Hi,
Sorry, but I can’t reproduce it reliably. The error just occurs at random, but - as for now - only when I use somewhat complex material functions (like this multilayered bump offset or a triplanar mapping function) or when I “ctrl+c, ctrl+v” a bunch of nodes from one material/function into another.
Nonetheless, I’ve created an example project that contains this bump offset function as well as a material and another function that make use of it. It’s only 55 MB, so I’ve uploaded it via Google Drive:
https://drive.google.com/file/d/0Bx4368z9Q6hFSENNOXlOS0NndEk/view?usp=sharing
Since I can work around it most of the time it’s not very urgent, but it can be a little bit annoying to wire up a complex material for several minutes and then not being able to save it.^^
Thanks in advance!
Julius Weber
Ps: Btw, is there any special place where one can suggest new features for the engine?