Rigid Body Simulation in Blender 5.2: Objects That Fall, Collide, and Stack
Making a tower of blocks collapse believably, with each piece falling, bouncing, and stacking differently, is nearly impossible to animate by hand. Blender 5.2's rigid body simulation calculates that physics for you: this guide walks the full workflow, from Active/Passive and collision shapes to baking keyframes and rendering.
What Rigid Body Simulation Is and When to Use It
Solid Objects That Obey Physics: Gravity, Impacts, and Stacking
Rigid body is Blender's system for solid objects: once you mark them as rigid bodies, gravity pulls them down, they collide, bounce according to their material, and stack up without you moving a single keyframe. The Bullet engine does the work underneath, the same kind of physics video games use, and it is perfect for collapses, swinging chains, machinery breaking apart, or simple objects falling onto a table.
What Rigid Body Is Not: Cloth, Fluids, Hair, and the New Node-Based Physics
It helps to set boundaries: rigid body only simulates solid, non-deforming objects. A cloth that folds, a liquid that splashes, or hair that sways is not rigid body, and in Blender 5.2 that soft category now lives elsewhere, in node-based physics with XPBD solvers inside Geometry Nodes. If your object is a solid that does not deform, the classic workflow in this guide is the right one.
What Blender 5.2 LTS Brings to Physics
Blender 5.2 LTS, released on July 14, 2026, with support through mid-2028, is the production-recommended version. In it, classic rigid body is configured exactly where it always was: in the object's Physics tab and in the Rigid Body World under Scene Properties. The physics news lives in hair and cloth, so if you are coming from older versions, your rigid body knowledge carries over unchanged.
Active vs Passive: The First Switch
Active: The Objects the Simulation Moves
Everything starts in the Physics tab: select an object, add Rigid Body, and pick its type. An Active body is one the simulation moves: it falls, collides, bounces, and stacks. The blocks in the classic tower example are all Active, because you want each piece to react independently.
Passive: Floors, Walls, and Fixed Objects That Only Receive Collisions
The floor and walls are marked Passive: physics treats them as solid obstacles that receive collisions but never move or fall. That is a huge saving, because a Passive body does not need to solve its own motion, only to serve as a collision surface. Think of Passive objects as the set dressing and Active ones as the actors.
Dynamic vs Kinematic: When an Animated Object Must Push Others
Active bodies also have a mode. Dynamic is the default: physics controls everything. Kinematic is the trick for objects with their own animation: the simulation does not move a Kinematic body, but it pushes Dynamic ones as it passes through them. That is what you use for a sphere that knocks down the tower or a wall that slides away: animate it by hand with keyframes, keep it Kinematic while it pushes, and switch it to Dynamic once the motion ends if you want it to react to what it knocked over.
Collision Shapes: The Decision That Makes or Breaks Your Simulation
Why Not Always Use Mesh: Performance and Errors
The collision shape defines how the engine sees the object's form. The Mesh option uses the exact mesh, and it is tempting because it promises total precision, but it is the most expensive and the most error-prone: with a part made of a hundred thousand polygons, every contact is computed against all that geometry and the simulation turns slow and unstable. The practical rule is to start with the simplest approximation that looks right.
Convex Hull, Box, Sphere, Capsule, Cylinder, and Cone
Blender offers several approximations. Convex Hull wraps the object like a shell with no holes, ideal for organic parts or medium meshes. Box, Sphere, Capsule, Cylinder, and Cone are primitives that compute instantly and cover most mechanical parts: a brick is a Box, a ball is a Sphere, a chain link is approximated with a Convex Hull torus or a Capsule depending on its shape.
Typical Cases: Which Shape to Pick for Each Part
For the tower blocks, one Box per block. For the striking sphere, a Sphere. For parts with real cavities that must catch each other, like chain links, Convex Hull usually gives the best balance of speed and stability, and you only fall back to Mesh when no approximation reproduces the behavior you need.
The Rigid Body World and Its Settings
Scene Properties: The Physics World, Gravity, and Units
With objects marked, you enable the Rigid Body World in Scene Properties. That is where the global physics stage lives: gravity, which by default replicates Earth's, and the solver's precision settings. If your scene uses very large or very small units, check the scale too, because a simulation designed in meters fails when your object measures millimeters.
Substeps per Frame and Solver Iterations: From the Default 10 to Stability
Two settings concentrate 90 percent of physics problems. Substeps per Frame divides each frame into finer calculation steps, and Solver Iterations decides how many times the solver corrects contacts in each step. Both come in at around 10 by default, and when you see objects tunneling through each other or stacks jittering for no reason, the answer is almost always to raise them toward 20 or 30. It costs more calculation time, but it turns a shaky block pile into a tower that settles calmly.
Friction and Bounciness in Physics Materials
The final feel comes from physics materials, created from the Physics panel. Friction controls how much objects slide against each other, and Bounciness how much they bounce. For wood or stone blocks, friction around 0.6 with low bounciness gives stable stacking; raise the bounce only for balls or rubber parts.
Your First Simulation: The Collapsing Tower
Setting Up the Scene: Passive Floor, Active Blocks, a Striking Sphere
Let us build the full example. Create a plane as a Passive floor, stack about ten Active blocks with a Box collision shape, and line up a sphere in front of the tower. Animate the sphere for a few frames so it advances toward the base, mark it Kinematic while it pushes, and switch it to Dynamic at the impact frame. Press play: the sphere knocks down the blocks, and every piece falls, collides with the floor and the others, and ends in a different pile every time you change something.
Playing and Observing: Objects That Tunnel or Jitter
The first playback is rarely perfect. The classic symptoms are two: objects tunneling at high speed, because the solver did not have enough steps to detect the impact, and stacks that jitter or jump, because the iterations cannot stabilize so many simultaneous contacts. Both are fixed in the Rigid Body World, not by moving objects by hand.
Tuning Shapes, Substeps, and Solver Until It Is Stable
Raise substeps per frame toward 20 or 30, raise solver iterations in the same direction, and drop each part's collision shape to the simplest possible primitive. Play and repeat: rigid body simulation is deterministic with the same settings, so you see the effect of every change immediately at the same point on the timeline.
Constraints: Joints Between Rigid Bodies
Fixed, Point, Hinge, Slider, Piston, Generic, Generic Spring, and Motor
When two bodies must move connected, rigid body constraints come in. Fixed welds two objects as if they were one. Point joins them at a pivot that can rotate freely. Hinge creates a pivot that rotates on one axis. Slider forces motion along a straight line, and Piston combines sliding with rotation. Generic and Generic Spring let you combine axes with or without elasticity, and Motor applies continuous rotation to a body.
The Hinge Example: A Door or Lid with a Hinge Constraint
The clearest example is a door: connect a Passive frame to an Active door leaf with a Hinge constraint and, when you play, the leaf rotates around the hinge axis and swings like a real door. The same pattern works for chest lids, clamps, or any articulated part.
Motor and the Axis-Alignment Warning (the Wheel Case)
The Motor is the classic beginner trap: it applies rotation, but it uses a different axis convention than the Hinge, and if the objects' local axes are not aligned, instead of a spinning wheel you get confusing perturbations. The safe recipe for a wheel is a Hinge as the real pivot plus a Motor as the drive, checking that both point along the same rotation axis.
From Calculation to Result: Baking to Keyframes
Why Bake: Repeatable, Editable, and No Surprise Recalculations
While the simulation lives as a calculation, it is fragile: any unrelated change, moving an object, or opening the file on another machine can recalculate it differently. Baking to keyframes freezes the result: it turns the simulation into a normal keyframed animation, reproducible on any machine and editable like any other animation.
How to Bake the Rigid Body and What It Produces
In the Rigid Body World panel you use the bake button (Bake All Dynamics): Blender plays the simulation and writes the location and rotation keyframes of every active body. From that point you can tweak the result by hand, trim the animation, or delete the physics entirely without anything recalculating.
Rendering or Exporting the Final Animation
With the bake done, you render with total peace of mind: Render Animation produces the sequence and no frame will come out different because the solver changed its mind mid-render. The same principle applies if you export the scene to another program: what you export is fixed animation, not a pending calculation.
Rigid Body and Blender 5.2's Node-Based Physics
What Changed in 5.2: Hair and Cloth with XPBD in Geometry Nodes
Blender 5.2 moved hair and cloth simulation to a node-based system: the XPBD Solver inside Geometry Nodes, with built-in node groups, replaces the classic modifier workflow for that kind of material. It is a major paradigm change for soft matter, and it is worth knowing because physics searches in Blender now lead to both worlds.
Why Classic Rigid Body Remains the Path for Solids
For rigid solids, nothing changed: the classic rigid body workflow with Active/Passive, collision shapes, Rigid Body World, and constraints is still the standard path in 5.2. You do not need nodes to make a tower collapse; you need well-marked bodies, efficient shapes, and a baked result.
Conclusion
Rigid body simulation turns what is impossible to animate by hand into a minutes-long workflow: mark Active and Passive, pick lightweight collision shapes, tune substeps and solver when something jitters, connect parts with constraints for hinges and motors, and bake to keyframes before rendering. It is free, it ships with Blender 5.2 LTS, and it is the natural first step into procedural physics. If you keep one tip: when a simulation fails, do not move objects by hand, raise the Rigid Body World's precision and simplify the shapes.
