Mesh rotation and ray marching

I've written a simple ray marcher in ShaderLab to visualize some 3D textures. Right now I'm applying the material to a cube and everything looks fine when the cube is at euler angles (0,0,0) but the more the cube is rotated the less predictable changes resulting from small movements in camera perspective become and the more two-dimensional the shader appears.

I'm wondering how I would I best go about rotating 3D textures used in a ray marching shader, optimally I could just rotate the mesh itself and the shader would rotate intuitively along with it. I've tried rotating the uvw's in the shader itself but nothing seems to be working so I assume the problem lies in how i'm setting up my uvw's but I don't really know.

At the moment here is how i'm setting my UVW's:

Code (CSharp):

1.     void Calculate3DTexUVW()
2.     {
3.         List<Vector3> UVWs = new List<Vector3>();
4.  
5.         for (int i = 0; i < meshFilter.sharedMesh.vertices.Length; i++)
6.         {
7.             UVWs.Add(new Vector3(meshFilter.sharedMesh.vertices[i].x,
8.                 meshFilter.mesh.vertices[i].y,
9.                 meshFilter.mesh.vertices[i].z));
10.             if (UVWInWorldCoordinates) //toggle to make uvw's independant of mesh vertices
11.             {
12.                 UVWs[i] = transform.TransformPoint(UVWs[i]);
13.             }
14.         }
15.  
16.         meshFilter.sharedMesh.SetUVs(0, UVWs);
17.     }

Here is a version of the ray marcher:

Code (CSharp):

1. Shader "Custom/SpecieShaderPlane"
2. {
3.     Properties
4.     {
5.         _MainTex3D("MainTex 3D", 3D) = "red" {}
6.         _Color("Specie Color", Color) = (1,1,1,1)
7.         _Intensity("Intensity", Range(0,1)) = 0.1
8.         _Threshold("Min Threshold", Range(0,1)) = 0.5 //cut off alpha
9.         _StepSize("Penetration Step Size", Range(0,0.1)) = 0.05
10.         _StepNumber("Step Number (times to propogate ray)", Range(0,512)) = 64
11.     }
12.         SubShader
13.         {
14.             Tags { "Queue" = "Transparent" "RenderType" = "Transparent" }
15.             Blend SrcAlpha OneMinusSrcAlpha
16.             ZWrite On
17.             Cull Back
18.             Pass
19.             {
20.                 CGPROGRAM
21.                 #pragma vertex vert
22.                 #pragma fragment frag
23.  
24.                 #include "UnityCG.cginc"
25.                 #include "UnityShaderVariables.cginc"
26.  
27.                 struct appdata
28.                 {
29.                     float4 mVert : POSITION; //model vertex position
30.                     float3 UVW : TEXCOORD0;
31.                 };
32.  
33.                 struct v2f
34.                 {
35.                     float3 UVWTransformed : TEXCOORD0;
36.                     float4 cVert : SV_POSITION; //clip vertex position
37.                     float4 wVert : POSITION1; //world vertex position
38.                     float3 camToFragDir : POSITION2; //unit vector representing direction
39.                 };
40.  
41.                 sampler3D _MainTex3D;
42.                 float4x4 _UVWTransform; //set in c# script
43.                 v2f vert(appdata input)
44.                 {
45.                     v2f o;
46.                     o.cVert = UnityObjectToClipPos(input.mVert); //model-clip transform
47.                     o.wVert = mul(unity_ObjectToWorld, input.mVert); //model-world transform
48.  
49.  
50.                     o.UVWTransformed = mul(_UVWTransform, float4(input.UVW, 1)).xyz; //transform uvw
51.                     o.camToFragDir = normalize(o.wVert - _WorldSpaceCameraPos);
52.  
53.                     return o;
54.                 }
55.  
56.                 fixed4 _Color;
57.                 float _Intensity;
58.                 float _Threshold;
59.                 float _StepSize;
60.                 float _StepNumber;
61.  
62.                 fixed4 frag(v2f input) : SV_Target
63.                 {
64.                         float3 ray = { 0,0,0 }; //offset from surface to sample from
65.                         fixed4 col = { 0,0,0,0 };
66.  
67.                         //ray marching loop where a ray penetrates into a 3D texture and samples as it propagates
68.                         for (int i = 0; i < _StepNumber; i++) {
69.                             fixed4 currentSample = tex3D(_MainTex3D, input.UVWTransformed + ray);
70.                             if (currentSample.r < _Threshold) {
71.                                 currentSample.rgb = 0;
72.                             }
73.                            
74.                             col.a += (1 - col.a) * currentSample * _Intensity; // asymptotic transfer function
75.                             ray += input.camToFragDir * _StepSize; //propogate ray
76.                         }
77.                      
78.                         col.rgb = _Color.rgb;
79.                     return col;
80.                 }
81.                 ENDCG
82.             }
83.         }
84. }
85.  

And here is how I was setting my uvw transform matrix in c#

Code (CSharp):

1.     private void Transform(Vector3 pos, Vector3 rot, float sclInverse)
2.     {
3.         float t = Time.time;
4.         float scl = 1 / sclInverse;
5.  
6.         Quaternion rotQ = Quaternion.Euler(t * rot.x, t * rot.y, t * rot.z);
7.         Vector3 sclV = new Vector3(scl, scl, scl);
8.  
9.         Matrix4x4 mat = Matrix4x4.TRS(pos, rotQ, sclV);
10.         GetComponent<Renderer>().sharedMaterial.SetMatrix("_UVWTransform", mat);
11.     }

Thanks!