy_position_to_vb_fast

Description

Performs a fast copy of particles position from FleX buffer to the vertex buffer used in rendering.


Syntax

gh_flex.particles_copy_position_to_vb_fast(
 particles_id,
 vb_id,
 num_particles
)

Languages


Parameters


Return Values

This function has no return value(s).


Code sample


gh_flex.particles_copy_position_to_vb_fast(particles_id, vb_id, num_vertices)
			


particles_copy_to_vb

Description

Performs a fast copy of particles from FleX buffer to the vertex buffer used in rendering.


Syntax

gh_flex.particles_copy_to_vb(
 particles_id,
 particle_attrib,
 vb_id,
 num_particles,
 vb_start_offset_bytes,
 vb_position_stride_bytes,
 update_color_alpha,
 dt
)

Languages


Parameters


Return Values

This function has no return value(s).


Code sample


local vb_start_offset_bytes = 0
local vb_position_stride_bytes = 32
local update_color_alpha = 0
local dt = 0.016

gh_flex.particles_copy_to_vb(particles_id, "position", vb_id, num_vertices, vb_start_offset_bytes, vb_position_stride_bytes, update_color_alpha, dt)

-- particles_copy_to_vb() replaces the following code:
--
--[[
function point(buffer_ptr, index, x, y, z, r, g, b, a)
    -- Position
    local buffer_offset_bytes = index * vertex_size
    gh_utils.buffer_write_4f(buffer_ptr, buffer_offset_bytes, x, y, z, 1.0)

    -- Color
    buffer_offset_bytes = buffer_offset_bytes + attrib_size
    gh_utils.buffer_write_4f(buffer_ptr, buffer_offset_bytes, r, g, b, a)
end

gh_flex.particles_map_position(particles_id)
vb_buffer_ptr, bufsize = gh_vb.map(vb_id, "GL_WRITE_ONLY")

for i = 0, num_vertices - 1 do
    x, y, z, w = gh_flex.particles_get_position(particles_id, i)
    local alpha = particles[i+1].a
    if (update_color_alpha == 1) then
        alpha = alpha - dt
        if (alpha < 0) then
            alpha = 0
        end
    end
    particles[i+1].a = alpha
    point(vb_buffer_ptr, i, x, y, z, 1, 1, 1, alpha)
end

gh_vb.unmap(vb_id)
gh_flex.particles_unmap_position(particles_id)
--]]
			


particles_create

Description

Creates a set of particles.


Syntax

particles_id = gh_flex.particles_create(
 num_particles
)

Languages


Parameters


Return Values


Code sample


num_particles = 1000
particles_id = gh_flex.particles_create(num_particles)
			


particles_get_phase

Description

Gets the phase of a particular particle. A phase is a bit-vector that defines the behavior of a particle. See make_phase().


Syntax

phase = gh_flex.particles_get_phase(
 particles_id,
 particle_index
)

Languages


Parameters


Return Values


Code sample


phase = gh_flex.particles_get_phase(particles_id, particle_index)
			


particles_get_position

Description

Gets the position of a particular particle.


Syntax

x, y, z, w = gh_flex.particles_get_position(
 particles_id,
 particle_index
)

Languages


Parameters


Return Values


Code sample


x, y, z, w = gh_flex.particles_get_position(particles_id, particle_index)
			


particles_get_velocity

Description

Gets the velocity of a particular particle.


Syntax

x, y, z = gh_flex.particles_get_velocity(
 particles_id,
 particle_index
)

Languages


Parameters


Return Values


Code sample


x, y, z = gh_flex.particles_get_velocity(particles_id, index)
			


particles_kill

Description

Destroys a set of particles.


Syntax

gh_flex.particles_kill(
 particles_id
)

Languages


Parameters


Return Values

This function has no return value(s).


Code sample


gh_flex.particles_kill(particles_id)
			


particles_map_active_indices

Description

Maps the particles indices buffer. That allows the CPU to writes to this buffer.


Syntax

gh_flex.particles_map_active_indices(
 particles_id
)

Languages


Parameters


Return Values

This function has no return value(s).


Code sample


gh_flex.particles_map_active_indices(particles_id)
			


particles_map_phase

Description

Maps the particles phase buffer. That allows the CPU to writes to this buffer.


Syntax

gh_flex.particles_map_phase(
 particles_id
)

Languages


Parameters


Return Values

This function has no return value(s).


Code sample


gh_flex.particles_map_phase(particles_id)
			


particles_map_position

Description

Maps the particles position buffer. That allows the CPU to writes to this buffer.


Syntax

gh_flex.particles_map_position(
 particles_id
)

Languages


Parameters


Return Values

This function has no return value(s).


Code sample


gh_flex.particles_map_position(particles_id)
			


particles_map_velocity

Description

Maps the particles velocity buffer. That allows the CPU to writes to this buffer.


Syntax

gh_flex.particles_map_velocity(
 particles_id
)

Languages


Parameters


Return Values

This function has no return value(s).


Code sample


gh_flex.particles_map_velocity(particles_id)
			


particles_set_active_index

Description

Sets which particle is active.


Syntax

gh_flex.particles_set_active_index(
 particles_id,
 index,
 particle_index
)

Languages


Parameters


Return Values

This function has no return value(s).


Code sample


-- All the following code can be replaced by one call to particles_update_active()

-- Usually particles_set_active_index() is used as follows:
--

gh_flex.particles_map_active_indices(particles_id)

for i = 0, num_particles - 1 do
    gh_flex.particles_set_active_index(particles_id, i, i)
end

gh_flex.particles_unmap_active_indices(particles_id)
gh_flex.particles_set_num_active_indices(particles_id, num_particles)

-- Upload to GPU
gh_flex.solver_write_particles(solver_id, particles_id)
			


particles_set_num_active_indices

Description

Sets the number of active particles.


Syntax

gh_flex.particles_set_num_active_indices(
 particles_id,
 num_active
)

Languages


Parameters


Return Values

This function has no return value(s).


Code sample


gh_flex.particles_set_num_active_indices(particles_id, num_active)
			


particles_set_phase

Description

Sets the phase of a particle. The phase is a bit-vector that defines the behavior of a particle. Use the function make_phase() to generate a phase.


Syntax

gh_flex.particles_set_phase(
 particles_id,
 particle_index,
 phase
)

Languages


Parameters


Return Values

This function has no return value(s).


Code sample


gh_flex.particles_map_position(particles_id)
gh_flex.particles_map_velocity(particles_id)
gh_flex.particles_map_phase(particles_id)

phase = gh_flex.make_phase(...)

for i = 0, num_particles - 1 do
    x = random(...)
    y = random(...)
    z = random(...)

    -- Mass = 1.0
    w = 1.0
    gh_flex.particles_set_position(particles_id, i, x, y, z, w)

    -- Initial velocity is zero
    gh_flex.particles_set_velocity(particles_id, i, 0.0, 0.0, 0.0)
    gh_flex.particles_set_phase(particles_id, i, phase)
end

gh_flex.particles_unmap_phase(particles_id)
gh_flex.particles_unmap_velocity(particles_id)
gh_flex.particles_unmap_position(particles_id)

-- Upload to GPU
gh_flex.solver_write_particles(solver_id, particles_id)
			


particles_set_position

Description

Sets the position of a particle.


Syntax

gh_flex.particles_set_position(
 particles_id,
 particle_index,
 x, y, z, w
)

Languages


Parameters


Return Values

This function has no return value(s).


Code sample


gh_flex.particles_map_position(particles_id)

for i = 0, num_particles - 1 do
    x = random(...)
    y = random(...)
    z = random(...)

    -- Mass = 1.0
    w = 1.0
    gh_flex.particles_set_position(particles_id, i, x, y, z, w)
end

gh_flex.particles_unmap_position(particles_id)

-- Upload to GPU
gh_flex.solver_write_particles(solver_id, particles_id)
			


particles_set_velocity

Description

Sets the velocity of a particle.


Syntax

gh_flex.particles_set_velocity(
 particles_id,
 particle_index,
 x, y, z
)

Languages


Parameters


Return Values

This function has no return value(s).


Code sample


gh_flex.particles_map_position(particles_id)
gh_flex.particles_map_velocity(particles_id)

for i = 0, num_particles - 1 do
    x = random(...)
    y = random(...)
    z = random(...)

    -- Mass = 1.0
    w = 1.0
    gh_flex.particles_set_position(particles_id, i, x, y, z, w)

    -- Initial velocity is zero.
    gh_flex.particles_set_velocity(particles_id, i, 0.0, 0.0, 0.0)
end

gh_flex.particles_unmap_velocity(particles_id)
gh_flex.particles_unmap_position(particles_id)

-- Upload to GPU
gh_flex.solver_write_particles(solver_id, particles_id)
			


particles_unmap_active_indices

Description

Unmaps the particles indices buffer.


Syntax

gh_flex.particles_unmap_active_indices(
 particles_id
)

Languages


Parameters


Return Values

This function has no return value(s).


Code sample


gh_flex.particles_unmap_active_indices(particles_id)
			


particles_unmap_phase

Description

Unmaps the particles phase buffer.


Syntax

gh_flex.particles_unmap_phase(
 particles_id
)

Languages


Parameters


Return Values

This function has no return value(s).


Code sample


gh_flex.particles_unmap_phase(particles_id)
			


particles_unmap_position

Description

Unmaps the particles position buffer.


Syntax

gh_flex.particles_unmap_position(
 particles_id
)

Languages


Parameters


Return Values

This function has no return value(s).


Code sample


gh_flex.particles_unmap_position(particles_id)
			


particles_unmap_velocity

Description

Unmaps the particles velocity buffer.


Syntax

gh_flex.particles_unmap_velocity(
 particles_id
)

Languages


Parameters


Return Values

This function has no return value(s).


Code sample


gh_flex.particles_unmap_velocity(particles_id)
			


particles_update_active

Description

Updates all active particles in a single function.


Syntax

gh_flex.particles_update_active(
 particles_id,
 num_active_particles
)

Languages


Parameters


Return Values

This function has no return value(s).


Code sample


gh_flex.particles_update_active(particles_id, num_active_particles)

-- particles_update_active() replaces the following code:
--
--[[
gh_flex.particles_set_num_active_indices(particles_id, num_vertices)
gh_flex.particles_map_active_indices(particles_id)

for i = 0, num_vertices - 1 do
    gh_flex.particles_set_active_index(particles_id, i, i)
end

gh_flex.particles_unmap_active_indices(particles_id)
--]]
			


set_device_index

Description

Sets the device index. This function allows to select a particular FleX GPU. Use -1 to auto-select the default PhysX accelerator in NVIDIA control panel.


Syntax

gh_flex.set_device_index(
 i
)

Languages


Parameters


Return Values

This function has no return value(s).


Code sample


gh_flex.set_device_index(-1)
			


shapes_create

Description

Creates a set of collision shapes.


Syntax

shapes_id = gh_flex.shapes_create(
 num_shapes
)

Languages


Parameters


Return Values


Code sample


num_shapes = 2
shapes_id = gh_flex.shapes_create(num_shapes)
			


shapes_kill

Description

Destroys a set of shapes.


Syntax

gh_flex.shapes_kill(
 shapes_id
)

Languages


Parameters


Return Values

This function has no return value(s).


Code sample


gh_flex.shapes_kill(shapes_id)
			


shapes_map

Description

Maps a shapes buffer. That allows the CPU to writes to this buffer.


Syntax

gh_flex.shapes_map(
 shapes_id
)

Languages


Parameters


Return Values

This function has no return value(s).


Code sample


gh_flex.shapes_map(shapes_id)
			


shapes_set_box

Description

Sets a box collision shape.


Syntax

gh_flex.shapes_set_box(
 shapes_id,
 shape_index,
 shape_channels,
 width, height, depth,
 x, y, z,
 qx, qy, qz, qw
)

Languages


Parameters


Return Values

This function has no return value(s).


Code sample


gh_flex.shapes_map(shapes_id)
shape_index = 0
shape_channels = eNvFlexPhaseShapeChannel0
width = 2.0
height = 2.0
depth = 2.0
gh_flex.shapes_set_box(shapes_id, shape_index, shape_channels,  width, height, depth,  0.0, 1.0, 0.0,  0.0, 0.0, 0.0, 1.0)
gh_flex.shapes_unmap(shapes_id)
			


shapes_set_box_v2

Description

Sets a box collision shape.


Syntax

gh_flex.shapes_set_box_v2(
 shapes_id,
 shape_index,
 shape_channels,
 width, height, depth,
 x, y, z,
 pitch, yaw, roll
)

Languages


Parameters


Return Values

This function has no return value(s).


Code sample


gh_flex.shapes_map(shapes_id)

shape_index = 0
shape_channels = eNvFlexPhaseShapeChannel0
width = 2.0
height = 2.0
depth = 2.0

gh_flex.shapes_set_box_v2(shapes_id, shape_index, shape_channels,  width, height, depth,  0.0, 1.0, 0.0,  0.0, 0.0, 0.0)

gh_flex.shapes_unmap(shapes_id)
			


shapes_set_mesh

Description

Sets a mesh collision shape.


Syntax

gh_flex.shapes_set_mesh(
 shapes_id,
 shape_index,
 shape_channels,
 mesh_id,
 x, y, z,
 qx, qy, qz, qw
)

Languages


Parameters


Return Values

This function has no return value(s).


Code sample


gh_flex.shapes_map(shapes_id)

shape_index = 0
shape_channels = eNvFlexPhaseShapeChannel0
mesh_id = gh_mesh.create_torus(2.0, 0.4, 20)

gh_flex.shapes_set_mesh(shapes_id, shape_index, shape_channels,  mesh_id,  0.0, 2.0, 0.0,  0.0, 0.0, 0.0, 1.0)

gh_flex.shapes_unmap(shapes_id)
			


shapes_set_mesh_v2

Description

Sets a mesh collision shape.


Syntax

gh_flex.shapes_set_mesh_v2(
 shapes_id,
 shape_index,
 shape_channels,
 mesh_id,
 x, y, z,
 pitch, yaw, roll
)

Languages


Parameters


Return Values

This function has no return value(s).


Code sample


gh_flex.shapes_map(shapes_id)

shape_index = 0
shape_channels = eNvFlexPhaseShapeChannel0
mesh_id = gh_mesh.create_torus(2.0, 0.4, 20)

gh_flex.shapes_set_mesh_v2(shapes_id, shape_index, shape_channels,  mesh_id,  0.0, 2.0, 0.0,  0.0, 0.0, 0.0)

gh_flex.shapes_unmap(shapes_id)
			


shapes_set_sphere

Description

Sets a sphere collision shape.


Syntax

gh_flex.shapes_set_sphere(
 shapes_id,
 shape_index,
 shape_channels,
 radius,
 x, y, z
)

Languages


Parameters


Return Values

This function has no return value(s).


Code sample


gh_flex.shapes_map(shapes_id)

shape_index = 0
shape_channels = eNvFlexPhaseShapeChannel0
radius = 2.0

gh_flex.shapes_set_sphere(shapes_id, shape_index, shape_channels, radius, 0.0, 3.0, 0.0)

gh_flex.shapes_unmap(shapes_id)
			


shapes_unmap

Description

Unmaps the shapes buffer.


Syntax

gh_flex.shapes_unmap(
 shapes_id
)

Languages


Parameters


Return Values

This function has no return value(s).


Code sample


gh_flex.shapes_unmap(shapes_id)
			


solver_create

Description

Creates a FleX solver.


Syntax

solver_id = gh_flex.solver_create(
 max_particles
)

Languages


Parameters


Return Values


Code sample


max_particles = 1000
solver_id = gh_flex.solver_create(max_particles)
			


solver_kill

Description

Destroys a FleX solver.


Syntax

gh_flex.solver_kill(
 solver_id
)

Languages


Parameters


Return Values

This function has no return value(s).


Code sample


gh_flex.solver_kill(solver_id)
			


solver_set_num_active_particles

Description

Sets the number of active particles.


Syntax

gh_flex.solver_set_num_active_particles(
 solver_id,
 num_active_particles
)

Languages


Parameters


Return Values

This function has no return value(s).


Code sample


gh_flex.solver_set_num_active_particles(solver_id, num_active_particles)
			


solver_set_param_1f

Description

Set a solver parameter.


Syntax

gh_flex.solver_set_param_1f(
 solver_id,
 param_name,
 x
)

Languages


Parameters


Return Values

This function has no return value(s).


Code sample


params = [[
float radius;						//!< The maximum interaction radius for particles
float solidRestDistance;			//!< The distance non-fluid particles attempt to maintain from each other, must be in the range (0, radius]
float fluidRestDistance;			//!< The distance fluid particles are spaced at the rest density, must be in the range (0, radius], for fluids this should generally be 50-70% of mRadius, for rigids this can simply be the same as the particle radius
// common params
float dynamicFriction;				//!< Coefficient of friction used when colliding against shapes
float staticFriction;				//!< Coefficient of static friction used when colliding against shapes
float particleFriction;				//!< Coefficient of friction used when colliding particles
float restitution;					//!< Coefficient of restitution used when colliding against shapes, particle collisions are always inelastic
float adhesion;						//!< Controls how strongly particles stick to surfaces they hit, default 0.0, range [0.0, +inf]
float sleepThreshold;				//!< Particles with a velocity magnitude < this threshold will be considered fixed
float maxSpeed;						//!< The magnitude of particle velocity will be clamped to this value at the end of each step
float maxAcceleration;				//!< The magnitude of particle acceleration will be clamped to this value at the end of each step (limits max velocity change per-second), useful to avoid popping due to large interpenetrations
float shockPropagation;				//!< Artificially decrease the mass of particles based on height from a fixed reference point, this makes stacks and piles converge faster
float dissipation;					//!< Damps particle velocity based on how many particle contacts it has
float damping;						//!< Viscous drag force, applies a force proportional, and opposite to the particle velocity
// cloth params
float drag;							//!< Drag force applied to particles belonging to dynamic triangles, proportional to velocity^2*area in the negative velocity direction
float lift;							//!< Lift force applied to particles belonging to dynamic triangles, proportional to velocity^2*area in the direction perpendicular to velocity and (if possible), parallel to the plane normal
// fluid params
float cohesion;						//!< Control how strongly particles hold each other together, default: 0.025, range [0.0, +inf]
float surfaceTension;				//!< Controls how strongly particles attempt to minimize surface area, default: 0.0, range: [0.0, +inf]
float viscosity;					//!< Smoothes particle velocities using XSPH viscosity
float vorticityConfinement;			//!< Increases vorticity by applying rotational forces to particles
float anisotropyScale;				//!< Control how much anisotropy is present in resulting ellipsoids for rendering, if zero then anisotropy will not be calculated, see NvFlexGetAnisotropy()
float anisotropyMin;				//!< Clamp the anisotropy scale to this fraction of the radius
float anisotropyMax;				//!< Clamp the anisotropy scale to this fraction of the radius
float smoothing;					//!< Control the strength of Laplacian smoothing in particles for rendering, if zero then smoothed positions will not be calculated, see NvFlexGetSmoothParticles()
float solidPressure;				//!< Add pressure from solid surfaces to particles
float freeSurfaceDrag;				//!< Drag force applied to boundary fluid particles
float buoyancy;						//!< Gravity is scaled by this value for fluid particles
// diffuse params
float diffuseThreshold;				//!< Particles with kinetic energy + divergence above this threshold will spawn new diffuse particles
float diffuseBuoyancy;				//!< Scales force opposing gravity that diffuse particles receive
float diffuseDrag;					//!< Scales force diffuse particles receive in direction of neighbor fluid particles
float diffuseLifetime;				//!< Time in seconds that a diffuse particle will live for after being spawned, particles will be spawned with a random lifetime in the range [0, diffuseLifetime]
// collision params
float collisionDistance;			//!< Distance particles maintain against shapes, note that for robust collision against triangle meshes this distance should be greater than zero
float particleCollisionMargin;		//!< Increases the radius used during neighbor finding, this is useful if particles are expected to move significantly during a single step to ensure contacts aren't missed on subsequent iterations
float shapeCollisionMargin;			//!< Increases the radius used during contact finding against kinematic shapes
float relaxationFactor;				//!< Control the convergence rate of the parallel solver, default: 1, values greater than 1 may lead to instability
]]

gh_flex.solver_set_param_1f(solver_id, "radius", 0.1)
gh_flex.solver_set_param_1f(solver_id, "dynamicFriction", 0.15)
			


solver_set_param_1i

Description

Set a solver parameter.


Syntax

gh_flex.solver_set_param_1i(
 solver_id,
 param_name,
 x
)

Languages


Parameters


Return Values

This function has no return value(s).


Code sample


params = [[
int numIterations;					//!< Number of solver iterations to perform per-substep
int diffuseBallistic;				//!< The number of neighbors below which a diffuse particle is considered ballistic
int numPlanes;						//!< Num collision planes
]]

gh_flex.solver_set_param_1i(solver_id, "numIterations", 2)
			


solver_set_param_3f

Description

Set a solver parameter.


Syntax

gh_flex.solver_set_param_3f(
 solver_id,
 param_name,
 x, y, z
)

Languages


Parameters


Return Values

This function has no return value(s).


Code sample


params = [[
float gravity[3];					//!< Constant acceleration applied to all particles
// cloth params
float wind[3];						//!< Constant acceleration applied to particles that belong to dynamic triangles, drag needs to be > 0 for wind to affect triangles
]]

gh_flex.solver_set_param_1f(solver_id, "gravity", 0.0, -10.0, 0.0)
			


solver_set_param_collision_plane

Description

Set a collision plane (a particular solver parameter). FleX has a max 8 collision planes.


Syntax

gh_flex.solver_set_param_collision_plane(
 solver_id,
 plane_index,
 a, b, c, d
)

Languages


Parameters


Return Values

This function has no return value(s).


Code sample


gh_flex.solver_set_param_1i(solver_id, "numPlanes", 1)

plane_index = 0
gh_flex.solver_set_param_collision_plane(solver_id, plane_index, 0.0, 1.0, 0.0, 0.0)
			


solver_update

Description

Updates a solver: runs the simulation.


Syntax

gh_flex.solver_update(
 solver_id,
 dt,
 substeps
)

Languages


Parameters


Return Values

This function has no return value(s).


Code sample


substeps = 2
gh_flex.solver_update(solver_id, dt, substeps)
			


solver_update_params

Description

Writes params (update) to GPU.


Syntax

gh_flex.solver_update_params(
 solver_id
)

Languages


Parameters


Return Values

This function has no return value(s).


Code sample


gh_flex.solver_update_params(solver_id)
			


solver_write_particles

Description

Sets / writes particles to GPU.


Syntax

gh_flex.solver_write_particles(
 solver_id,
 particles_id
)

Languages


Parameters


Return Values

This function has no return value(s).


Code sample


num_particles = 1000

particles_id = gh_flex.particles_create(num_particles)
...
gh_flex.solver_write_particles(solver_id, particles_id)
			


solver_write_shapes

Description

Sets / writes collision shapes to GPU.


Syntax

gh_flex.solver_write_shapes(
 solver_id,
 shapes_id
)

Languages


Parameters


Return Values

This function has no return value(s).


Code sample


num_shapes = 2

shapes_id = gh_flex.shapes_create(num_shapes)
...
gh_flex.solver_write_shapes(solver_id, shapes_id)
			


start

Description

Starts the FleX engine. Must be called first. No-op if called twice.


Syntax

state = gh_flex.start()

Languages


Parameters

This function has no input parameter(s).


Return Values


Code sample


flex_ok = gh_flex.start()

if (flex_ok == 0) then
    -- error
end
			


stop

Description

Stops the FleX engine. Must be called at the end of the application (TERMINATE script is a good place).


Syntax

state = gh_flex.stop()

Languages


Parameters

This function has no input parameter(s).


Return Values


Code sample


state = gh_flex.stop()
			






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