Improve your model
You have a model but think that it could be a bit better, or you've had some issues with your model and need to figure out what to do to fix it. I know that latter feeling, but one word of caution, it is often easier to go back and re-take photos of your model to address most issues, especially went it comes to problems with photo alignment. But still, here are a few suggestion on how a model can be improved.
Improve model shape.
Masking photos might help in creating a better model shape. Your mileage might vary in this step depending on your photos. There are several methods that you can use, here is a list ordered from (in my opinion) the simplest to most complicated
Mask from Model
You can create masks based on the position of photos relative to a mesh. First iteration would be to create a mesh from the sparse point cloud (the point that are used to align the photos), then right click on a photo and select import masks. Use the "from model" method. this will mask out all portions of the model that isn't part of that rough model. This is very fast and can work quite well on simple shapes, but will fail on complicate or intricate models with lots of small detail.
A screenshot of the Import mask interface, showing the options to selection for the mask from model options
Generate Mask GUI
You can use the 'Generate Masks' GUI in the Tools -> Model -> Generate Masks. See this explainer for instructions. There is an option to mask out of focus areas, but this has never worked properly for me.
Remove background using AI
Agisoft provides an official script that uses a python package (rembg) to mask out background in the official Metashape GitHub repository.
Improve texture quality
You'll find that in some cases, a very blurry image was used to create a portion of the texture on your model where you know that there are some much better photos available. You might be familiar with seamline editing when creating Orthomosaic imagery. Unfortunately there is no such option for model textures. Here are a couple of suggestions
Masking blurred portions of image
However, you can try the 'generate Mask GUI' above, or even try a script that I put together . Follow the instruction on that repository.
A screenshot of the detect edges GUI and python script.
Focus stacking
Another option to improve the final outcome is using a focus stacking method. This method has varied results, but I've read that you can achieve reasonable results despite the limitations. If you're interested in this method, I recommend searching for 'focal stacking Metashape' and see if there are any that work for you. I would only recommend this option if you have experience with focus stacking and have a good method to get the photos stacked.
Other improvements
You can improve the way light reflects off of a model and other post processing effects, but these will need to be done outside of Metashape. Check out the next steps!