Houdini-and-Chill

“` How to deal with Iterations: Substeps – More expensive, but gives a better solve – especially for higher stiffness values Constraint Iterations – Increase for higher stiffness value to control excessive deformations – great for cheaper solver at high resolutions Smoothing Iterations –  smoothing ops, to smooth out errors of excessive deformations, or constraint errors Collision Iterations – Uses the Detangle sop – lower frequency iterations – complicated and time consuming – increase when collisions are fighting against constraints or other collisions However, its probably better to increase substeps and decrease constraint iterations for a more accurate solve – and to reduce load on the constraints – but is more expensive “`

From @trzanko ray sop or prim uv’s don’t yield super great accuracy, as it only interpolates among a primitive’s points, to get a smooth position you can leverage the osd vex functions
here’s my subdiv ray snippet which illustrates this, you can see the diff between the osd pos and the primuv pos if you comment out the line which declares the variable sDP
“`int primNum; vector UV;
float dist = xyzdist( 1, @P, primNum, UV);
vector restN = primuv(1,”N”,primNum,UV); vector posOnRest = primuv(1,”P”,primNum,UV);
//subdiv float pU, pV; int pId; int patch = osd_lookuppatch( 1, primNum, UV.x, UV.y, pId, pU, pV);
//these two functions return the last argument //so posOnRest is being overwritten in the function, much like xyzdist() int sDN = osd_limitsurface( 1, ‘N’, pId, pU, pV, restN); int sDP = osd_limitsurface( 1, ‘P’, pId, pU, pV, posOnRest);
@P = posOnRest;“`

posting Tighe’s post for re-gemming

forums.odforce.net/topic/31435-smoke-solver-tips-and-tricks/

eat jay’s delicious brains there

i mean learn from jay there