Build along / Example 03
Make sparks on impact
Save a short spark burst and trigger it when a physical object hits the floor.
- Metal Sparks
- Particle Settings
- Contact
A small project with a visible result
What you will build
A falling object produces a brief spark effect when it hits a solid platform.
Before you start
A simple test level with a static floor and a dynamic object above it. The two objects must be allowed to collide.
| Control | Start with | Why |
|---|---|---|
| Particle preset / saved name | Metal Sparks / Impact Sparks | Keep the preset’s graphics and motion for the first pass. |
| Pattern | Impulses | A limited emission burst for an impact. |
| Repeat impulses / Impulse count | Off / 1 | One impulse each time the effect is played. |
| Particle Effect | Impact Sparks | Select the saved effect on the falling object. |
| Play Particles When Created | Off | Make the first test isolate collision playback. |
| Play Particles On Contact | On | Enable the collision event. |
| Play Particles Scale / Enable Contact Force | 1 / Off | Start with a fixed effect size before adding force scaling. |
| Rotate Particle Toward Contact Normal | On | Orient the burst to the collision direction; inspect its rotation. |
Use these as starting settings and verify the result in Play. The build notes contain the same steps in a text file for use beside the editor.
Build it, one step at a time
- Step 01
Make a collision you can repeat
Object palette → floor and falling object → Object SettingsPlace a Static floor and a Dynamic object a short distance above it. Leave Is Sensor off for both. Enter Play once without particles to confirm the object actually falls onto the floor, then return to the editor.
Check your resultThe same simple impact can be replayed while you tune the effect.
Open the related reference - Step 02
Build a finite burst
Expanded right menu → Particle Editor → PresetChoose Metal Sparks. For each active emitter, use Pattern: Impulses, turn Repeat impulses off and set Impulse count: 1. Keep the preset’s other values initially. Press Restart and watch until all particles disappear.
Check your resultThe effect emits a brief burst and finishes without continuously generating new particles.
Open the related reference - Step 03
Save and attach the effect
Particle Editor → Save → select falling object → Particle SettingsSave the effect as Impact Sparks. Select the falling object, open Particle Settings and choose it through Particle Effect. Set Play Particles Scale: 1 and leave Enable Contact Force off for the first test.
Check your resultParticle Effect names the effect you just saved.
Open the related reference - Step 04
Enable contact playback
Falling object → Particle Settings → contact optionsTurn Play Particles On Contact on and Play Particles When Created off. Start with a low Minimum Contact Force To Play Particles. Enable Rotate Particle Toward Contact Normal; adjust Rotation Offset after checking the direction in Play.
Check your resultPlayback is configured for a qualifying contact rather than object creation.
Open the related reference - Step 05
Find a useful threshold
Level → Play → adjust Minimum Contact ForceReplay the drop. If the burst appears, raise the minimum force gradually until gentle touches stop triggering it while the intended impact still does. Test a low and a higher drop. There is no single force value for every object: mass and impact speed change the result.
Check your resultA deliberate hit produces sparks while weaker contacts are filtered as intended.
Open the related reference - Step 06
Refine and save
Particle Settings → position, rotation and scale → Save LevelIf needed, use Enable Position Offset, Radius and Angle to place the effect origin near the visible hit. Keep testing the rotation. Add contact-force scaling only after the fixed-size effect works. Save and reopen the level, then repeat the drop.
Check your resultThe intended hit produces a short, correctly oriented burst after the level is reopened. Separate contacts can each trigger their own burst.
Open the related reference
Check your build
If something looks wrong
The impact produces no sparks
Check the Particle Effect selection, Play Particles On Contact and the minimum contact force. Confirm a real solid collision: sensors and collision filters can change the contact response.
Sparks play at the start of the level
Turn Play Particles When Created off on the object while testing contact playback.
Sparks keep repeating
Check every active emitter for Repeat impulses. A one-impulse effect can still be started again by separate qualifying contacts; raise the contact threshold if small repeated hits should be ignored.
The burst faces the wrong way
Inspect Rotate Particle Toward Contact Normal and tune Rotation Offset. Particle-simulation deflectors do not automatically reproduce the level’s collision geometry.