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Importing an .OBJ file with textures from Meshroom into ZBrush

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#1

I am trying to import an .OBJ file with texturing generated by Meshroom 2019.2 into ZBrush 2020.1.3 while keeping colors., but the coloring / texture won’t show up automatically.

The .OBJ I’m trying to import is a huge photogrammetry reconstruction (282MB) with 17 texture .PNG and one .MTL file.

I can’t find instructions to apply the many texture files accompanying the huge landscape .OBJ file once imported into ZBrush.

How can I either

  1. manually import the 17 .PNG texture files accompanying the OBJ to display the landscape colors, or
  2. use Meshlab as an intermediate step to convert the original OBJ file and accompanying texture files to a single .OBJ (or any other format contaning the color information).
  3. use any other pipeline

Skanect Pro, another software for scanning outputs single OBJ files with integrated colors that play very well with the ZBrush Tool / import OBJ function. Also, Meshlab and Meshmixer both display the .OBJ with colors properly.

I am sure there is an easy way around this problem, such as a plugin, or a simple file conversion to do in Meshlab in order to render it compatible with ZBrush.

Your expert help would be appreciated.

#2

Here’s the answer to my question.

To easily import a textured Meshroom 2019.2 reconstruction ( .OBJ file with accompanying .MTL and .PNG files) into ZBrush 2020.1.3, the .OBJ file needs to have Vertex Color information embeded in the .OBJ file.

Process.

  1. Perform reconstruction in Meshroom
    The OBJ reconstruction with texture maps are located in the MeshroomCache/Texturing folder of the project.

  2. Use Meshlab 2020.07 to convert the color information from the texture map into vertex coloring.
    Meshlab:

  • Filters menu / Color Creation and Processing / Transfert Color: Texture to Vertex / Apply
    In the purple information bar at the bottom of the screen, VC (for Vertex Coloring) will appear under the mesh information.

  • File / Export Mesh As … / Alias Wavefront Object ( *.obj).
    “Choose Saving Options” pop-up dialog box: under Vert / Face / Wedge, make sure ONLY Color and Normal are selected (uncheck all other options). Ok.
    This will generate a single .OBJ file with color information per vertex, a format readable by ZBrush without plugins or manually applying complex texture maps to a mesh.

  1. ZBrush 2020.1.3: Tool / import. Select the OBJ file converted in Meshlab. The mesh with coloring information is automatically imported.
#3

Hello @Plastified

Be sure to update your software to the most up to date version of the program–currently 2014.1.4. This is free for registered users, and obsolete versions are not supported.

To apply a color texture in ZBrush, you must first import it into the program, then activate it in the Texture Map menu. Be aware that ZBrush doesn’t function like other rendering engines you may be familiar with. Only one texture can be active at a time, and Zbrush does not render texture detail by layering image maps the way some programs do. Advanced rendering in Zbrush is often the result of a multiple render pass compositing workflow.