rayman

Why would they? Sop solvers are just wrapped dops. Removing them means that they have to rewrite the whole fx context inside sops for the purpose of not having dops or just removing the access to them which equals hcore. Both approaches are very counter intuitive - every TD wants to have access to the solver and the ability to modify it.

This one already exists - it is called Houdini CORE.

For a Muscle to Bone use 'Attatch To Geometry' Vellum Constraint with predefined groups. For Muscle To Muscle - 'Glue'.

Vellum constraints are using default points from the vellum object in order to describe themselves to the solver. Check the vellum constraint node : no matter how many constraints are created, point count is the same - there are only new primitives created. Connect Adjacent Pieces on the other hand may or may not change the point count depending of the type of connection. From the three methods only Adjacent Points could be used with Vellum.

Make sure that geometry can be interpolated - just put a TimeBlend SOP + PointVelocitySOP before the source and turn on Velocity Blur option on VolumeRasterizeAttribute SOP, add some more Blur Samples and you are ready to go - no need to trail it or use more solving substeps. Edit : Just realized you are using the old fluid source - there should be alternative Velocity Blur option , but keep in mind that it is SLOW.

Yeah, thats because vdbs and houdini native volumes are using reversed sdfs. Velocities are just fine.

It looks like it, but it is not - if you simulate only the smoke, you will see the exact same behavior. I guess it is some kind of computational error or just the pressure solve doing its own thing. Edit : it is an error caused by the advection method.

You can generate collision / collisionvel fields from the vellum and copy it back to the smoke solver. DOP_Vellum_Pyro_Feedback_RnD_v002.hipnc

This does not seem right. Most of the time forces are distributed pretty uneven based on the stress of the constraint system. I modified your scene a bit, to illustrate my point - as you can see all constrains are using the same break threshold (with the exception of both sides - I made them stronger on purpose, as they are most likely to fail), but only some of them are broken - where the forces are much stronger than the rest of the constraint network. You can expand on this and add different types of constraint breaks based on force, torque or distance between the pieces. Snap_Constraints_Example_2_MOD.hipnc

I think, you have to repack the pieces before the sim using repack fragments option, but I've never found the solution to the other problem which is the huge collision padding between the packed objects and the vellum.

attribute wrangle in details mode: int prim = 1; int pts[] = primpoints(0,prim); setprimvertex(0,prim,0,pts[1]); setprimvertex(0,prim,1,pts[0]);

This is actually the expected behaviour. Using glue constraints will make the solver treat all connected pieces as one object (no relative movement between them) until the constraints are broken. To break a glue you need to apply collision (impact) force to the corresponding piece - forces/constraints can not force a glue to break. In this case it is like constraining a single active piece between 2 animated objects - hard constraints will stretch no matter of what. The only reason the glues are broken in your example is because of some instabilities of the collisions between the connected pieces and the initially detached pieces. If you want to force the object to break in the points with the bigger stress, then use only hard constraints and break them manually using the 'force' attribute.

You can add single Gas Field Wrangle into the velocity update plug and try something like this: float minrad = 1; float maxrad = 1.5; float velmult = 1.0; vector center = set(0,0,0); vector dir = center-v@P; float dist = length(dir); float mult = fit(dist,minrad,maxrad,0,1)*velmult; v@vel += normalize(dir)*mult;

You can add empty data to the object you want to emit in, name that data , then add enable solver after the sop solver and type the same name to the Enable Data parameter.

WOOO HOOOO!! HAPPY B-DAY!!!