If you need to create the complete model (360-degree model) of an object, we can suggest processing all the images in a single chunk to provide better accuracy and quality of the final results, compared to the chunking method (separate processing of the sub-sets of the complete image set and merging them together).
We recommend splitting the images into different calibration groups in the ONE chunk and aligning images together. Follow these steps:
1. Select Add Folder or Add Photos command from the Workflow menu.
2. After the images have been added, select the images to be combined in the Workspace pane and select Moves Cameras > New Camera Group from the context menu, repeat this step for all groups of photos.
To get proper reconstruction results in the single chunk it is necessary to apply Masks to all images in order to cover the background (otherwise it will introduce false tie points and would affect the alignment).
If you following the turntable image acquisition scenario when the camera position is fixed and the object is being rotated in front of it, you can automate the process of the masking by using "background" masking approach: for each different camera location compared to the static background take an image of the background without the object. Some additional details regarding the background masking can be found in the following article - Masking from background.
1. After the background is masked on every image in the set, select Align Photos from the Workflow menu.
2. Set the following recommended values for the parameters in the Align Photos dialog:
3. Click OK button to start photo alignment.
If you need only 3D model, you can skip the step of building a Dense Point Cloud and going to the step of building a Mesh.
Build Dense Point Cloud
1. Select Build Dense Cloud command from the Workflow menu. Set the following recommended values for the parameters in the Build Dense Cloud dialog:
You can filter out the noise of a dense point cloud using the parameter "Calculate point confidence"
2. Click OK button.
1. Select Build Mesh command from the Workflow menu. Set the following recommended values for the parameters in the Build Mesh dialog:
If building Dense Cloud, we recommend using the parameter - Reuse depth maps.
2. Click OK button to start building geometry.
1. Select Build Texture command from the Workflow menu. Set the following recommended values for the parameters in the Build Texture dialog:
2. Click OK button to start building texture.
If you still processed photos in different chunks:
It is worth noting that if the images are not georeferenced, then prior to align images of the second chunk, place common markers (by measuring markers on one model, exporting them and then importing markers into the second project. Measure markers on the images and then align the images).
To merge chunks:
1. If the images are georeferenced then you need to select Merge Chunks command from the Workflow menu.
2. In the Merge Chunks dialog box select chunks to be merged and the desired merging options. Click OK button when done.
3. Metashape will merge the separate chunks into one. The merged chunk will be displayed in the project content list on Workspace pane.
Chunks merging results (i.e. photos, point clouds, and geometry) will be stored in the new chunk and it may be treated as an ordinary chunk (e.g. the model can be textured and/or exported).