How to re-organise messy uvs on texture image I have imported a glTF model of coral reef. It is good but has a huge polycount. I have a created a low poly copy but when I look at the uvs and texture image of the high poly import the uvs on the texture image are disjointed.

This is the high poly model



This is the image texture for that model


If I want to change the colour or quality of a portion of the model, it is almost impossible to do it because the uvs are not organised together to make changes to the image texture easy (in an external photo editor)

Say I want to change this portion of the model

the corresponding uvs are arranged in the image like this


Is there a workflow that will re-arrange the uvs more stragetically so I can make improvements to the quality of the image and then apply it to the low poly mesh.

many thanks

RichardC

*****UPDATE*****

I have found an acceptable solution, particularly based on Arthur's advise below. 

I baked the texture image from the high poly to the low poly mesh. The secret is to UV unwrap 'Projected from View' having positioned the high poly mesh at the correct perspective/angle. The results as follows.

The low poly model in object view (right) and the new image baked from the high poly mesh:



The low poly model in edit mode with vertices selected (right) and those vertices shown on the new texture image (left).

This now makes alteration in a specific area of the image easier to identify in an external photo editor.
It won't get any better than that. This mesh is complex with a lot of small details. So either UVs will be stretched either they will be disjointed. In this case, it is usual to paint directly on a mesh and not on the UV islands.





There are some solutions. Paid or not. This particular one is not ready, but it is about Blender: https://www.youtube.com/watch?v=PLUoLQUK3-s Usually this stuff is done manually, which won't pay off in this case. I suggest to leave it as it is.