This patch add SPH (Smoothed Particle Hydrodynamics)fluid dynamics to the
blender particle system. SPH is an boundless Lagrangian interpolation
technique to solve the fluid motion equations.
From liquids to sand, goo and gases could be simulated using the particle
system.
It features internal viscosity, a double density relaxation that accounts
for surface tension effects, static internal springs for plastic fluids,
and buoyancy for gases.
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This is a commit of the core fluid physics. Raul will work on proper
documentation soon and more features such as surface extraction from
the particle point cloud and increasing stability by sub-frame calculations
later.
levels, child particles, and shadow/SSS/AO quality.. Now also works on what
is displayed in the 3d view instead of only rendering, see panel in the scene
properties.
Most file changes were to make scene available in the isDisabled modifier
callback function.
* The hair mesh vertex index was stored as a short, but vertex counts can easily go higher than what fits in a short so changed this to an int.
* Also removed particle life looping, which didn't work correctly anyways. Similar functionality will become available when I get to recoding reactor particles into a better system.
* Make partial update work again for faster editing.
* Draw parents over children again, nicer for editing.
* Fix crash with remove tools & showing child particles.
* Fix children not disappearing always when setting to None.
* Fix wrong normal for last point in child path.
* Fix a python error in the hair dynamics panel.
* Now uses the CCG DerivedMesh also in object mode, used to be edit mode only.
* Create CD_ORIGINDEX layer on demand, to save memory.
* Removed ss_to_cdderivedmesh function, and instead create ccgdm and then
convert that to cddm, to avoid code duplication.
* Added and implement DerivedMesh interface functions to obtain face grids.
* Store edge/face flags more memory efficient.
* Export CCGDerivedMesh struct in BKE_subsurf.h
* Convert all code to use new functions.
* Branch maintainers may want to skip this commit, and run this
conversion script instead, if they use a lot of math functions
in new code:
http://www.pasteall.org/9052/python
The goodies:
* Curves can be used as normal dynamic effectors too with
the new "curve" field shape.
* Group visualization has optional duplication counts for
each object in the specified group.
* Object & group visualizations, which are done without
taking the dupliobject's global position into account
(unless the whole group is used). This is much nicer than
the previous behavior, but I added a "Use Global Location"
option for those who want to use it the old way.
* The active particle system's particles are now drawn a
with theme coloured outline instead of pure white.
* Added object aligned velocity factors (buttons categorized
and re-organized too).
Bug fixes:
* Absorption didn't work as the ui toggle button was forgotten.
* Some other force field ui tweaks.
* Crash after adding children and changing trails count.
* Display types "cross" and "axis" crashed.
* Particles weren't drawn with correct coloring.
* Billboards didn't update properly in viewport to camera
location changes.
* Particle rotation wasn't recreated correctly from point cache.
* Changing particles amount crashed sometimes.
* Some files with child hair crashed on loading.
* Compiler warning fixes.
* Adding boids crashed on frame 1;
* Unified scene wide gravity (currently in scene buttons)
instead of each simulation having it's own gravity.
* Weight parameters for all effectors and an effector group
setting.
* Every effector can use noise.
* Most effectors have "shapes" point, plane, surface, every point.
- "Point" is most like the old effectors and uses the
effector location as the effector point.
- "Plane" uses the closest point on effectors local xy-plane
as the effector point.
- "Surface" uses the closest point on an effector object's
surface as the effector point.
- "Every Point" uses every point in a mesh effector object
as an effector point.
- The falloff is calculated from this point, so for example
with "surface" shape and "use only negative z axis" it's
possible to apply force only "inside" the effector object.
* Spherical effector is now renamed as "force" as it's no longer
just spherical.
* New effector parameter "flow", which makes the effector act as
surrounding air velocity, so the resulting force is
proportional to the velocity difference of the point and "air
velocity". For example a wind field with flow=1.0 results in
proper non-accelerating wind.
* New effector fields "turbulence", which creates nice random
flow paths, and "drag", which slows the points down.
* Much improved vortex field.
* Effectors can now effect particle rotation as well as location.
* Use full, or only positive/negative z-axis to apply force
(note. the z-axis is the surface normal in the case of
effector shape "surface")
* New "force field" submenu in add menu, which adds an empty
with the chosen effector (curve object for corve guides).
* Other dynamics should be quite easy to add to the effector
system too if wanted.
* "Unified" doesn't mean that force fields give the exact same results for
particles, softbody & cloth, since their final effect depends on many external
factors, like for example the surface area of the effected faces.
Code changes
* Subversion bump for correct handling of global gravity.
* Separate ui py file for common dynamics stuff.
* Particle settings updating is flushed with it's id through
DAG_id_flush_update(..).
Known issues
* Curve guides don't yet have all ui buttons in place, but they
should work none the less.
* Hair dynamics don't yet respect force fields.
Other changes
* Particle emission defaults now to frames 1-200 with life of 50
frames to fill the whole default timeline.
* Many particles drawing related crashes fixed.
* Sometimes particles didn't update on first frame properly.
* Hair with object/group visualization didn't work properly.
* Memory leaks with PointCacheID lists (Genscher, remember to
free pidlists after use :).
* VecLerp3f and Vec2Lerp3f - interpolate 3 2d/3d vectors from 3 weights
* AngleToLength(angle) - useful for making even width shell/walls based on the angles of the surrounding geometry from each point. (same method used in 2.4x python solidify script).
also quiet some warnings.
New stuff
- Bending springs for hair dynamics.
Code cleanup & optimization
- Disabled reactor particles temporarily for cleanup, it's a clumsy system that will be replaced with something better.
- Removed child seams, something better will come here too :)
- Normal particle drawing data is now saved between redraws if the particles don't move between redraws.
* For example rotating the 3d view is now realtime even with 1M particles.
- Many random values for particles now come from a lookup table making things much faster.
- Most accessed small point cache functions are now much faster as macros.
- Lot's of general code cleanup.
- Nothing big should have changed so if something doesn't work like it used to it's probably just a typo somewhere :)
Note sure what to do with this one, and personally think
we should avoid using macros for this kind of thing:
V_GROW(edges);
source/blender/editors/mesh/loopcut.c:232: warning: value computed is not used
- use_radius option, off by default for 2.4x files, on by default on new curves.
- curve deform modifiers (think tentacles)
- follow path (parent mode and constraint)
- curve guides
- added back Alt+S to scale point radius
- Mat3Scale and Mat4Scale arithb.c functions to make a new uniform scale matrix.
- TODO, effectors, looks like they have no way to scale from the radius yet.
- Hair dynamics have their own panel in particle settings with the settings from cloth panel that apply to hair.
- Basic internal friction force to quickly emulate self collisions and volume preservation. (Still very early code, but gives some idea of what's possible).
- Softbody simulation is no longer used for hair.
* Old files with sb dynamics should just load the hair without dynamics so new dynamics can be applied.
* Invasion of particles exceptions in sb code is finally over.
- Collisions with other objects are disabled for now and will be worked out in the future.
Other changes/fixes:
- Particle mode editing flag wasn't saved properly.
- Some old files with edited hair didn't load correctly.
- Disabled delete & specials menu in particle mode for non-hair editing.
- Fixed yet one more cloth & softbody pointcache update issue.
- Disconnect/connect hair now uses only the deformed mesh so it works correctly also for subsurfed emitters.
- Hair editing now updates correctly with a moving emitter.
- Moves hair from face-space to global space and back.
- Allows for editing of emitter mesh after hair combing.
- Disconnect hair before doing topology changing changes in mesh edit mode, connect after changes.
- Notes:
* The closest location on emitter surface to the hair root is used to connect the hair.
* Emitter deflection, sticky roots and add brush don't apply for disconnect hair in particle mode.
- Todo for future:
* Copy disconnected hair from object to another (when 2.5 has proper copy operators again).
* Possible automatic disconnect/connect with topology changing operations in mesh edit mode.
Other changes/fixes:
- Proper subtypes for some particle mode notifiers.
- Particle mode selections didn't draw correctly because of using lighting for the paths.
- Some big refresh issues with softbody & cloth point cache usage should now be fixed.
- Removed sticky objects from particles (better stuff will come back when I get to updating reactor particles).
- Some initial easy memory efficiency cleanup for ParticleData struct. The ultimate goal is to get particles less memory hungry -> more particles possible in single scene.
- Wrong path timing clamping caused hair particles to seem disappeared when changing between normal<->hair particles.
- "Calculate to current frame" in cache buttons baked instead of the intended function.
- Boids particle data is now a bit better organized.
- Baked point caches for particles, cloth and softbody can now be edited in particle mode.
* This overwrites the old cloth/sb cache editmode editing.
* The type of editable system is chosen from a menu.
* For particles the current particle system and it's current cache are used.
- Currently this only works for caches that are in memory, but some automatic conversion from disk to memory and back can be implemented later.
- All tools from hair editing can't be applied to point caches and are hidden in the tool panel and specials menu. Some functionality like subdividing paths can be later implemented in a slightly different way from how it works for hair.
- Code is not yet optimized for speed, so editing might be slow sometimes.
Known issues:
- Cloth doesn't update properly while in particle mode, due to the way cloth modifier currently works. Daniel can you check on this?
- As "particle mode" is not only for particles any more some other name would be in place?
- Better icons are needed for the path, point, and tip-modes as the current icons from mesh edit mode are quite misleading.
- Direct editing of point velocities is not yet implemented, but will be in the future.
Other changes:
- Hair editing doesn't require a "make editable" button press any more.
- Multiple caches in single particle system disables changing emission properties.
- Unified ui code for all point cache panels.
* Defined in buttons_particle.py and imported for cloth, smoke & softbody.
- Proper disabling of properties in ui after baking point caches. (Daniel could you please make needed disable code for smoke panels as their functionality is not familiar to me.)
- Hair weight brush has been removed. Once hair dynamics is re-implemented I'll code a more useable alternative to the functionality.
Bug fixes:
- Unlinking particle settings crashed.
- Deleting the active object with particles in the scene crashed.
- Softbody didn't write point caches correctly on save.
Also, made the Outliner's horizontal scrollbar work better for keymaps view. It's still using an approximation of the width, but at least you can scroll now.
* Weightpaint is now object-local like sculpt and vertexpaint.
* Fixed a bug spotted by DingTo, going from editmode to sculptmode didn't fully leave editmode
- HEADER (beginning of each file)
* general header:
+ 8 char: "BPHYSICS"
+ 1 int: simulation type (same as PTCacheID->type)
* custom header (same for sb, particles and cloth, but can be different for new dynamics)
+ 1 int: totpoint (number of points)
+ 1 int: data_types (bit flags for what the stored data is)
- DATA (directly after header)
*totpoint times the data as specified in data_types flags
- simulation type
soft body = 0, particles = 1, cloth = 2
- data types (more can be added easily when needed)
data flag contains
----------------------------------------
index (1<<0) 1 int (index of current point)
location (1<<1) 3 float
velocity (1<<2) 3 float
rotation (1<<3) 4 float (quaternion)
avelocity (1<<4) 3 float (used for particles)
xconst (1<<4) 3 float (used for cloth)
size (1<<5) 1 float
times (1<<6) 3 float (birth, die & lifetime of particle)
boids (1<<7) 1 BoidData
Notes:
- Every frame is not nescessary since data is interpolated for the inbetween frames.
- For now every point is needed for every cached frame, the "index" data type is reserved for future usage.
- For loading external particle caches only "location" data is necessary, other needed values are determined from the given data.
- Non-dynamic data should be written into an info file if external usage is desired.
* Info file is named as normal cache files, but with frame number 0;
* "Non-dynamic" means data such as particle times.
* Written automatically when baking to disk so basically a library of particle simulations should be possible.
- Old disk cache format is supported for reading, so pre 2.5 files shouldn't break. However old style memory cache (added during 2.5 development) is not supported. To keep memory cached simulations convert the cache to disk cache before svn update and save the blend.
- External sb and cloth caches should be perfectly possible, but due to lack of testing these are not yet enabled in ui.
Other changes:
- Multiple point caches per dynamics system.
* In the future these will hopefully be nla editable etc, but for now things are simple and the current (selected) point cache is used.
* Changing the amount of cached points (for example particle count) is allowed, but might not give correct results if multiple caches are present.
- Generalization of point cache baking etc operator & rna code.
- Comb brushing particle hair didn't work smoothly.
* Fix crash entering particle mode, and particles not showing.
Janne, please check the changes I made in psys_cache_paths,
I'm not confident they are correct.
* Fix some warnings
