Steps to create textured mesh from point cloud using Meshlab

TexturedMeshSteps.md

Steps to create Textured Mesh from Point Cloud using Meshlab

Get your PointCloud into MeshLab

• Import the pointcloud file in ".ply" file format in Meshlab. Before importing make sure you do some pre-processing / cleaning on point cloud so as to ease the process of meshing.

Point Cloud Simplification and Normals Computation

• Next we need to reduce the number of point samples for smooth meshing.
  • So go to Filters -> Point Set -> Point Cloud Simplification. Enter Number of samples circa 5% of original number of points. Make sure Best Sample Heuristic is checked.
• After point cloud simplification, make sure to select Simplified point cloud in the Show Layer Dialog on the right hand side. If not visible, it can be opened by navigating to View -> Show Layer Dialog. Now we need to compute normals for point set.
  • So go to Filters -> Point Set -> Compute normals for point sets . Enter Neighbour num between 10 - 100. Initially try with 10 and try to get a mesh and later see if this can be improved by increasing the neighbour number. For Smooth Iteration initially try with 0 value and may be later it can be tried with values between 5 - 10. I mostly use value 8.
• Make sure if your normals are properly computed by going to Render -> Show Normal.

Meshing / Poisson Surface Reconstruction

• Next we are going to use Poisson Surface reconstruction to do meshing.
  • So go to Filters ->Remeshing, Simplification and Reconstruction -> Screened Poisson Surface Reconstruction. Initially try with default parameters then later one can play around with reconstruction depth, number of samples and interpolation weight values.
  • This will create another mesh layer called Poisson in the Show layer Dialog which has surfaces now. Make sure to select that to peform further operations.
  • One can observe that it has also created some extra surfaces. To remove them go to Filters -> Selection -> Select Faces with edges longer than .... By default the value is automatically computed, just click on apply. Then click on delete face button (triangle face and three vertex with a cross over it). This will remove extra surfaces.
  • After this operation, still some noise faces can be seen. To remove them go to Filters -> Cleaning and Repairing -> Remove isolated pieces (wrt Face Num.). Use the default value and make sure Remove unreferenced vertices is checked. This will remove some noise faces.
  • Even after the above operation some noise faces are seen. To remove them go to Filters -> Selection -> Select non Manifold Vertices. Click apply. Then click on delete face button (triangle and threwe vertex with a cross over it). This will remove remaining extra faces.

Texturizing the Mesh using pointcloud color attributes.

• Now that we have a mesh, next step is to get the texture for the mesh from the pointcloud.

• Make sure to select Poisson in the Show layer Dialog to peform further operations.

• Go to Filters -> Texture -> Per Vertex Texture Function. Click on apply.

• Go to Filters -> Texture -> Convert PerVertex UV into PerWedge UV. Click on apply.

• Go to Filters -> Texture -> Parametrization: trivial Per-triangle.

  • Quads -per -line : 0
  • Texture Dimension (px) : 4096 or (1024, 2048).
  • Inter-triangle border (px) : 0
  • Method : Basic (with Space-optimizing somethimes Meshlab crashes.)
  • Click on Apply.

• Now go to File -> Save Project As... Save the project in ".mlp" file format.

• Now go to File -> Export Mesh As... Save the mesh in ".obj" file format. After clicking on save, it will open saving options. Make sure under Wedge, TexCoord is checked. Then click on OK.

• Now go to Filters -> Texture -> Transfer: Vertex Color to Texture.

  • Texture file : (If your mesh was saved as mesh_1.obj, the texture file name should be mesh_1.png)
  • Texture width (px) : 4096 (make sure this is same as Texture Dimension in the above steps)
  • Texture height (px) : 4096 (make sure this is same as Texture Dimension in the above steps)
  • Check Assign texture and Fill texture.
  • Click on Apply.

• Now you have a textured mesh. There is also a texture image file saved in the same directory where original mesh was saved.

• If originally you saved your mesh as mesh_1.obj, after the above operation it will create mesh_1.obj.mtl and mesh_1.png. These are the three files needed to view textured mesh on any ".obj" file viewing software like Blender or autodesk etc.

Initially I couldn't find any proper step-by-step process to create textured mesh on meshlab. I hope these steps help people to come up with their own textured mesh. :D

If something is not clear, don't hesistate to comment on this.

Cheers!