diff options
| -rw-r--r-- | release/scripts/startup/bl_ui/properties_particle.py | 7 | ||||
| -rw-r--r-- | source/blender/makesdna/DNA_cloth_types.h | 4 | ||||
| -rw-r--r-- | source/blender/makesrna/intern/rna_cloth.c | 14 | ||||
| -rw-r--r-- | source/blender/physics/intern/BPH_mass_spring.cpp | 9 | ||||
| -rw-r--r-- | source/blender/physics/intern/hair_volume.cpp | 25 | ||||
| -rw-r--r-- | source/blender/physics/intern/implicit.h | 2 |
6 files changed, 39 insertions, 22 deletions
diff --git a/release/scripts/startup/bl_ui/properties_particle.py b/release/scripts/startup/bl_ui/properties_particle.py index 690a9d1d8bd..e6e7e1fb43c 100644 --- a/release/scripts/startup/bl_ui/properties_particle.py +++ b/release/scripts/startup/bl_ui/properties_particle.py @@ -325,10 +325,9 @@ class PARTICLE_PT_hair_dynamics(ParticleButtonsPanel, Panel): col.label(text="Volume") col.prop(cloth, "air_damping", text="Air Drag") col.prop(cloth, "internal_friction", slider=True) - sub = col.row(align=True) - # XXX disabled due to stability issues - #sub.prop(cloth, "pressure", slider=True, text="Pressure") - #sub.prop(cloth, "pressure_threshold", slider=True, text="Threshold") + sub = col.column(align=True) + sub.prop(cloth, "density_target", text="Density Target") + sub.prop(cloth, "density_strength", slider=True, text="Strength") col.prop(cloth, "voxel_cell_size") split.separator() diff --git a/source/blender/makesdna/DNA_cloth_types.h b/source/blender/makesdna/DNA_cloth_types.h index f4d8faa7958..3144dadb680 100644 --- a/source/blender/makesdna/DNA_cloth_types.h +++ b/source/blender/makesdna/DNA_cloth_types.h @@ -69,8 +69,8 @@ typedef struct ClothSimSettings { float goalspring; float goalfrict; float velocity_smooth; /* smoothing of velocities for hair */ - float pressure; /* pressure factor from hair density */ - float pressure_threshold; /* minimum density for hair pressure */ + float density_target; /* minimum density for hair */ + float density_strength; /* influence of hair density */ float collider_friction; /* friction with colliders */ float vel_damping; /* damp the velocity to speed up getting to the resting position */ float shrink_min; /* min amount to shrink cloth by 0.0f (no shrink) - 1.0f (shrink to nothing) */ diff --git a/source/blender/makesrna/intern/rna_cloth.c b/source/blender/makesrna/intern/rna_cloth.c index 1176da7642c..c31287097f6 100644 --- a/source/blender/makesrna/intern/rna_cloth.c +++ b/source/blender/makesrna/intern/rna_cloth.c @@ -385,16 +385,16 @@ static void rna_def_cloth_sim_settings(BlenderRNA *brna) RNA_def_property_ui_text(prop, "Collider Friction", ""); RNA_def_property_update(prop, 0, "rna_cloth_update"); - prop = RNA_def_property(srna, "pressure", PROP_FLOAT, PROP_NONE); - RNA_def_property_float_sdna(prop, NULL, "pressure"); - RNA_def_property_range(prop, 0.0f, 1000.0f); - RNA_def_property_ui_text(prop, "Internal Pressure", "Generate outward force based on hair density"); + prop = RNA_def_property(srna, "density_target", PROP_FLOAT, PROP_NONE); + RNA_def_property_float_sdna(prop, NULL, "density_target"); + RNA_def_property_range(prop, 0.0f, 1000000.0f); + RNA_def_property_ui_text(prop, "Target Density", "Maximum density of hair"); RNA_def_property_update(prop, 0, "rna_cloth_update"); - prop = RNA_def_property(srna, "pressure_threshold", PROP_FLOAT, PROP_NONE); - RNA_def_property_float_sdna(prop, NULL, "pressure_threshold"); + prop = RNA_def_property(srna, "density_strength", PROP_FLOAT, PROP_NONE); + RNA_def_property_float_sdna(prop, NULL, "density_strength"); RNA_def_property_range(prop, 0.0f, 1000.0f); - RNA_def_property_ui_text(prop, "Internal Pressure Threshold", "No pressure force is generated below this pressure value"); + RNA_def_property_ui_text(prop, "Target Density Strength", "Influence of target density on the simulation"); RNA_def_property_update(prop, 0, "rna_cloth_update"); /* mass */ diff --git a/source/blender/physics/intern/BPH_mass_spring.cpp b/source/blender/physics/intern/BPH_mass_spring.cpp index a20f1617505..d911a431b23 100644 --- a/source/blender/physics/intern/BPH_mass_spring.cpp +++ b/source/blender/physics/intern/BPH_mass_spring.cpp @@ -1017,8 +1017,8 @@ static void cloth_continuum_step(ClothModifierData *clmd, float dt) const float fluid_factor = 0.95f; /* blend between PIC and FLIP methods */
float smoothfac = parms->velocity_smooth;
- float pressfac = parms->pressure;
- float minpress = parms->pressure_threshold;
+ float denstarget = parms->density_target;
+ float densfac = parms->density_strength;
float gmin[3], gmax[3];
int i;
@@ -1030,14 +1030,15 @@ static void cloth_continuum_step(ClothModifierData *clmd, float dt) hair_get_boundbox(clmd, gmin, gmax);
/* gather velocities & density */
- if (smoothfac > 0.0f || pressfac > 0.0f) {
+ if (smoothfac > 0.0f || densfac > 0.0f) {
HairGrid *grid = BPH_hair_volume_create_vertex_grid(clmd->sim_parms->voxel_cell_size, gmin, gmax);
BPH_hair_volume_set_debug_data(grid, clmd->debug_data);
+// BPH_hair_volume_set_debug_value(grid, (int)(spring2->ij == clmd->sim_parms->density_target));
cloth_continuum_fill_grid(grid, cloth);
/* main hair continuum solver */
- BPH_hair_volume_solve_divergence(grid, dt);
+ BPH_hair_volume_solve_divergence(grid, dt, denstarget, densfac);
for (i = 0, vert = cloth->verts; i < numverts; i++, vert++) {
float x[3], v[3], nv[3];
diff --git a/source/blender/physics/intern/hair_volume.cpp b/source/blender/physics/intern/hair_volume.cpp index 5dadd45c154..4d10c042f46 100644 --- a/source/blender/physics/intern/hair_volume.cpp +++ b/source/blender/physics/intern/hair_volume.cpp @@ -530,10 +530,22 @@ void BPH_hair_volume_normalize_vertex_grid(HairGrid *grid) } } -bool BPH_hair_volume_solve_divergence(HairGrid *grid, float dt) +static const float density_threshold = 0.001f; /* cells with density below this are considered empty */ + +/* Contribution of target density pressure to the laplacian in the pressure poisson equation. + * This is based on the model found in + * "Two-way Coupled SPH and Particle Level Set Fluid Simulation" (Losasso et al., 2008) + */ +BLI_INLINE float hair_volume_density_divergence(float density, float target_density, float strength) +{ + if (density > density_threshold && density > target_density) + return strength * density * logf(target_density / density); + else + return 0.0f; +} + +bool BPH_hair_volume_solve_divergence(HairGrid *grid, float dt, float target_density, float target_strength) { - const float density_threshold = 0.001f; /* cells with density below this are considered empty */ - const float flowfac = grid->cellsize / dt; const float inv_flowfac = dt / grid->cellsize; @@ -576,12 +588,17 @@ bool BPH_hair_volume_solve_divergence(HairGrid *grid, float dt) float dy = vert_py->velocity[1] - v[1]; float dz = vert_pz->velocity[2] - v[2]; + float divergence = (dx + dy + dz) * flowfac; + + /* adjustment term for target density */ + float target = hair_volume_density_divergence(vert->density, target_density, target_strength); + /* B vector contains the finite difference approximation of the velocity divergence. * Note: according to the discretized Navier-Stokes equation the rhs vector * and resulting pressure gradient should be multiplied by the (inverse) density; * however, this is already included in the weighting of hair velocities on the grid! */ - B[u] = (dx + dy + dz) * flowfac; + B[u] = divergence + target; } } } diff --git a/source/blender/physics/intern/implicit.h b/source/blender/physics/intern/implicit.h index 203e6f3c235..246b916e353 100644 --- a/source/blender/physics/intern/implicit.h +++ b/source/blender/physics/intern/implicit.h @@ -187,7 +187,7 @@ void BPH_hair_volume_add_segment(struct HairGrid *grid, void BPH_hair_volume_normalize_vertex_grid(struct HairGrid *grid); -bool BPH_hair_volume_solve_divergence(struct HairGrid *grid, float dt); +bool BPH_hair_volume_solve_divergence(struct HairGrid *grid, float dt, float target_density, float target_strength); #if 0 /* XXX weighting is incorrect, disabled for now */ void BPH_hair_volume_vertex_grid_filter_box(struct HairVertexGrid *grid, int kernel_size); #endif |