Question Project Blender 3d Mesh to RenderTexture?

I have a sculpted 3d object from blender and I would like to project it into a texture for further use. What would be your approach in solving this problem? Some use cases might be to create a map, or to gain a heightmap set of data for further use (i.e. find the highest point).

 

I was able to create a render texture and orthographic camera to produce what I was looking for as a starting point however it doesn't resolve how I might get the top layer of height data for processing. It seems like I would need some sort of sampling & projecting to get this grid of data into a heightmap (i.e. a 2 dimensional matrix with a height as value).

 

I was able to get an image rendered in blender which is getting me closer

After further research it looks like I could utilize the camera's depthTexture capabilities
Unity - Manual: Cameras and depth textures (unity3d.com)
How to view Camera's Depth Texture? - Unity Forum

 

I have something close but appear to be having issues getting the depth height value not being correct & overlapping geoemtry. Anyone with shader experience able to help? Really just trying to get a grayscale heightmap output to the SV_TARGET and just view the texture in the editor.

I was able to get this reference code working, but have since struggled to apply it properly for my use case William Chyr | Unity Shaders - Depth and Normal Textures (Part 1)

Code (CSharp):

1.  
2. using UnityEngine;
3.  
4. [RequireComponent(typeof(MeshFilter))]
5. public class DepthTextureGenerator : MonoBehaviour
6. {
7.     public int textureResolution = 512;
8.     public Shader depthShader;
9.  
10.     [HideInInspector]
11.     public Texture2D InspectorDepthTexture;
12.  
13.     private Camera depthCamera;
14.  
15.     public void RenderDepthTexture()
16.     {
17.         Mesh mesh = GetComponent<MeshFilter>().sharedMesh;
18.         if (mesh == null)
19.             return;
20.  
21.         if (depthCamera == null)
22.             depthCamera = CreateDepthCamera();
23.  
24.         RenderTexture previousActiveTexture = RenderTexture.active;
25.         RenderTexture depthRenderTexture = new RenderTexture(textureResolution, textureResolution, 0, RenderTextureFormat.ARGB32);
26.         RenderTexture.active = depthRenderTexture;
27.  
28.         depthCamera.targetTexture = depthRenderTexture;
29.         depthCamera.RenderWithShader(depthShader, "");
30.  
31.         InspectorDepthTexture = new Texture2D(textureResolution, textureResolution, TextureFormat.ARGB32, false);
32.         InspectorDepthTexture.ReadPixels(new Rect(0, 0, textureResolution, textureResolution), 0, 0);
33.         InspectorDepthTexture.Apply();
34.  
35.         RenderTexture.active = previousActiveTexture;
36.         DestroyImmediate(depthRenderTexture);
37.  
38.     }
39.  
40.     private Camera CreateDepthCamera()
41.     {
42.         GameObject depthCameraObject = new GameObject("DepthCamera");
43.         depthCameraObject.transform.parent = transform;
44.         depthCameraObject.transform.localPosition = new Vector3(0f, CalculateOrthographicSize() * 2f, 0f);
45.         depthCameraObject.transform.rotation = Quaternion.Euler(90f, 0f, 0f);
46.  
47.         Camera depthCam = depthCameraObject.AddComponent<Camera>();
48.         depthCam.depthTextureMode = DepthTextureMode.Depth;
49.         depthCam.enabled = false;
50.         depthCam.orthographic = true;
51.         depthCam.orthographicSize = CalculateOrthographicSize();
52.         depthCam.clearFlags = CameraClearFlags.SolidColor;
53.         depthCam.backgroundColor = Color.cyan;
54.  
55.         return depthCam;
56.     }
57.  
58.     private float CalculateOrthographicSize()
59.     {
60.         Bounds bounds = GetComponent<MeshFilter>().sharedMesh.bounds;
61.         float maxBoundsSize = Mathf.Max(bounds.size.x, bounds.size.z);
62.         return maxBoundsSize * 0.5f;
63.     }
64. }
65.  
66.  

Code (csharp):

1.  
2.  
3. Shader "Custom/DepthShader" {
4.     SubShader{
5.         Tags { "RenderType" = "Opaque" }
6.         Pass {
7.             CGPROGRAM
8.  
9.             #pragma vertex vert
10.             #pragma fragment frag
11.             #include "UnityCG.cginc"
12.  
13.             struct v2f {
14.                 float4 pos : SV_POSITION;
15.                 float2 depth : TEXCOORD0;
16.             };
17.  
18.             v2f vert(appdata_base v) {
19.                 v2f o;
20.                 o.pos = UnityObjectToClipPos(v.vertex);
21.                 UNITY_TRANSFER_DEPTH(o.depth);
22.                 return o;
23.             }
24.  
25.             half4 frag(v2f i) : SV_Target {
26.                 UNITY_OUTPUT_DEPTH(i.depth);
27.             }
28.             ENDCG
29.         }
30.     }
31. }
32.  
33.  

 

In the end I went with a physics ray casting solution. I created a plane with the same planar bound as my blend and then casted away at the blend to get the resulting 2-dimensional grid I was looking for. All other approaches were to complex or didn't provide the accuracy needed. Now onto the fun part of using this grid of data, first stop creating a map!

The depth based solution I was able to get to work after tweaking the min/max range of the camera depth to get a gradient range.