kleer001

Vellum reads SOP point attributes once at sim init, then runs entirely in DOP space with no link back to the source SOP. Animated Cd, animated stiffness masks, time-varying pin weights — all silently dropped from frame 2 onward. The standard fixes (hand-rolled popwrangle microsolver, separate cache + Geometry Wrangle DOP, learning that microsolvers don’t run on the creation frame) are nontrivial plumbing.

This HDA is that plumbing in one click. Same popwrangle-in-Pre-Solve pattern SideFX uses internally for muscleupdatevellum.

What it does: - This DOP HDA inserts a popwrangle microsolver into the Vellum Solver’s popsolver Pre-Solve chain — fires every substep, copies listed point attributes from the upstream SOP onto the live sim points - SOP-level init wrangle seeds frame 1 (microsolvers skip the creation frame in Houdini) - Channel-referenced parms keep the SOP wrangle and DOP streamer in sync — edit one, both update

Setup: select Vellum Solver, File > Run Script..., pick the .cmd. Three files (.cmd, .py, .hda) sit in one folder. No shelf install, no copying into prefs, no restart.

Supported attribute types: float scalar/vec3/vec4 and integer scalar. Match by id (topology-safe) or ptnum.

Free download: https://kleer001.github.io/funkworks/vellum_attr_stream [kleer001.github.io]

Houdini 19.5+, any edition.

FX users: a build script is included to compile the HDA clean under your own license.

🐜 More free tools at https://github.com/kleer001/funkworks [github.com]

Getting a zoom blur or spin blur in a COP network means writing the same wrangle: work out the aspect-corrected @P coordinate space, build the radial sampling loop, use volumesamplep so alpha doesn’t drop. It’s 30 lines of boilerplate for a basic result.

Zoom / Radial Blur COP is that node. Connect an image, pick a mode, done.

Blur modes: Zoom Blur (radial scale streaks from center) or Radial Blur (spin/arc smear at constant radius)
Center control: Screen Space (−1..1, 0 = image center) or Pixels (absolute coordinates, Y=0 at bottom-left)
Samples: 1–256, slider with strict minimum — raise for finals, lower for layout speed

Both modes share the same center controls. Switching modes hides the irrelevant parameter (Blur Pixels vs. Blur Angle). Alpha is preserved throughout via volumesamplep.

docs and download: https://kleer001.github.io/funkworks/zoom_blur_cop [kleer001.github.io]

Houdini 20.5+, any edition.
FX users: a build script is included to compile the HDA clean under your own license.

🐜 More free tools at FunkWorks Home [kleer001.github.io].

Houdini's built-in Resample COP only does Stretch. If you want a letterboxed fit, a fill that crops to the canvas edge, or a tiled repeat with mirroring, you're chaining nodes and computing UV offsets by hand — and redoing that math every time a resolution changes. If you want to resize by a reference image's resolution you need to add another node to the mix.

Scale COP is a free HDA that wraps the whole thing in one node. Pick a target resolution, choose a fit mode, optionally tile, pick a filter. Done. No manual offset math.

Fit modes: Distort, Fit (letterbox), Fill (crop to fill), Width, Height, None (1:1 pixel)
Tile modes: None, Repeat, Mirror X, Mirror Y, Mirror Both (with UV offset)
Filters: Point, Bilinear, Box, Bartlett, Catmull-Rom, Mitchell, B-Spline, Auto
Size reference input: connect any upstream node to drive the output resolution automatically — no manual width/height entry when your canvas size changes

Free download: https://github.com/kleer001/funkworks/releases/tag/scale_cop-v0.1.99 [github.com]

Houdini 20+, any edition. FX users: a build script is included so you can compile the HDA under your own license and avoid the Indie/Apprentice flag.

First Houdini release from Funkworks — a small open-source collection of free DCC tools built from real workflow problems. Feedback and bug reports welcome.

🐜 More free tools at https://github.com/kleer001/funkworks [github.com]