Easy Rigid Body – Documentation

Easy Rigid Body turns bones into rigid body physics with a few clicks. Select the bones, press one button, and the add-on builds one block per bone for you. It can create either:

• Physics – a dynamic chain of blocks linked by spring joints. Your bones follow the blocks, so hair, skirts, tails, ribbons, and cloth strips swing with gravity and inertia and are blocked by colliders.

• Collision – passive blocks that follow your animated bones (legs, torso, head…) and stop the Physics blocks from passing through the body.

Everything lives in one panel, and you never have to set up Blender's Rigid Body World, constraints, or collision layers by hand.

1. Requirements

• Blender 5.2.2 or newer

2. Installation

1. Open Blender 5.2.2 or newer.

2. Go to Edit > Preferences.

3. Navigate to the Add-ons tab.

4. Click the drop-down arrow in the top-right corner of the Preferences window and choose Install from Disk..., then find and select the addon package you downloaded. The file is typically named Easy Rigid Body.zip.

5. After installing, find "Easy Rigid Body" in the list and enable it by checking the box next to its name.

6. Once enabled, the addon panel will appear in the 3D Viewport's sidebar. You can access it by pressing the N key and looking for the Easy Rigid Body tab.

3. Quick Start

A. Hair / skirt / dress / tail / accessories / etc.

1. Select your armature and enter Pose Mode (Edit Mode also works).

2. Select the bones of the chains you want to simulate – for example, every bone of a skirt, strand by strand.

3. Set the mode to Physics and pick a shape (Box, Sphere, or Capsule).

4. Click Add Physics. A progress bar shows while the blocks, anchors, and joints are built.

5. Go to the Simulation Start frame and press Play. The bones now follow the blocks.

6. Tune the result with the sliders (see section 5).

B. Keep the physics out of the body

1. Select the bones of the body part to protect (thighs, shins, hips…).

2. Switch the mode to Collision and pick a shape. Capsule works well for legs.

3. Click Add Collision.

4. Play the animation. The Physics blocks are now stopped by the Collision blocks, which follow your animated bones exactly.

C. Finish

• Bake stores the simulation so playback is identical every time.

• Bake to Bones converts the result into normal bone keyframes. Use it before exporting FBX / VRM or moving to a game engine, because rigid body physics is not exported. If several Physics collections collide with each other (for example, hair and skirt on different groups), tick all of them in the Collections list and bake them in one go, so the collisions between them are kept (see section 5.9).

4. How It Works

One bone, one block. Every selected bone gets a block that is sized and aligned to it.

Rows. Selected bones are grouped into rows by their depth in the hierarchy: the top bone of each chain is row 1, its child is row 2, and so on. Inside a row, bones are sorted around the vertical axis through the armature origin, so neighbours to the left and right can be found. This is why the add-on works best with characters standing upright at the origin.

Physics mode:

• Every block is an active rigid body.

• Each block is joined to the block of its parent bone by a spring joint.

• The top block of every chain hangs from an invisible anchor attached to its parent bone, so the chain moves with your animation.

• Neighbouring blocks in the same row are linked sideways, limited by Max Side Gap, to keep skirts and hair panels together.

• Each bone receives a Copy Transforms constraint named RigidBody_Follow, which makes it follow its block.

Collision mode:

• Every block is a passive, animated rigid body parented to its bone.

• It blocks active rigid bodies and never drives any bone.

Collections: Each batch you generate goes into its own collection (Physics blocks default to RigidBody, Collision blocks to Collision). If the name is already used, .001, .002… is added. To give a collection your own name (e.g., Skirt or Leg Collision), rename it in the Collections list: double-click its name, or select it and click the Rename (pencil) button. Joints and anchors are hidden automatically but still take part in the simulation. Blocks are set up so they do not show up in final renders.

Per-collection settings: Each collection remembers its own values (shape scale, rigid body, and joint settings). Click a collection in the list and its values are loaded back into the panel.

Rigid Body World: It is created automatically when needed. When you add Physics, Substeps per Frame and Solver Iterations are raised to at least 20 if they are lower, and the playhead is moved to the Simulation Start frame.

5. Panel Reference

5.1 Top row

5.2 Generation settings

(Note: Controls that do not apply to the selected shape are greyed out.)

5.3 Add button and simulation range

5.4 Bake and display

5.5 Physics shape / Collision shape

Live scale sliders for the blocks of the active collection. Physics sliders only affect Physics blocks, Collision sliders only affect Collision blocks. The arrow button next to each title resets that group to 1.0.

Use the Collision sliders to make leg colliders a little bigger, or the Physics sliders to make skirt panels slimmer, without regenerating anything.

5.6 Rigid Body Physics

Friction, Bounciness, and Collision Margin apply to both Physics and Collision blocks of the collection. Blender multiplies the values of the two bodies that touch, so for a bouncy or grippy result set the Collision collection too.

5.7 Joint Physics

5.8 Wind

The Wind section is hidden by default. To show it, click the gear icon in the top row, tick Enable Wind and press OK. Unticking it hides the section again. Hiding only removes the controls from the panel: an existing wind object stays in the scene and keeps blowing. If you no longer want it, click the trash icon in the Wind section to remove the wind before you hide the section.

Click Add Wind to create a Wind force field whose strength is keyed over the simulation range. Once it exists the button becomes Update Wind: click it after changing any wind value. Updating keeps the wind object wherever you moved or rotated it. The trash icon removes the wind. The restore arrow resets the wind values.

5.9 Collections

The list shows the collections created by the add-on. Click one to make it active. Double-click a name to rename it.

6. Collision Layers (who hits whom)

Every collection has a Group number from 1 to 20. New Physics collections start at group 2, new Collision collections at group 1.

In the window, the cell of the group number is always lit. You can light additional numbers. The rule is simple:

Two collections that have at least one lit number in common never collide. Collections with no lit number in common collide normally.

Press OK to apply. The panel shows a progress bar while the settings are rebuilt. The window is read-only while a bake exists, so click Delete Bake first.

Examples:

• Default setup: Physics (group 2) hits Collision (group 1), because they share no lit number.

• Hair and skirt should not touch each other: leave both Physics collections on group 2 (they share a number, so they ignore each other).

• Hair and skirt should collide with each other: give them different groups, for example, 3 and 4.

• Hair should ignore the head collider: open Collision Layers for the hair collection and light the head collider's group number.

• Physics should only hit group 1: light layers 2 to 20.

Inside one Physics collection, neighbouring blocks are automatically prevented from colliding with each other. For very large setups the add-on limits the number of no-collision pairs; if some are skipped, a short message appears under the Collections list.

Pro (Cloth) Mode

Pro turns a Physics chain into a cloth-like net, and it is made for long skirts and other long, flowing fabric.

In normal Physics, neighbouring blocks in a row are held by a stiff limit. That works for hair, tails and other short pieces, but a long skirt needs to fold, drape and swing like real fabric. With Pro on:

• Soft side links: neighbouring blocks in a row are joined by a soft stretch spring, so they can fold against each other instead of staying locked side by side.
• Gentle return to shape: a weak pull brings the blocks back to their original shape, so the skirt settles naturally after moving.
• Diagonal links: extra links between rows resist shearing, so a long skirt does not twist or collapse into itself.

How to use

1. Tick Pro next to the Add Physics button, then click Add Physics. Untick it for normal Physics.
2. To change a collection that already exists, click its Pro button in the Collections list. Click again to turn Pro off.

Notes

• Pro only affects Physics. Collision blocks are not changed.
• If a bake already exists, click Delete Bake first so the change takes effect.

Easy Rigid Body – FAQ

General

What is Easy Rigid Body for?

It adds rigid body physics to bones with one click. Use Physics mode for hair, skirts, tails, ribbons, capes, and other hanging parts, and Collision mode for the legs, body, or head that those parts must not pass through. The add-on builds the blocks, joints, anchors, collision rules, and bone follow constraints for you.

Which Blender version do I need?

Blender 5.2.2 or newer.

Where do I find the panel?

In the 3D Viewport, press N and open the Easy Rigid Body tab.

Do I need to know Blender's Rigid Body system?

No. The Rigid Body World, constraints, and collision layers are set up automatically. Everything is controlled from one panel.

Does it work with any rig?

Yes, as long as it is an armature with bone chains, where each bone is a child of the previous one. It works with humanoid and non-humanoid rigs, and with any bone names.

Does it change my original bones or animation?

In Physics mode, a RigidBody_Follow (Copy Transforms) constraint is added to each simulated bone so that it follows its block. Your keyframes are not modified. Use Bake to Bones if you want ordinary keyframes instead of live physics.

Setting Up

I get the message "Select the armature and enter Pose Mode or Edit Mode…"

Select the armature object, switch to Pose Mode (or Edit Mode), and select the bones you want blocks for. Then click Add Physics or Add Collision.

Which bones should I select?

For Physics, select every bone of the chains you want to simulate. The top selected bone of each chain hangs from an invisible anchor attached to its parent bone, so that parent (for example a hip, spine, or head bone) keeps moving with your animation. Do not select it unless you want it simulated too. For Collision, select the bones of the body parts that should block the physics.

What do "Box", "Sphere", and "Capsule" mean?

They are the shape of the generated blocks.

• Box fits the bone length and the spacing to its left and right neighbours. Best for skirt panels, hair locks, and cloth strips.

• Capsule is round and runs along the bone. Best for long thin parts such as legs and arms.

• Sphere is round and can be stretched into an ellipsoid with Height Scale. Best for small round colliders.

Each block keeps the shape it was created with. Changing the shape later does not affect existing blocks.

Why do I see a warning that blocks use a plain cube?

The Box / Sphere / Capsule models are loaded from the asset/model folder (cube.blend, sphere.blend, capsule.blend). If that folder is missing or was moved, the blocks fall back to plain cubes. Put the folder back next to the add-on's init.py and generate again.

I get "N blocks could not be linked, check the bone hierarchy"

Physics mode joins each block to the block of its parent bone, so the chain needs a proper parent-child hierarchy. Make sure each bone is parented to the previous bone in the chain, then delete the collection and generate again.

Can I use several Physics collections (hair, skirt, tail)?

Yes. Select the bones of one part and click Add Physics, then do the same for the next part: every batch goes into its own collection. Rename each collection in the Collections list (for example Skirt, Hair) to tell them apart. Each collection keeps its own shape scale, rigid body, joint, and layer settings. Click a collection in the list to switch to it. When you export, you can bake several of them to bones in one pass (see Export and Baking below).

Does it work in Edit Mode?

Yes. Bones selected in Edit Mode or Pose Mode can both be used.

How do I rename a collection?

The name at the top of the panel is display only. Rename a collection in the Collections list: double-click its name, or select it and click the Rename (pencil) button.

Simulation

Nothing moves when I press Play.

• Go to the Simulation Start frame and press Play from there.

• Check that the current frame is inside the Simulation Start – End range.

• Make sure no bake exists. If one does, click Delete Bake; otherwise the old baked result keeps playing.

I changed a value but nothing changed.

The simulation is re-run automatically when you change a value, but a bake blocks that. Click Delete Bake first. Wind values are only applied when you click Add Wind / Update Wind. If the playhead is far from the start frame, go back to the start frame and press Play.

The skirt or hair is too floppy / too stiff.

• Too floppy: raise Spring Stiffness and Angular Damping, or lower Swing Limit.

• Too stiff: lower Spring Stiffness, raise Swing Limit, or raise Max Side Gap.

• Swings never calm down: raise Spring Damping and Angular Damping.

• Blocks fly off or move too freely: raise Linear Damping.

The simulation jitters.

Raise Linear Damping, Angular Damping, and Spring Damping. Also check that Collision blocks are not squeezing the Physics blocks: use the Collision shape sliders to make the colliders a little smaller, or lower Collision Margin.

The hair passes through the body.

• Create a Collision collection for the body parts (select their bones, switch to Collision, click Add Collision).

• Check Collision Layers. The two collections must have no lit number in common, otherwise they ignore each other. By default Physics is group 2 and Collision is group 1, which collide.

• Make the colliders bigger with the Collision shape sliders, or raise Collision Margin.

Hair and skirt pass through each other, or I want them to ignore each other.

Use Collision Layers (the layers icon next to the Collections list).

• Two collections with at least one lit number in common never collide. New Physics collections all start at group 2, so by default they ignore each other.

• To make them collide, give them different groups (for example 3 and 4).

• To make a collection ignore a collider, light the collider's group number in that collection's window.

Can I make the blocks bounce or grip more?

Use Bounciness and Friction. Blender multiplies the values of the two bodies that touch, so also raise them on the Collision collection to get a stronger effect.

How do I add wind?

The Wind section is hidden by default. Click the gear icon in the top row, tick Enable Wind and press OK. Then scroll to the Wind section, set Strength, Gust Frequency, Blow Time, Pause Time, Direction, and Seed, and click Add Wind. After changing any value click Update Wind. The wind object keeps the position and rotation you gave it. If the effect is too weak, raise Strength: heavier blocks and stiffer joints need more force (a 0.5 kg block weighs about 4.9 N).

I cannot find the Wind section.

It is hidden until you switch it on. Click the gear icon in the top row, tick Enable Wind and press OK.

I hid the Wind section but the wind is still blowing.

Hiding the section only removes the controls from the panel; the wind object stays in the scene. Show the Wind section again (gear icon > Enable Wind > OK) and click its trash icon to remove the wind.

Does the add-on change my Rigid Body World settings?

It creates the Rigid Body World if the scene has none. When you add Physics, it raises Substeps per Frame and Solver Iterations to at least 20 for stable joints, and it moves the playhead to the Simulation Start frame.

Editing and Cleaning Up

How do I resize the blocks after generating them?

Use the Physics shape and Collision shape sliders (Height, Width, Depth, or Radius for round shapes). They update live and the arrow button restores the original size. For Sphere and Capsule, moving Radius also scales Height by the same factor, while moving Height leaves Radius alone.

Can I hide the blocks?

Yes. Show/Hide hides or shows all blocks, and Textured / Wire changes how they are drawn. Hidden blocks still simulate. Joints and anchors are always hidden after generation.

Will the blocks appear in my render?

No. They are set up so they do not show up in final renders.

How do I remove physics from a few bones only?

In Pose Mode, select those bones and click the trash icon in the top row of the panel. It removes their blocks, joints, anchors, and Follow constraints, and leaves other bones untouched.

How do I remove a whole collection?

Select it in the Collections list and click the minus button. It deletes all blocks, joints, and anchors and removes the Follow constraints from the bones. There is no confirmation, but Ctrl+Z undoes it.

Can I delete the generated objects by hand?

It is better not to. Use the add-on's delete buttons: they also clean up the joints, anchors, and bone constraints that are linked to those objects.

How do I restore the default values?

Each section has a small restore arrow. The refresh icon in the top row restores every number in the panel.

Export and Baking

What is the difference between Bake and Bake to Bones?

• Bake stores the rigid body simulation in Blender's cache so playback is identical every time. The blocks and joints stay in the scene.

• Bake to Bones writes the result into normal bone keyframes (one key per frame from Simulation Start to End) and then removes the baked Physics collections' blocks, joints, anchors, and Follow constraints. Collision collections are kept; delete them yourself in the Collections list if you no longer need them.

How do I export to FBX / VRM / a game engine?

Rigid body physics is not exported, so click Bake to Bones first. Your bones then carry plain keyframes that any exporter and game engine understand.

Can I bake several Physics collections to bones at the same time?

Yes. In the Collections list, tick the box on the right of every Physics collection you want to bake, then click Bake to Bones once. The button shows how many collections are ticked, for example Bake to Bones (3). All ticked collections are sampled in the same pass and their bones get keyframes together. When nothing is ticked, Bake to Bones bakes the active collection only. When something is ticked, only the ticked collections are baked, so tick the active one as well if you want it included.

Why should I bake colliding collections together instead of one by one?

Bake to Bones removes the blocks of the collection it bakes. If you bake hair first, its blocks are gone when the skirt is sampled, so the skirt can no longer collide with the hair and that effect is lost in the result. Ticking both and baking once keeps the blocks of both collections in the simulation while the keyframes are recorded, so the collisions between them are kept. Remember that two Physics collections only collide with each other if they have no lit number in common (see Collision Layers), for example groups 3 and 4.

A Physics collection I did not tick is still in the scene after Bake to Bones.

That is intended. Only the ticked collections are baked and removed. The collections you left unticked stay in the scene and keep simulating, but they can no longer collide with the blocks that were removed. If they collide with each other, tick all of them.

Bake to Bones is greyed out or does nothing.

• It only works on Physics collections. Select a Physics collection in the Collections list, or tick the boxes of one or more Physics collections. It is greyed out when the active collection is a Collision collection and no box is ticked.

• Stop animation playback before clicking it.

• A ticked collection that no bone follows is skipped, and a message tells you which one. If none of the ticked collections has a bone following it, nothing is baked.

Can I change the Collision Layers while a bake exists?

No. The window is read-only while a bake exists. Click Delete Bake, change the layers, then bake again.

Troubleshooting

A message under the Collections list says "block pairs skipped"

This is a safety limit (8000 pairs) for very large scenes. Some blocks that should ignore each other may still collide, so try reducing the number of bones or blocks.

The panel is missing.

Check that the add-on is enabled in Edit > Preferences > Add-ons, that you are in the 3D Viewport, and that the sidebar is open (N).

Something went wrong while generating.

Press Ctrl+Z to go back, check that the armature is active and in Pose Mode with bones selected, and try again. If the problem persists, please contact the seller with your Blender version and a short description of the bones you selected.