Any time I try to drag the tangent input into the left side of a nodegroup to create an input it causes a hard lockup on my PC, requiring a hard restart. Am I alone here?
– Doctor, it hurts everywhere I touch…
– Your finger is broken.
More seriously… Which version of Blender? Where do you pull that tangent input from? I tried with the Anisotropic shader in 2.66+. Nothing special happened. Is your group connected to the Surface socket when you do that? I noticed once that some bogus value was fed to the vector input socket of a node group I made but it wasn’t a Tangent vector. If it happens and Blender tries to render the preview, it may lead to a strange result, even worse. Well, if your version has Cycles material preview and if it uses the GPU…
Details! Help yourself in helping as much as possible those to whom you ask questions, Little Grasshopper.
it was indeed that it was trying to load a false value during preview render. Thanks for the help!