Export u3d in a container?

[ghost]

Hello PyMeshLab Team!

What do you think it would take to be able to use pymeshlab inside a container spawned from the latest ubuntu image (or something like that). Is this possible? I am currently attempting to do it with xvfb but would appreciate any suggestions.

Thanks!

[alemuntoni]

Hi @bdf-imbio!
I am not really into containers, but if python and numpy can be installed, then it should work.
As far as I know, github actions works with containers, and all the tests are run on it!
Are you experiencing issues?

[alemuntoni]

Yes, that repo you linked is the same that meshlab uses, with some modifications.
This u3d exporter it's a huge mess. Unlike any other reasonable library, the IFX libraries are not loaded using the linker, but are loaded internally in the C++ code of the converter. This makes impossible to change anything in the library, and it is very easy to break something.
The only way to understand what's going on is to debug the code and look which library is failing to be loaded (and try to understand why).

I know that the u3d exporter is a very appealing feature of meshlab, but managing this library is very painful, and unfortunately there are no alternatives.

[alemuntoni]

Moreover, loading a library internally in the C++ code, means that the starting directory where the search of the library is performed, is the same of the binary that is being executed. That binary, in the pymeshlab case, is the call of python... Which may be literally anywhere in the system. That's why in pymeshlab the exporter is not working.
I am sorry that the u3d exporter does not work, but fixing this would take a lot of time that I just don't have right now. I'll fix this whenever it will be possible, but I can't make any promise at the moment :(

[ghost]

Thanks for explaining all that. I understand you are super busy so I really appreciate the time you've taken to walk me through this stuff. Whenever you do get around to making the u3d export work, I have a project for it :)

[Sea421]

Hi @bdf-imbio,

I have faced with same issue. Please visit the discussion.
In my case it was locale issue. May it help

[alemuntoni]

u3d exporter now works fine in PyMeshLab! :)
The fix will be available in the next releases!

[ghost]

It is possible to export u3d files with pymeshlab in a container but it requires installing the IDTFConverter tool manually.

Here is a Dockerfile with the requisite dependencies and steps:

FROM ubuntu

# install pymeshlab dependencies
# noninteractive frontend required to install tzdata w/out input
RUN apt update && DEBIAN_FRONTEND=noninteractive apt install --yes \
    python3 \
    python3-pip \
    libgl1-mesa-dev \
    tzdata \
    libglib2.0-0
# install pymeshlab
RUN pip3 install pymeshlab

# install IDTFConverter
# dependencies
RUN apt update && apt install --yes \
    build-essential \
    git \
    libpng-dev \
    libjpeg-dev \
    locales
# set local to en_US.UTF-8 (IDTFConverter expects this)
RUN sed -i '/en_US.UTF-8/s/^# //g' /etc/locale.gen && locale-gen
# clone u3d repo
RUN git clone https://github.com/ningfei/u3d.git /tmp/u3d
# build
WORKDIR /tmp/u3d
RUN ./configure && make && make install

WORKDIR /root/input

Build an image from the Dockerfile with docker build -t u3d_exporter . from the directory containing the Dockerfile.

Spawn a container from said image with docker run -it --rm -v /path/to/your/meshes:/root/input u3d_exporter where the -v option allows you to share your local meshes with the container.

From the container prompt, launch python3, import pymeshlab and export to u3d:

import pymeshlab as ml
ms = ml.MeshSet()
ms.load_new_mesh('your.mesh')
...
ms.save_current_mesh('your_mesh.u3d')

You should now have a u3d file you can use to with a 3Dpdf. For questions concerning a specific step or tool, please consult the relevant documentation.

Thanks to @Sea421 for figuring out the locale issue that was breaking the IDTFConverter.

Note that at this time, color u3d output is not possible, likely related to #42.

Also, at some point the steps above related to installing the IDTFConverter maybe become irrelevant when pymeshlab is fixed to do the conversion itself, see #27.