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Simple Cross Section Shader

Discussion in 'Shaders' started by apple_motion, Nov 14, 2009.

  1. apple_motion

    apple_motion

    Joined:
    Jul 2, 2009
    Posts:
    169
    Garth-Smith likes this.
  2. Daniel-Brauer

    Daniel-Brauer

    Unity Technologies

    Joined:
    Aug 11, 2006
    Posts:
    3,314
  3. apple_motion

    apple_motion

    Joined:
    Jul 2, 2009
    Posts:
    169
    Thanks for the link Daniel ! I just learnt how to use Shader.SetGlobalMatrix() from there :)

    Also, we seem to use the same method, except I just made everthing inside the shader. (because, I am lazy :p)

    Here is the test code of mine version... (diffuse shading only at the moment)
    Code (csharp):
    1. // Fast Edition - Single Pass
    2.  
    3. Shader "cross_section_v003"
    4. {
    5.     Properties
    6.     {
    7.         section_depth ("section depth (x, y, z, depth)", vector) = (0,0,0,0.15)
    8.         section_color ("section color", color) = (0.5,0.1, 0.1, 1)
    9.        
    10.         color_map ("color map", 2D) = "white" {}
    11.        
    12.     }  
    13.     SubShader
    14.     {  
    15.         Pass
    16.         {          
    17.             CULL OFF
    18.            
    19. CGPROGRAM //--------------
    20. #pragma vertex   vertex_shader
    21. #pragma fragment fragment_shader
    22.  
    23. #include "UnityCG.cginc"
    24.  
    25. uniform float4 section_depth;
    26. uniform float4 section_color;
    27. uniform sampler2D color_map;   
    28.  
    29. float4x4 rotate(float3 r)
    30. {
    31.     float3 c, s;
    32.     sincos(r.x, s.x, c.x);
    33.     sincos(r.y, s.y, c.y);
    34.     sincos(r.z, s.z, c.z);
    35.     return float4x4( c.y*c.z,    -s.z,     s.y, 0,
    36.                          s.z, c.x*c.z,    -s.x, 0,
    37.                         -s.y,     s.x, c.x*c.y, 0,
    38.                            0,       0,       0, 1 );
    39. }
    40.  
    41. struct a2v
    42. {
    43.     float4 vertex   : POSITION;
    44.     float4 color    : COLOR;
    45.     float2 texcoord : TEXCOORD;
    46.     float3 normal   : NORMAL;
    47. };
    48.  
    49. struct v2f
    50. {
    51.     float4 position : POSITION;
    52.     float2 texcoord : TEXCOORD0;                               
    53.     float3 normal   : TEXCOORD1;
    54.     float4 vertex   : TEXCOORD2;
    55.     float4 mask     : TEXCOORD3;               
    56. };
    57.                
    58. v2f vertex_shader( a2v IN )
    59. {                                                  
    60.     v2f OUT;
    61.                
    62.     float4x4 r   = rotate(radians(section_depth.xyz) +_SinTime.xyz);
    63.     float4 c     = float4(IN.vertex.xyz,1);
    64.    
    65.     OUT.mask     = mul(r, c);
    66.     OUT.position = mul(glstate.matrix.mvp, IN.vertex);
    67.     OUT.texcoord = IN.texcoord;
    68.     OUT.normal   = IN.normal;
    69.     OUT.vertex   = IN.vertex;
    70.    
    71.     return OUT;
    72. }
    73.                            
    74. void fragment_shader(   v2f IN,
    75.                         out float4 finalcolor : COLOR) 
    76.                        
    77. {
    78.     if(IN.mask.x > section_depth.w)
    79.         discard;
    80.        
    81.     float3 obj_view_dir = IN.vertex.xyz - _ObjectSpaceCameraPos;
    82.     float fd = dot(obj_view_dir, IN.normal);
    83.     float3 N = (fd > 0) ? float3(1,0,0) : IN.normal;
    84.        
    85.     N = mul(glstate.matrix.invtrans.modelview[0], float4(N, 1));               
    86.     float diffuse = saturate(dot(glstate.light[0].position, N));
    87.    
    88.     finalcolor = float4(0,0,0,1);                              
    89.     if (fd > 0)
    90.     {
    91.         finalcolor.xyz = section_color *(diffuse *0.6 +0.4);
    92.         return;
    93.     }              
    94.     finalcolor.xyz = tex2D(color_map, IN.texcoord).xyz *(diffuse *0.6 +0.4);
    95. }
    96. ENDCG //--------------
    97.  
    98.         } // Pass
    99.     } // SubShader
    100. } // Shader
    (Remark: the " +_SinTime.xyz" could be deleted. That's just for the demo)

    EDIT: The old attachment "cross_section_v004.shader" has been replaced by the following one.
    Code (csharp):
    1. r *= float4x4(1,-1,-1, 0, -1, 1,-1, 0, -1,-1, 1, 0, 0, 0, 0, 1 );
    (In the "004a" version, one more line is added onto it. since, the "section_depth.xyz" need to be inverted before assign to the cap's normal.)
     

    Attached Files:

  4. antenna tree

    antenna tree

    Joined:
    Oct 30, 2005
    Posts:
    5,325
    Cool shader, thanks for sharing it. How are you hollowing out the spheres in the video?
     
  5. apple_motion

    apple_motion

    Joined:
    Jul 2, 2009
    Posts:
    169
    Simply model it, a small flipped-face sphere inside a bigger sphere :)

    In fact, you bring out a very good idea, why not add a "thicker" function onto the shader too. so that, I don't need to touch the modeling program anymore. (... save up some time to enjoy my coffee :p)

    Many Thanks !
     
  6. monark

    monark

    Joined:
    May 2, 2008
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    1,311
    In my version I add a simple lighting equation to the cut surface too, that way it doesn't always have to be constant shaded. Nice that you managed to get all the clipping code into the shader though, very handy for clipping different objects with different planes.
     
  7. apple_motion

    apple_motion

    Joined:
    Jul 2, 2009
    Posts:
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    Surely, I will add this in my code later :)

    In fact, I still looking for the way to work with intersecting closed objects, by making a real cap :p

    I have this now...
    [​IMG]

    (2 spheres, left with "cross section" shader and right with diffuse shader)

    I am working on this method now... re-assign the depth value, but not success when the angle of the clipping plane is changed :s

    in vertex_shader...
    Code (csharp):
    1. float4 c     = float4(IN.vertex.xyz,1);
    2. OUT.vpos     = mul(glstate.matrix.modelview[0], c);
    in fragment_shader...
    Code (csharp):
    1. float3 N = IN.normal;
    2. float z = IN.vpos.z;
    3.  
    4. if (IN.vpos.z > section_depth.w)
    5. {  
    6.     N = float3(1,0,0);
    7.     z = section_depth.w;
    8. }
    9.  
    10. float near = _ProjectionParams.y;
    11. float far  = _ProjectionParams.z;
    12.  
    13. float a = -far/(far-near);
    14. float b = -far*near/(far-near);
    15. depth   = (a*z+b)/(-z);
    Any new idea ??
     
  8. monark

    monark

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    I guess you'd actually need to project the x,y coordinate onto the clipping plane to get the depth and then test if the object depth was behind.

    This is a very interesting approach, I really need to solve the intersection problem to make this useful for what I want and what you are suggesting here is interesting. The question is how do you determine what is "inside" so as to only test the depth for the bits that should be capped? When 2 objects intersect you can't rely on the normals any more.
     
  9. Peter Hou

    Peter Hou

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    Oct 12, 2010
    Posts:
    66
    The attached shader doesn't appear to work in Unity 3.1 - is it still under development?
     
  10. apple_motion

    apple_motion

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    Jul 2, 2009
    Posts:
    169
    because that poor guy still using unity 2.6 to do the development.... in fact, the development will be resumed very soon :)
     
  11. kenshin

    kenshin

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    Apr 21, 2010
    Posts:
    909
    Hello Apple_motion, your work is very interesting.

    Did you updated the shader for Unity 3.3?
     
  12. diablo

    diablo

    Joined:
    Jan 3, 2011
    Posts:
    736
    Hi Apple_Motion,

    I second the request for a Unity 3.3 update! Anyone else interested in this?

    El Diablo
     
  13. diablo

    diablo

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    Jan 3, 2011
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    736
    bump! Unity 3.3 update, willing to pay!! Apple motion, where are you?
     
  14. qholmes

    qholmes

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    Sep 17, 2010
    Posts:
    162
    Yes bump here too??

    Q
     
  15. diablo

    diablo

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    736
  16. TiG

    TiG

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    Feb 28, 2011
    Posts:
    308
    bump
     
  17. diablo

    diablo

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    736
  18. solmyr-fr

    solmyr-fr

    Joined:
    Jun 18, 2009
    Posts:
    19
    I wanted to do the same thing and I believe the problem was because Unity 3 use Surface shader (so things are handled in another way ...)

    The instruction "clip" can be used in the surface function . For instance, for a plane which the equation is a.x +b.y + c.z + d = 0 :

    Code (csharp):
    1.  
    2. Shader "Custom/ClipShader"
    3. {
    4.    Properties
    5.    {
    6.       _MainTex ("Texture", 2D) = "white" {}
    7.       _a ("_a",Float) = 0.0
    8.       _b ("_b",Float) = 0.0
    9.       _c ("_c",Float) = 0.0
    10.       _d ("_d",Float) = 0.0
    11.       _clip ("_clip",Float) = 0
    12.     }
    13.     SubShader {
    14.       Tags { "RenderType" = "Opaque" }
    15.       Cull Off
    16.       CGPROGRAM
    17.       #pragma surface surf Lambert
    18.       struct Input {
    19.           float2 uv_MainTex;
    20.           float3 worldPos;
    21.       };
    22.      
    23.       sampler2D _MainTex;
    24.       float _a,_b,_c,_d,_clip;
    25.  
    26.       void surf (Input IN, inout SurfaceOutput o)
    27.       {
    28.           if(_clip == 1)
    29.           {
    30.              clip (_a *IN.worldPos.x +
    31.                 _b *IN.worldPos.y +
    32.                 _c *IN.worldPos.z +
    33.                 _d > 0 ? -1 :1);
    34.          }
    35.  
    36.           o.Albedo = tex2D (_MainTex, IN.uv_MainTex).rgb;
    37.       }
    38.       ENDCG
    39.     }
    40.     Fallback "Diffuse"
    41.   }
    42.  
    In a Unity script; you can activate the clipping plan using Shader.SetGlobalFloat("_clip",1); and move the plan along its normal using Shader.SetGlobalFloat("_d",d); However it seems that you must unexpose the variables from the property block if you want a Shader.SetGlobal function to work.


    You can of course do a script to compute _a _b _c _d parameters according to a plan (gameobject) inside the scene to let the user create easily a clipping plane with a desired orientation;

    You can rewrite other defaut Unity shaders (bump, alpha, etc...) , you'll juste have to add some properties and the clip instruction.

    Hope it will help you :) ,
    Tom
     
    Last edited: Aug 26, 2011
  19. diablo

    diablo

    Joined:
    Jan 3, 2011
    Posts:
    736
    Solmyr, I'm *just* starting to dive into learning the shader language so this is still over my head. Are you saying that the shader code you provided is a surface shader that replaces the vertex/fragment shader AppleMotion posted earlier in this thread? I'm learning the shader language (just started reading the book "The Cg Tutorial" this morning) for the specific purpose of creating the type of shader AppleMotion demonstrated in the gray sphere example, where you can define a plane that intersects an object and the shader will clip a portion of the object and fill it with a color (though I would prefer a texture). I've posted here and to other threads numerous times asking AppleMotion to update his shader and private messaged him a few times as well, offering to pay him but he never ever replies to anyone's requests or messages, so I decided to just learn and do it on my own lol.
     
    Last edited: Sep 2, 2011
  20. solmyr-fr

    solmyr-fr

    Joined:
    Jun 18, 2009
    Posts:
    19
    No, it's not an update because it doesn't work the same way.
    It just uses the "clip(-1)" function in the surface shader to exclude pixel that will be on one side of the plane for objects that use this shader so it creates a hole in the object.

    I havent code the part to fill the intersected zone with a color/texture. I don't know how to do it but you can however easily change the color of a small part of the original object surface wich is near the clipping plane.

    Code (csharp):
    1.  
    2. void surf (Input IN, inout SurfaceOutput o)
    3. {
    4.      float dist = _a *IN.worldPos.x +_b *IN.worldPos.y +_c *IN.worldPos.z +_d;
    5.       if(_clip == 1  abs(dist) < 0.02)[COLOR="yellowgreen"]// fill the near surface in yellow[/COLOR]
    6.       {
    7.         fixed4 c = fixed4(1,1,0,1);
    8.         o.Albedo = c.rgb;
    9.         o.Alpha = c.a;
    10.      }
    11.      else if(_clip == 1  dist < -0.02)  [COLOR="yellowgreen"]// exclude pixel outside the plane[/COLOR]
    12.      {
    13.          clip(-1);
    14.      }
    15.      else[COLOR="yellowgreen"] // normal diffuse display[/COLOR]
    16.      {
    17.         fixed4 c = tex2D(_MainTex, IN.uv_MainTex) * _Color;
    18.         o.Albedo = c.rgb;
    19.         o.Alpha = c.a;
    20.      }
    21. }
    22.  
     
  21. diablo

    diablo

    Joined:
    Jan 3, 2011
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    736
    Ahhh, I see, this does the clipping but doesn't fill it in. Here's another bump.
     
  22. diablo

    diablo

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    736
    bumped
     
  23. kurylo3d

    kurylo3d

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    Nov 7, 2009
    Posts:
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    Hey I am using this shader in a tablet application, I was wondering if there are any ways to optimize it for better performance. When i zoom in and it encompasses the screen i just drop to like 2 fps.... I am not familiar with writing shaders ands I was wondering first is there a way to make it more optimized, and second... is there a way to make it so it only updates the cross section amount only when i change it with a script?
     
  24. Bezzy

    Bezzy

    Joined:
    Apr 1, 2009
    Posts:
    69
    I read somewhere in the mobile optimization section of unity that the discard function could be especially slow on mobile devices?

    http://unity3d.com/support/documentation/Manual/Optimizing Graphics Performance.html

    It's possible that a mesh based approach might be faster in this instance? Though perhaps not for everything in your scene all at once. Or perhaps to some tricks with multiple camera clipping planes? There's a some settings on the camera to set up individual clipping planes per layer:

    http://unity3d.com/support/documentation/ScriptReference/Camera-layerCullDistances.html

    Unfortunately, it doesn't give access to NEAR clipping planes per layer, so you may have to forgo this approach and have multiple cameras, pehaps?
     
  25. Hummelwalker

    Hummelwalker

    Joined:
    Oct 28, 2010
    Posts:
    119
    Hello,

    I'm not very familar with Shaders. Can anybody explain what I have to do with solmyr's shader to make a cross section?
     
  26. RyuMaster

    RyuMaster

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    Sep 13, 2010
    Posts:
    467
    Thank you very much!! It really works as I wanted it to. What abcd stand for? I want to feed it gameobject plane, should I pass transformation matrix or something like that?
     
  27. hippocoder

    hippocoder

    Digital Ape Moderator

    Joined:
    Apr 11, 2010
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    18,985
    If you don't mind it not being solid, you can render in a couple of passes, or just adjust the near clip plane of the 2nd camera rendering the object you want to cross section. By adjusting near clip, you do not have any overhead on mobile. Such sacrifices may be needed. To fill in the gaps will be far more expensive.
     
  28. RyuMaster

    RyuMaster

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    Sep 13, 2010
    Posts:
    467
    Ah, I see now, a == position.x, b == position.y and c == position.z
    "d" is a bit of mystery - I assume it just clips in one direction, when I adjust d. What it is actualy stands for in world-space? I want somehow to take plane rotation into account, and clip everything which is on a one side of it
     
  29. kurylo3d

    kurylo3d

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    Nov 7, 2009
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    1,118
    @hippocoder

    Yea i wanted to do that at first, but the problem is I have multiple objects on top of one another inside and out... So i cant seperate them with seperate cameras... it has to be done at the shader level.
     
  30. chrisirhc

    chrisirhc

    Joined:
    Jan 26, 2012
    Posts:
    1
    Thanks, interesting implemention of free clipping in surface shaders. However I cannot figure out how to manage some correct capping, if anyone has any clue...
     
  31. sjm-tech

    sjm-tech

    Joined:
    Sep 23, 2010
    Posts:
    621
    I know that it is a old thread ... but there is no other new resource regarding cross-section shaders... so for use the original apple_motion(thanks) shader in unity 3.5, whaiting a help of a expert shader user....you can remove the gles compiling errors excluding GLES renderers by adding "#pragma exclude_renderers gles" under "CGPROGRAM".
    I like very much the (fake) fill effect of the cross-section ...but it don't work well with intersected geometryes.
    Could be interesting to have a renew shader with an implementation of the filling of the section.
    Max
     

    Attached Files:

    Last edited: Jun 18, 2012
  32. Xeal

    Xeal

    Joined:
    Jul 10, 2012
    Posts:
    4
    As sjm tech says, it would be really useful to fill the section.

    I was thinking of extracting a silhouette texture from the shader and then apply it like a cookie-cutter to a Plane mesh.
    However, my shader's skills are not sufficient enough to do it...

    Does anyone has already done something similar, or have some clues to begin with ?
     
  33. proso

    proso

    Joined:
    May 24, 2012
    Posts:
    67
    I'm looking for something like this. Not a shader, but a tool that can clip a whole object (ofcourse with fill). Is there something like that? Or is someone willing to make that? I think more people can use this.
     
  34. thomes

    thomes

    Joined:
    Dec 6, 2012
    Posts:
    7
    hello

    hope for a little help with giving over the gui-slidervalue to the clipshader parameters _d.

    i found a javascript for the GUIslider.now i need the value XXX in the script below to change the clipshader _d value


    many thanks for help
    thomes

    [​IMG]
     
    Last edited: Dec 14, 2012
  35. thomes

    thomes

    Joined:
    Dec 6, 2012
    Posts:
    7
    please, i know it seems easy for you, but it woul´d be nice to get help for my question.please also see post above

    i tried to access the float-property "_d" in the clipshadermat with things like this...

    renderer.material.float_d = hSliderValue;

    but this and any other tries did not work.

    if anyone coul´d explain me in 2 sentences the right way

    big thanks for your time
    thomes
     
    Last edited: Dec 21, 2012
  36. Cascho01

    Cascho01

    Joined:
    Mar 19, 2010
    Posts:
    950
    Could someone change sjm techs shader so that the section color is emissive?

    Wouldn´t it theoretically work to project a texture onto the flipped inner surfaces?
     
    Last edited: Jan 16, 2013
  37. sjm-tech

    sjm-tech

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    just to clarify... the shader was made by apple_motion (all credit to him) i make only a small fix to make it usable in 3.5...
    after this clarification...could be nice to have a new version with some improvements!
     
  38. bilke

    bilke

    Joined:
    Jul 13, 2012
    Posts:
    50

    Attached Files:

  39. Alan47

    Alan47

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    Mar 5, 2011
    Posts:
    105
    @bilke: I just downloaded your edited version and I'm still getting two compile errors. Could you perhaps be so kind and fix the errors, since I've no idea about shaders internals... ^_^'

    Also, a quick example on how to control the cut plane would be very helpful.

    Thanks,


    Alan
     
  40. ripol

    ripol

    Joined:
    Oct 23, 2012
    Posts:
    17
    Hi,

    I was looking to exactly this kind of shader, I'm just starting working with them, So can you plz show some example using this shader or can you explain me how can I use it.

    Thank you in advance

    rp
     
  41. tomekkie2

    tomekkie2

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    Jul 6, 2012
    Posts:
    299
    Hey, @sjm tech, I was just playing with various shaders. (on 4.3 Pro)
    I don't know much about shaders, but one from this thread seemed to lose the baked shadows.
    So I made a similar one, this time basing on the "slices" example from Unity docs:

    http://docs.unity3d.com/Documentation/Components/SL-SurfaceShaderExamples.html

    It required definately less lines of code and shadows (on the front faces, none on the backfaces) are preserved.
    I am wondering now whether it would be possible to make a version for transparent materials.
     
    Last edited: Dec 16, 2013
  42. sjm-tech

    sjm-tech

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    Sep 23, 2010
    Posts:
    621
    Hi tomekkie2, I also don't know much about shaders :(.
    I hope that a shader guru can give you more interesting answers.
    Max
     
    Last edited: Dec 16, 2013
  43. tomekkie2

    tomekkie2

    Joined:
    Jul 6, 2012
    Posts:
    299
    The outcome of my experiments can be seen here:

    $sect.jpg

    My choice of free Unity models possibly makes this to look attractive but doesn't doesn't give good results, because often the meshes in general are opened, with no backfaces where would not be seen, no faces on the bottom.

    On the contrary, most technical meshes are closed.

    So this is just a surface "slices" shader from Unity docs examples with a few lines deleted/added.

    The webplayer is here.
     
  44. kreios

    kreios

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    Sep 1, 2012
    Posts:
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    @tomekkie2,
    thats really awesome. Is there any chance of posting your code?
     
  45. Ippokratis

    Ippokratis

    Joined:
    Oct 13, 2008
    Posts:
    1,437
    Happy 2014.
    Code (csharp):
    1. Shader "IppokratisBournellis/SectionPlane"
    2. {
    3.     Properties
    4.     {
    5.       _MainTex ("Texture", 2D) = "white" {}
    6.       _section ("Section plane (x angle, y angle, z angle, w displacement)", vector) = (0,0,0,0.15)
    7.       _Color ("Section Color", Color) = (1,1,1,0)
    8.     }
    9.    
    10.     SubShader
    11.     {
    12.       Tags { "RenderType" = "Opaque" }
    13.       Cull Off
    14.    
    15.       CGPROGRAM
    16.       #pragma surface surf Lambert
    17.  
    18.       struct Input
    19.       {
    20.           float2 uv_MainTex;
    21.           float3 worldPos;
    22.           float3 viewDir;
    23.           float3 worldNormal;
    24.       };
    25.      
    26.       sampler2D _MainTex;
    27.       sampler2D _BumpMap;
    28.       float4 _section;
    29.       fixed4 _Color;
    30.      
    31.       void surf (Input IN, inout SurfaceOutput o)
    32.       {
    33.         float toClip = _section.x * 0.1 * IN.worldPos.x +
    34.                        _section.y * 0.1 * IN.worldPos.y +
    35.                        _section.z * 0.1 * IN.worldPos.z +
    36.                        _section.w;
    37.                        
    38.         clip( toClip);
    39.          
    40.         float fd = dot( IN.viewDir, IN.worldNormal);
    41.  
    42.         if (fd.x > 0)
    43.         {
    44.             o.Albedo = tex2D (_MainTex, IN.uv_MainTex).rgb;
    45.             return;
    46.         }
    47.        
    48.         o.Emission = _Color;
    49.       }
    50.       ENDCG
    51.     }
    52.     Fallback "Diffuse"
    53.  }
    $Screen Shot 2014-01-08 at 9.15.03 PM.png
     
    Last edited: Jan 8, 2014
    shanecelis likes this.
  46. tomekkie2

    tomekkie2

    Joined:
    Jul 6, 2012
    Posts:
    299
    Hey, Ippokratis, I have also tried to make it in one pass in both surface as well as vertex shaders, basing on dot between viewing and normal, but I keep on getting a crossection color on the edge:

    $screenshot1.jpg

    I don't get any edge artifacts when I going with two passes.
     
  47. Ippokratis

    Ippokratis

    Joined:
    Oct 13, 2008
    Posts:
    1,437
    Yes, I observed it as well. It became less obvious when I used a high poly sphere.
    Using two passes seems a better approach, thanks for mentioning.
     
  48. m_bec

    m_bec

    Joined:
    Feb 3, 2014
    Posts:
    3
    Hi Ippokratis,

    If it's not too much trouble, would you mind explaining in simpler terms what's going on in the shader and how someone with no extensive Unity experience might use it?

    If I create a sphere and apply the shader, should it work automatically? Or do I apply the shader to a plane and have the plane intersect the sphere?

    Thanks!

    EDIT: Nevermind, I am an idiot. Figured it out!
     
    Last edited: Feb 3, 2014
  49. m_bec

    m_bec

    Joined:
    Feb 3, 2014
    Posts:
    3
    Hi Ippokratis,

    Is there a way to edit your shader so that it also has alpha values that can be increased/decreased from another script?

    Thanks!
     
  50. solmyr-fr

    solmyr-fr

    Joined:
    Jun 18, 2009
    Posts:
    19
    m_bec : on what part of your object do ou want the alpha value ?
    -> on the clipped part : not possible by definition because the instruction "clip()" of the shader implies that concerned polygons are not rendered by your GPU.
    -> the remaining part : yes, do not forget "#pragma surface surf Lambert alpha" and to set your output "SurfaceOutput o" alpha value "o.Alpha = _Color.a;"

    Example : a human heart with 2 clipping planes
    - some meshes use a default unity shader (the internal cavities) and are not affected by the clipping plane
    - some others meshes (external parts of the heart) use the clip plane shader and are cut by the 2 clipping planes.

    EDIT : even with 2 pass, you can have some ugly artefacts with alpha ... so I recommand to keep the shader as a Opaque.

    $example.jpg
     
    Last edited: Feb 20, 2014