Mesh Preprocess with Convenient Interface

This is a tool with convenient interface to align mesh to specified coordinate system, handling displacement transformations and dimensional conversion.

Enviornment Setup

Create a conda virtual env is recommended. And download some packages which are required.

git clone https://github.com/chenhengwei1999/mesh-preprocess.git
cd mesh-preprocess
pip install -r requirements.txt

Usage Guide

Mesh Alignment

Until now, this repo implemented alignment function for mesh translation, mesh rotation, and mesh dimensional conversion.

Firstly, check the parameters that can be used.

python src/mesh_align.py --help

The terminal will output the following information.

usage: mesh_align.py [-h] [--yaml_path YAML_PATH] [--vehicle_meshes_root_dir VEHICLE_MESHES_ROOT_DIR] [--vehicle_yaml_name VEHICLE_YAML_NAME] [--suffix SUFFIX]

Batch Mesh Align

optional arguments:
  -h, --help            show this help message and exit
  --yaml_path YAML_PATH
                        The path of the yaml file
  --vehicle_meshes_root_dir VEHICLE_MESHES_ROOT_DIR
                        The root directory of the vehicle meshes
  --vehicle_yaml_name VEHICLE_YAML_NAME
                        The name of vehicle mesh in yaml file
  --suffix SUFFIX       The suffix of the mesh file

• yaml_path: The path of the yaml file. This file contains information on how all meshes need to be processed, such as rotation angle, size scaling ratio, sub folder name, etc.

• vehicle_meshes_root_dir: The root directory of the vehicle meshes.

• vehicle_yaml_name: The name of the vehicle mesh when reading from the yaml file is only used to distinguish different meshes.

• suffix: The suffix for mesh files currently only supports .obj format files.

Code Tutorial

Assuming you have many vehicle meshes saved in folder ~/Documents/mesh-preprocess, there are many meshes under this root directory, and the directory structure refers to the following tree structure:

# ~/Documents/mesh-preprocess
.
├── ford-mustang
│   └── mustang.obj
├── sport_car_3.obj
└── sport_car.obj

There are two things you need to do. Firstly, you need to define the parameters for processing the mesh in params/mesh_align_params.yaml, such as:

VEHICLE_3:
  subfolder: "25-ford-mustang"
  name: "mustang"
  # whether needs to be rotated, angles (not radian)
  rotate_angle: [0.0, 0.0, 90.0]
  # whether needs to be scaled
  scale: false
  scale_factor: 0.1

Among them, subfolder corresponds to the sub root directory name of the corresponding mesh, name refers to the file name, rotate_angle is a list containing 3 floating-point numbers, scale represents whether to scale, and scale_factor is the corresponding scaling ratio.

Secondly, adjust rotate_angle based on the visualized results with trimesh, and then adjust scale_factor based on the output of the terminal (colored logs).

Here is a simple example of terminal usage.

cd mesh-preprocess/
python src/mesh_align.py --vehicle_yaml VEHICLE_1

Tip: In the visualization interface, the following keyboard buttons can be used to switch display effects.

• mouse click + drag rotates the view

• ctl + mouse click + drag pans the view

• mouse wheel zooms

• z returns to the base view

• w toggles wireframe mode

• c toggles backface culling

• g toggles an XY grid with Z set to lowest point

• a toggles an XYZ-RGB axis marker between: off, at world frame, or at every frame and world, and at every frame

• f toggles between fullscreen and windowed mode

• m maximizes the window

• q closes the window

Finally, the aligned file will be saved in the root directory corresponding to the mesh file.

Reference

• Trimesh Documentation