My experiences were full of obstacles as well. So I’m thinking of making a course to show how to deal with issues.
In long:
Making the UV mapping is complex. I make often bug reports isolating each issue
https://mcneel.myjetbrains.com/youtrack/search/Reported%20by%20me-665#issueId=BO-2982
I use RizomUV Real Space as a helper to understand what is happening with the UV mapping.
I make the Unwrap in Rhino and cheche in RizomUV Real Space the UVs because can conserve Rhino vertex normals. But my actual problem is that Rhino export multiple unwelded meshes of what it looks like (in Rhino) a single merge polymesh. I can’t use external tools to make a proper UV mapping. And I hope that @Jussi_Aaltonen (that looks like working hard on all of my bug reports) will fix this bug one day.
I do not tile the texture anymore going out the UV space. I use to do that but later baking shadows is not possible because of the overlapping of UVs. I never overlap UV. I try to fit the UV mapping into the 1:1 space without repeating.
At first, as a beginner, when making, for example, repetitive wall patterns (architectural), we tend to use more than the 1:1 UV space. When we became more expert we try to avoid that (we stay inside 1:1 space), especially if is an Industrial design object for real-time rendering. Overlapping UV projection creates issues. Going outside only if you are rushing is a compromise.
With a Designer, you can build complex meshes that will be displayed inside your Rhino mesh or surface using the computational expensive tessellation displacement high map texture.
example: https://www.youtube.com/watch?v=eodc61SCglE
Substance Designer was the very first product for making complex textures to a node base.
Then I use Substance Painter ( suggest indie perpetual license in steam if you want to use only Painter and Designer) that is an evolution of Designer. Making nodes is time-consuming so I prefer Painter over Designer. Making nodes is useful for creating mesh tessellation but you can do that also in Painter by painting. I use photo textures. In Painter use photos as the source. Then I export the final textures to Rhino or else for rendering.
For real-time visualization to the client, I use in order of complexity Painter (via Iray that is included), Rhinoceros 7 new rendering, Unity HDRP VR in future Unreal 5, and complex rendering Octane. Other options are too expensive from my point of view.
Here are the results of my work mostly done in Rhino RizomUV and Painter :
https://www.artstation.com/mattano
And a project that I’m working on right now:
