I managed to add the ofxVolumetrics addon to Ofelia and adapt the example.
Here is the patch and an explanation how to add addons to Ofelia:
https://github.com/Jonathhhan/volumetrics_example_ofelia
Maybe this is a good foundation for making a 3d game of life that runs on a shader...
A funny thing (but good to know), that took a lot of time, was that it is not allowed to use function names in ofxOfeliaPdBindings.h that include "upd"  and i was using updateVolumeData() from the addon. I had to change it to loadVolumeData (or something else without "upd").

Ofelia Volumetrics Example

Second example, basically the same patch, but with ofxCameraAnaglyph for a 3d view...
https://github.com/Jonathhhan/volumetrics_anaglyph_example_ofelia
Here is a screenshot: 
I tried to create the shader for a 3d game of life (adapted from my working 2d game of life shader https://github.com/Jonathhhan/PDGameofLifeshaderVersion):
#version 120 uniform sampler3D Tex0; uniform vec3 resolution; uniform float lCell_0; uniform float lCell_1; uniform float lCell_2; uniform float lCell_3; uniform float lCell_4; uniform float lCell_5; uniform float lCell_6; uniform float lCell_7; uniform float lCell_8; uniform float lCell_9; uniform float lCell_10; uniform float lCell_11; uniform float lCell_12; uniform float lCell_13; uniform float lCell_14; uniform float lCell_15; uniform float lCell_16; uniform float lCell_17; uniform float lCell_18; uniform float lCell_19; uniform float lCell_20; uniform float lCell_21; uniform float lCell_22; uniform float lCell_23; uniform float lCell_24; uniform float lCell_25; uniform float lCell_26; uniform float dCell_0; uniform float dCell_1; uniform float dCell_2; uniform float dCell_3; uniform float dCell_4; uniform float dCell_5; uniform float dCell_6; uniform float dCell_7; uniform float dCell_8; uniform float dCell_9; uniform float dCell_10; uniform float dCell_11; uniform float dCell_12; uniform float dCell_13; uniform float dCell_14; uniform float dCell_15; uniform float dCell_16; uniform float dCell_17; uniform float dCell_18; uniform float dCell_19; uniform float dCell_20; uniform float dCell_21; uniform float dCell_22; uniform float dCell_23; uniform float dCell_24; uniform float dCell_25; uniform float dCell_26; vec2 rule[27] = vec2[27]( vec2(lCell_0, dCell_0), vec2(lCell_1, dCell_1), vec2(lCell_2, dCell_2), vec2(lCell_3, dCell_3), vec2(lCell_4, dCell_4), vec2(lCell_5, dCell_5), vec2(lCell_6, dCell_6), vec2(lCell_7, dCell_7), vec2(lCell_8, dCell_8), vec2(lCell_9, dCell_9), vec2(lCell_10, dCell_10), vec2(lCell_11, dCell_11), vec2(lCell_12, dCell_12), vec2(lCell_13, dCell_13), vec2(lCell_14, dCell_14), vec2(lCell_15, dCell_15), vec2(lCell_16, dCell_16), vec2(lCell_17, dCell_17), vec2(lCell_18, dCell_18), vec2(lCell_19, dCell_19), vec2(lCell_20, dCell_20), vec2(lCell_21, dCell_21), vec2(lCell_22, dCell_22), vec2(lCell_23, dCell_23), vec2(lCell_24, dCell_24), vec2(lCell_25, dCell_25), vec2(lCell_26, dCell_26) ); int get(int x, int y, int z) { return int(texture3D(Tex0, (gl_FragCoord.xyz + vec3(x, y, z)) / resolution).r); } void main() { int sum = get(1, 1, 1) + get(1, 0, 1) + get(1, 1, 1) + get( 0, 1, 1) + get( 0, 1, 1) + get( 1, 1, 1) + get( 1, 0, 1) + get( 1, 1, 1) + get(1, 1, 0) + get(1, 0, 0) + get(1, 1, 0) + get( 0, 1, 0) + get( 0, 1, 0) + get( 1, 1, 0) + get( 1, 0, 0) + get( 1, 1, 0) + get(1, 1, 1) + get(1, 0, 1) + get(1, 1, 1) + get( 0, 1, 1) + get( 0, 1, 1) + get( 1, 1, 1) + get( 1, 0, 1) + get( 1, 1, 1); vec2 r = rule[sum]; if (get(0, 0, 0) == 1) { gl_FragColor = vec4(r.x, r.x, r.x, r.x); } else { gl_FragColor = vec4(r.y, r.y, r.y, r.y); }
But it does not work.
Perhaps I did something wrong with the shader, but I think it does not work because ofFbo() can not store 3d textures.
Not really sure about that... 
Very cool to see some of Ofelia's extensibility  and nice to see more shader examples (even if 3d seems not fully supported yet).
hjh

@ddw_music i think the 3d game of life shader works now. not that it is not supported, i just did not understand it. The only thing is, that ofFbo and ofTexture do not support 3d textures, but they need to be created with openGL (as far as I know, and what I did with help from ofxVolumetrics).
I only did not find a way to paint into the 3d texture yet, right know I need a .png image for every z dimension.
Here is a short example: