Rigid Body Simulation in Blender: Setting Up Active and Passive Objects

What will you learn in this guide?

Blender’s rigid body system simulates the movement of solid objects. It affects their position and orientation but does not deform their shape. This makes it useful for controlling the movement of solid parts in a scene. The system works with animation: rigid bodies can be part of parent-child relationships, animation constraints, and drivers, just like regular objects.

In this guide, we cover adding rigid body objects to a scene, distinguishing between active and passive types, checking the simulation world’s collection, and baking the result. Some interface option names are left in English, as they appear in the source documentation.

Requirements

You need a scene containing mesh objects in Blender. The source documentation does not specify a particular Blender version number or account requirement, so no version or account requirement is given here. For the simulation to work, rigid body physics must be added to the objects, and they must be in the collection selected in the scene’s Rigid Body World settings.

Rigid bodies fall into two basic types:

• Active: Simulated dynamically.

• Passive: Remain fixed.

Both types can be driven by the animation system when Animated is enabled. During simulation, the system controls the position and orientation of dynamic rigid bodies. Because the object’s location and rotation values are not changed directly, this behavior is similar to a constraint.

Basic setup, step by step

1. Prepare the mesh objects. Make sure the objects that will participate in the simulation are meshes. Only mesh objects can be included in Blender’s rigid body simulation; other objects in the scene are not automatically treated as simulation elements.

2. Add rigid body physics. After selecting an object, use the Rigid Body button in the Physics tab under Properties, or choose Add Active or Add Passive from the Object > Rigid Body menu. Select Active for an object you want to be calculated dynamically, and Passive for one that should remain fixed.

3. Check which objects will participate in the simulation. When rigid body physics is added to an object, a group named RigidBodyWorld by default is created, and the object is added to it. You can create multiple Rigid Body World collections in a scene and distribute objects among them. However, objects and constraints participate in the simulation only if they are in the collection specified in the Collection field of the Rigid Body World panel. Check this assignment if you get unexpected results.

4. Review the world settings. The Scene > Rigid Body World panel provides shared settings for the rigid bodies in the simulation. Speed can be used to speed up or slow down the simulation. Substeps Per Frame sets the number of simulation steps taken per frame. The source documentation gives conflicting information about this setting: one explanation says higher values produce more accurate and slower results, while another says the setting affects accuracy only, not speed. So do not assume that increasing Substeps Per Frame will definitely increase computation time. Solver Iterations sets how many iterations the constraint solver performs at each simulation step; higher values improve accuracy and the stability of constraints and object stacks, while producing slower results.

5. Consider Split Impulse if needed. This setting enables or disables the reduction of excessive velocity that can occur during collisions. It can produce smoother results by limiting the force that separates colliding objects, but may reduce simulation stability, especially when many objects are stacked. So consider it a setting to use based on observed results, rather than an improvement that should be enabled in every scene.

6. Set the frame range and cache. In Scene > Rigid Body World > Cache, you can set the first and last frames for which the simulation will be active. Bake calculates the simulation and preserves the cache; you must be in Object Mode to do this. After baking, you can clear the cache with Delete Bake. The panel also includes other operations, such as calculating up to the current frame and baking from the cache.

7. Save the file and check the result. The Blender documentation states that if the file has not been saved, the cache may be created in memory and may be lost if the file is not saved. So save the file before baking. Also check the simulation’s start and end frames; if needed, use the options to calculate up to the current frame or bake all dynamics.

Common issues

The object does not move: First, confirm that the object is a mesh and that rigid body physics has been added. Then check whether it is Active or Passive. A Passive object remains fixed; an object expected to move dynamically may have been set to this type by mistake.

An object does not appear in the simulation: Check the Collection field in the Rigid Body World panel and confirm that the object is in that collection. The same collection membership rule applies to constraints.

The cache disappears: Make sure the file has been saved before baking and that you are in Object Mode when you bake. The cache may be kept in memory if the blend file has not been saved.

Stacks are unstable or the result is unexpected: Review Solver Iterations and Substeps Per Frame in light of your goals. According to the documentation, increasing Solver Iterations can improve accuracy and the stability of constraints and stacks, but may produce slower results. The documentation is contradictory about the effect of Substeps Per Frame on speed, so do not make definitive assumptions about performance. Keep in mind that Split Impulse can also reduce stability, particularly in stacks.

The object’s transform is unexpected: During simulation, the rigid body system controls the position and orientation of dynamic objects; it does not directly change the object’s location and rotation values. If you need to apply transforms, you can use Blender’s Apply Object Transform operation. Scale also affects the simulation, but is controlled by the animation system.

Use in architectural and visualization workflows

In architectural visualization and interior design work, rigid body simulation can be useful for teams that want to experiment with the movement of solid objects in a scene as part of an animation workflow. The Active and Passive distinction lets you decide which elements are calculated dynamically and which remain fixed. The source documentation does not specify hardware requirements, render time, or licensing conditions, so no additional technical claims can be made about these topics.

Before sharing or delivering a project, check the collection assignments of the objects that should participate in the simulation, the frame range, and the bake status. In scenes with many stacked objects, consider that Split Impulse may affect stability. For Substeps Per Frame, keep the contradictory speed information in the documentation in mind and test its effect on the scene.

Next steps

After the initial setup, review the Active and Passive roles and confirm that the simulation includes the necessary objects. Set the frame range, save the file, and then bake in Object Mode. For more complex setups, Blender’s Rigid Body menu also includes operations for adding and removing objects and constraints, and editing their properties. External force effectors can affect rigid body simulations, but the source documentation does not provide setup steps for any specific effector type or setting, so no specific instructions are included here.

Source and license

This guide has been adapted into Turkish based on Blender’s introductory rigid body simulation and Rigid Body World documentation. Both sources are published under the CC BY-SA 4.0 license.