<p>This looks like a bug in Nuke's <code>ParticleBounce</code> node. The <code>geometry</code> input is new to Nuke 9, which was released pretty recently.</p>
<p>That said, the bug seems to manifest only in this idealized environment of two spheres. The first sphere (radius 1) emits the particles, and the second sphere (radius 3) kills them. It is likely because of the exact alignment between vertices that causes it to penetrate.</p>
<p><strong>Rotating one of the two spheres 0.1 degrees on each axis solves the problem</strong></p>
<p>In theory, the &quot;real world&quot; wouldn't see this bug as frequently, but I've submitted this bug report to The Foundry.</p>
<hr />
<h2>Response from The Foundry</h2>
<blockquote>
<p>Thanks very much for providing reproduction script, we can see the
problem easily. Your comments and script are logged:</p>
<p>Bug 47417 - ParticleBounce - Leaks with static primitive geometry
input in some cases</p>
<p>We recommend checking upcoming release notes for updates on this
issue.</p>
</blockquote>

CC BY-SA 3.0
2015-01-15T02:33:28.917Z
2015-01-26T22:27:43.910Z
2020-06-17T09:53:03.607Z
mhlester
<p>I created a sphere emitting particles in Nuke. Around that sphere is another sphere connected to a particle bounce which is set to kill the particles. Some particles seem to slip through though. Why is this, and how can I fix it?</p>

<p><img src="https://i.sstatic.net/SodjL.png" alt="Nodes">
<img src="https://i.sstatic.net/RMLUT.jpg" alt="Viewer with particle escaping"></p>

<pre><code>    #! /Applications/Nuke9.0v3/Nuke9.0v3.app/Contents/MacOS//libnuke-9.0.3.dylib -nx
version 9.0 v3
define_window_layout_xml {&lt;?xml version="1.0" encoding="UTF-8"?&gt;
&lt;layout version="1.0"&gt;
    &lt;window x="0" y="23" w="1440" h="873" screen="0"&gt;
        &lt;splitter orientation="1"&gt;
            &lt;split size="910"/&gt;
            &lt;splitter orientation="1"&gt;
                &lt;split size="34"/&gt;
                &lt;dock id="" hideTitles="1" activePageId="Toolbar.1"&gt;
                    &lt;page id="Toolbar.1"/&gt;
                &lt;/dock&gt;
                &lt;split size="872"/&gt;
                &lt;splitter orientation="2"&gt;
                    &lt;split size="497"/&gt;
                    &lt;dock id="" activePageId="Viewer.1" focus="true"&gt;
                        &lt;page id="Viewer.1"/&gt;
                    &lt;/dock&gt;
                    &lt;split size="350"/&gt;
                    &lt;dock id="" activePageId="DAG.1"&gt;
                        &lt;page id="DAG.1"/&gt;
                        &lt;page id="Curve Editor.1"/&gt;
                        &lt;page id="DopeSheet.1"/&gt;
                    &lt;/dock&gt;
                &lt;/splitter&gt;
            &lt;/splitter&gt;
            &lt;split size="526"/&gt;
            &lt;dock id="" activePageId="Properties.1"&gt;
                &lt;page id="Properties.1"/&gt;
            &lt;/dock&gt;
        &lt;/splitter&gt;
    &lt;/window&gt;
&lt;/layout&gt;
}
Root {
 inputs 0
 name /particle.nk
 frame 47
 format "2048 1556 0 0 2048 1556 1 2K_Super_35(full-ap)"
 proxy_type scale
 proxy_format "1024 778 0 0 1024 778 1 1K_Super_35(full-ap)"
}
Sphere {
 inputs 0
 display wireframe
 render_mode off
 radius 3
 name Sphere1
 xpos -417
 ypos 81
}
Sphere {
 inputs 0
 name Sphere2
 xpos -410
 ypos -50
}
Sphere {
 inputs 0
 display wireframe
 render_mode off
 name Sphere3
 xpos -266
 ypos -144
}
push 0
ParticleEmitter {
 inputs 3
 name ParticleEmitter1
 xpos -261
 ypos -50
}
ParticleBounce {
 inputs 2
 out_bounce_mode kill
 in_bounce_mode kill
 object input
 name ParticleBounce1
 selected true
 xpos -261
 ypos 77
}
Viewer {
 frame 47
 frame_range 1-100
 name Viewer1
 xpos -261
 ypos 176
}
</code></pre>

CC BY-SA 3.0
2015-01-13T13:36:00.510Z
If the geometry is animated with a displace geo and some noise it is even worse.
Benedikt
CC BY-SA 3.0
2015-01-14T04:52:26.147Z
Could you copy/paste the nodes into the question as `code` so the problem can be reproduced?
mhlester
CC BY-SA 3.0
2015-01-14T15:05:46.077Z
@mhlester added it
Benedikt
CC BY-SA 3.0
2015-01-26T22:28:06.757Z
updated my answer with the response from the foundry. good find!
mhlester
<nuke>
Nuke particles escaping bounce node with geometry input
Benedikt
# Nuke particles escaping bounce node with geometry input

(Asked by: username_0 on 2015-01-13)

I created a sphere emitting particles in Nuke. Around that sphere is another sphere connected to a particle bounce which is set to kill the particles. Some particles seem to slip through though. Why is this, and how can I fix it?


    #! /Applications/Nuke9.0v3/Nuke9.0v3.app/Contents/MacOS//libnuke-9.0.3.dylib -nx
version 9.0 v3
define_window_layout_xml {

    
        
            
            
                
                
                    
                
                
                
                    
                    
                        
                    
                    
                    
                        
                        
                        
                    
                
            
            
            
                
            
        
    

}
Root {
 inputs 0
 name /particle.nk
 frame 47
 format "2048 1556 0 0 2048 1556 1 2K_Super_35(full-ap)"
 proxy_type scale
 proxy_format "1024 778 0 0 1024 778 1 1K_Super_35(full-ap)"
}
Sphere {
 inputs 0
 display wireframe
 render_mode off
 radius 3
 name Sphere1
 xpos -417
 ypos 81
}
Sphere {
 inputs 0
 name Sphere2
 xpos -410
 ypos -50
}
Sphere {
 inputs 0
 display wireframe
 render_mode off
 name Sphere3
 xpos -266
 ypos -144
}
push 0
ParticleEmitter {
 inputs 3
 name ParticleEmitter1
 xpos -261
 ypos -50
}
ParticleBounce {
 inputs 2
 out_bounce_mode kill
 in_bounce_mode kill
 object input
 name ParticleBounce1
 selected true
 xpos -261
 ypos 77
}
Viewer {
 frame 47
 frame_range 1-100
 name Viewer1
 xpos -261
 ypos 176
}

**Tags:** nuke

> **Comments:**
> **username_0**: If the geometry is animated with a displace geo and some noise it is even worse.  
> **username_1**: Could you copy/paste the nodes into the question as `code` so the problem can be reproduced?  
> **username_0**: @username_1 added it  
> **username_1**: updated my answer with the response from the foundry. good find!  

---

## 1 answers

### Answer by username_1 on 2015-01-15. Score: 4 | Accepted answer

This looks like a bug in Nuke's `ParticleBounce` node. The `geometry` input is new to Nuke 9, which was released pretty recently.

That said, the bug seems to manifest only in this idealized environment of two spheres. The first sphere (radius 1) emits the particles, and the second sphere (radius 3) kills them. It is likely because of the exact alignment between vertices that causes it to penetrate.

**Rotating one of the two spheres 0.1 degrees on each axis solves the problem**

In theory, the "real world" wouldn't see this bug as frequently, but I've submitted this bug report to The Foundry.

---

## Response from The Foundry

> Thanks very much for providing reproduction script, we can see the
> problem easily. Your comments and script are logged:
>
> Bug 47417 - ParticleBounce - Leaks with static primitive geometry
> input in some cases
>
> We recommend checking upcoming release notes for updates on this
> issue.


---

