So I am hot on the trail of volumetric systems for us though after this weekend I will have to shift focus to paying work… but that’s another story.

ANYWAYS I got this:

https://playground.babylonjs.com/#6Z7SIZ

Where it like 95% works… I am having some trouble with my maths…

If you notice the raymached sphere (the blue one) scales differently then the rest of the scene. I have a sneaking suspicion it has to do with:

```
vec3 ssToPos(){
vec4 ndc = vec4(
(vUV.x - 0.5) * 2.0,
(vUV.y - 0.5) * 2.0,
1.0,
1.0
);
mat4 invMat = inverse(camProjection*camView);
vec4 clip = invMat * ndc;
return (clip / clip.w).xyz;
}
```

which is added to the direction of my camera to give me a ray direction, which without it seems to really extend the distortion effect. Maybe I need a transform calculation too or something?