[Feature] support visualising meshes in just one hemisphere.

[alessandrofelder]

Is your feature request related to a problem? Please describe.
Showing the mesh in just one hemisphere is a common use case.

Describe the solution you'd like
Being able to do the above through the GUI

Describe alternatives you've considered
Pre-compute hemi-meshes and provide them through the atlas API. Would make download slower though.

Additional context
Discussed on a forum post

[imagesc-bot]

This issue has been mentioned on Image.sc Forum. There might be relevant details there:

https://forum.image.sc/t/brainrender-napari-change-mesh-color-and-display/96798/8

[adamltyson]

napari-vedo-bridge could be useful? Especially because the example in the readme is cutting a mouse brain mesh to get a single hemisphere 😆