Objects pass through each other
Check sensor flags, both collision masks and shared negative group indices.
World & physics
Physics Bodies & Collision Groups
Tune the body behind an object, use a simpler collider where appropriate, and configure collision, render and joint groups separately.
Creator guide
What you can build
Tune the body behind an object, use a simpler collider where appropriate, and configure collision, render and joint groups separately.
The options below are grouped by the way you use them. Available controls depend on the selected object, editor mode and enabled features.
Creator guide
Options and behavior
Find the control you need, then follow the setup steps to test it in a level.
Body configuration
| Option | What it does |
|---|---|
| Body Type | Dynamic bodies respond to forces, static bodies stay fixed and kinematic bodies follow configured movement without the same force response as dynamic bodies. |
| Density / Friction / Restitution | Tune mass per area, contact grip and bounce. |
| Linear Damping / Angular Damping | Reduce linear or rotational motion over time. |
| Gravity Scale | Scale the gravity response of the object. |
| Inertia Scale / Disable Rotation | Tune resistance to rotation or lock rotation when the gameplay requires it. |
| Start Velocity X / Start Velocity Y / Start Angular Velocity | Set the initial horizontal, vertical and rotational motion. |
| Use Simple Physics Body / Simple Physics Body Type | Replace the detailed collider with the supported simple shape. Check the collider rather than assuming it matches every visual detail. |
| Body Width / Body Height / Body Radius | Set the dimensions used by the selected simple body type. |
| Is Sensor | Detect contacts without acting as a solid obstacle. |
Collision and rendering
| Option | What it does |
|---|---|
| Collision Group / Collide With | Choose the object's collision category and the categories it accepts. Both objects' filters matter. |
| Collision Group Index | Matching non-zero indices override category filtering: positive indices force contact, negative indices suppress contact. |
| Override Render Layer Group / Render Layer Group | Choose a render-order group independently of the collision category. |
| Joint Connection Group / Joint Connects To Groups | Configure which groups are eligible for physical joint connections independently of render order. |
| Allow Joint Connection From Different Collision Group | Permit supported connections across collision categories. |
| Debug Draw | Inspect the actual collision shapes in the level before changing the artwork to solve a physics issue. |
Creator guide
Try it in a level
Start with a small scene so each setting has a visible result.
- Choose the body type and tune density, friction and bounce on a simple test scene.
- Enable a simple collider only when its shape suits the object.
- Configure both sides of collision filtering and inspect any non-zero group indices.
- Use the render override for visual order and joint groups for connection rules, then test in play mode.
Creator guide
If the result looks wrong
Use the symptom to find the next setting to check.
An object looks correct but catches on corners
Use Debug Draw to inspect its actual body. Tune the simple-body dimensions if it uses a simplified collider.
Changing render order breaks contacts
Use Override Render Layer Group instead of changing the collision category solely for visual ordering.