Make Piles of "ANYTHING!" With Houdini

Use a rigid-body simulation to arrange a pile, then keep a single settled frame as the model. This lesson demonstrates that process with coins: build one source object, distribute and rotate copies in a volume, let them fall onto a floor, and export the selected arrangement. The simulation is a modeling aid, so the useful output is the chosen pile rather than necessarily the entire animation.

The recorded Houdini workflow uses historical Copy Stamp and shelf-created RBD nodes. Its precise version is unverified. The title’s “anything” describes the idea’s flexibility; only the coin example is demonstrated, and different shapes would need their own collision and settling checks.

Make one coin before distributing it

At 00:34, create the coin geometry from a capped polygon Tube. The example reduces its height to 0.1 and uses 24 columns for a rounder silhouette. Select the end caps for PolyExtrude, inset them, then use a second extrusion to recess the selected region. These operations establish the rim and face of the coin before multiplication makes geometry changes expensive to inspect.

A Font containing a dollar sign supplies the face detail. Extrude it with a back surface, rotate it negative 90 degrees and adjust its height so that it intersects the coin shallowly. The first Boolean trials leave unwanted floating pieces. The instructor changes the placement, makes a copy scaled by negative one on Y for the opposite side, and revisits the Boolean operation. An Intersect trial is accepted near 05:00 after subtraction does not give the desired result.

The captions do not establish every final Boolean input and operation well enough to prescribe a complete node recipe. Follow the visible geometry at this point: the intended result is one coin with shallow detail on both faces, without detached fragments. Do not carry obvious floating pieces into hundreds of copies. Gold materials and rendering are not developed in the narrated workflow.

Scatter inside a volume and vary the copies

At 05:36, create an elevated polygon Sphere to define the initial cloud of coins. IsoOffset turns it into the fog-like volume used for scattering. Scatter supplies points throughout that region; Copy to Points places the coin geometry onto those points. A Transform on the source reduces its size to suit the distribution.

The demonstration then replaces Copy to Points with Copy Stamp to introduce rotation variation. A named stamp variable derives a random value from the template point number and remaps it into a zero-to-360-degree range. An upstream rotation parameter reads that variable from the copy node, with zero as its fallback.

Several errors matter here. The variable name must match between its definition and lookup. The copy-node path must be valid, including the node’s numeric suffix. Fixing those text errors clears a warning but still does not produce variation: Stamp Inputs also has to be enabled. At 09:01, enabling it finally makes the differing orientations visible.

This source teaches the historical stamping relationship, but its automatic captions do not preserve a dependable executable expression. Inspect the on-screen fields if reproducing that exact setup. The separate Copy to Points instead of Copy Stamp lesson explains a different copying workflow; it does not certify a drop-in replacement for every node in this recording.

Simulate the fall and tune the contacts

At 09:45, use the rigid-body shelf workflow to make the distributed coins an RBD Packed Object. The narration briefly names a different shelf option before settling on the packed-object choice. The tool creates the simulation network and supporting geometry nodes.

The first point count is too costly, so the Scatter count is reduced, with 200 coins accepted for the example. Play the simulation to inspect the falling arrangement. When the coins continue downward without landing, add a Ground Plane from the collision tools. The floor can remain hidden in the viewport while still providing collisions.

At 12:00, the pile has considerable residual motion. In the coins’ physical settings, increase friction and reduce bounce to 0.1. Set the ground’s bounce to 0.1 as well; the narration leaves its friction at 1. Restart from the beginning after these changes. An already calculated frame is not a new test of revised physical settings.

Judge whether coins stop bouncing and sliding into an acceptable arrangement. The demonstration improves but still needs a long settling period. The recorded settings are useful comparison points, not a guarantee that all coin proportions or other shapes will settle in the same number of frames.

Change the starting arrangement when the pile is unattractive

At 14:02, some coins balance in an unwanted pattern. Change Scatter’s global seed and recalculate to obtain a different initial distribution and resulting pile. This changes where objects begin, rather than manually moving the final coins one by one.

The instructor also lowers the distribution sphere to shorten the drop. That reduces the fall available before impact and can produce a less energetic start in this setup. Keep this separate from contact adjustments: friction and bounce affect interactions, while source height and seed alter the initial conditions.

Some coins still roll away, and the chosen simulation does not settle until near the end. Pick the arrangement by inspecting its silhouette, contact relationships and stray pieces. A stationary-looking frame may be useful for a still asset even when the recording does not establish a fully motionless equilibrium.

Hold the chosen frame and test the export

At 15:20, append a TimeShift after the rigid-body result. Remove the animated frame channel so the node holds a fixed frame; the example keeps frame 240. Playing the timeline should now leave the selected pile unchanged at that output. This is a frame selection, not a demonstration of a reusable disk-cache pipeline.

Export the result as FBX, hide the original scene object and create a new geometry object to test it. At 17:00, a File node reads the exported FBX and the coin pile reappears. That readback is the lesson’s final delivery check: the exported file contains the arrangement rather than merely depending on the visible simulation object.

The source does not inspect materials, polygon budgets, collision proxies or behavior in a game engine. Its confirmed endpoint is a locally reimported static pile. For this workflow, keep three checks distinct: the source coin has clean intended detail, the simulation produces an arrangement worth keeping, and the exported geometry reproduces that selected arrangement.