Creating 3D Models for QGIS with ODM on Windows ¶

This walkthrough demonstrates how to generate 3D models using ODM and Blender from video frames captured on a cellphone, then utilize the 3D model as a symbol within QGIS.

Blender is described as “a free and open-source 3D creation suite.” Open Drone Map (ODM) functions as “drone mapping software that can be used to generate 3D models from aerial images” and similarly works with cellphone video. This post adapts guidance from Tim Sutton’s Linux-focused tutorial.

Required Software ¶

• ffmpeg
• ImageMagick
• Blender
• QGIS
• WebODM or ODM command line toolkit

Configuring ffmpeg ¶

Download the executable from FFmpeg-Builds repository. Unzip and add the directory path to your System environment variables.

Configuring ImageMagick ¶

Rename the ImageMagick convert.exe file (e.g., to im-convert.exe) to avoid conflicts.

Configuring WebODM ¶

WebODM serves as a web interface and API to OpenDroneMap. Install manually via GitHub repository following the provided README instructions.

Configuring ODM Command Line ¶

The ODM toolkit requires Docker installation. Reference the ODM Quickstart guide for implementation details.

Extract Video Frames ¶

Create a working directory and place your video file inside. When recording, ensure “the entire object fits in the video frame throughout the video.”

Use ffmpeg to extract frames:

ffmpeg.exe -i FlowerPotVideo.mp4 -vf fps=1 -f image2 image-%07d.png

Generate an animated GIF using ImageMagick:

im-convert.exe *.PNG FlowerPot.gif
im-convert.exe FlowerPot.gif -scale 25% FlowerPotSmall.gif

ODM Processing ¶

Option One: WebODM ¶

1. Create a new project using the Add project button
2. Upload the .png images into WebODM
3. Run processing with default settings

Option Two: ODM Command Line ¶

Organize images in a subfolder structure:

FlowerPot
├── images
│   ├── image-0000001.png
│   ├── image-0000002.png
[... additional frames ...]
└── FlowerPotVideo.mp4

Execute the Docker command:

docker run -ti --rm -v "pwd":/datasets opendronemap/odm --project-path /datasets FlowerPot

Blender Workflow ¶

Download textured model assets from WebODM processing. The relevant file is textured_model/odm_textured_model_geo.obj or odm_texturing/odm_textured_model_geo.obj (depending on processing method).

Launch Blender, create a new General project, delete the default cube, and import the OBJ file. Enable Viewport Shading mode to visualize the loaded model.

Correcting Model Orientation ¶

Use the Transform panel to adjust position, rotation, and properties numerically, or employ keyboard shortcuts:

• G = translate
• S = scale
• R = rotate
• X, Y, Z = constrain to axes

Removing Unwanted Objects: Method 1 ¶

Enter Edit mode, select all geometry (A key), right-click, choose ’loose parts’. Return to object mode and iteratively delete unwanted components.

Removing Unwanted Objects: Method 2 ¶

In Edit mode, deselect all. Select vertices/faces to remove, press X, choose Vertices from the context menu.

Removing Unwanted Objects: Method 3 (Bisect Tool) ¶

This method is “the simplest method to work with.” Select all geometry (A), access the Bisect tool from the Knife tool dropdown. Draw a bisecting line, then choose Clear Inner or Clear Outer to delete unwanted sections. Repeat until only your model remains.

Model Simplification ¶

To prevent QGIS from becoming unresponsive, decimate geometry to reduce vertex count while preserving shape. Aim to reduce complexity to “10% to 15% of the original.”

Export the cleaned model as a new OBJ file in the same folder as textures.

Integrating into QGIS ¶

Create a new QGIS project using OpenStreetMap XYZ layer with EPSG:3857 CRS. Create a scratch point layer with Z values, zoom to your object’s location, and place a point marker.

Add a 3D map view to your project. In point layer properties, disable 2D symbology and set 3D symbology to use your OBJ object file.

Navigate to your model in the 3D map view to visualize the real-world 3D model within QGIS.