As i understand it , normal mapping has to be done with a normal texture ( those purplelish ones ) set to non color data and also using a normal map node…
then there is the displacement input on the material output…
how is this properly used ? doe it also needs a normal texture? black and white? how is the result different that normal mapping because to me it doesnt move or displace geometry but just seems to play with shadows to create the effect of more geometry…
I am by far not an expert at this, for I sometimes wonder myself. I do know that a normal map does not displace geometry or even appear to displace it. That, I believe, is what a voxel map does. A normal map is like a bump map in the fact that it makes the illusion of depth. It is different from a bump map because it also gives information to the light and shadow rays to make it look like shadows and highlights are falling into that depth. Perfect example is place a bump map on a plane and look at it at a low angle. It will look smooth even though you can see that illusion of depth. Now place the normal map on that same plane and it won’t look smooth anymore, but like you have geometry for all that depth in there.
Now, from what I’ve read and understood (which is probably wrong), is that the displacement socket can only give you bump map results and the normal sockets can give you either depending on the image you plug into it.
For your other question, a bump map is usually a black and white image with white being highest points (value of 1) and black being the lowest (value of 0). That being said, a bump (displacement socket) can use any image to create that illusion. All it does is take the color values and use that for depth.
Hope this helped a little. Sorry for the kindergarten explanation, but I’m not as learned on the subject as I should be. One who knows this very well is Sebastian Konig if you can get ahold of him.
I had exactly the same doubts today, so I made this little comparision. Test setup is pretty straightforward, Blender 2.69, Cycles, scene with one plane and sun as source of light. Texture which I used is some rocks picture from google images. Normal map, specular/glossy and ambient occlusion were generated by “Insane” plugin for Gimp.
Results are interesting and it looks to me like Andrew was wrong in his “The Secrets of Realistic Texturing in Blender” tutorial.
First ever response to thread so be kind:
I have seen the Andrew Price tutorial and as I remember it, the Normal, Spec and diffuse maps generated by Crazybump and the like are used in the node editor but the displacement map is applied to mesh by subdividing and then applying a Displace modifier.
Hope this helps in some way.
4 images used; last one is if you want to use displacement modifier - looks what would be hightmap.
Cycles Experimental render mode can take advantage of Output node’s Displacement information; Supported mode has effect to the bare minimum (it used to be much more responsive IIRC). To do this i needed to switch on True on Object data tab Displacement and subdivide a bit the mesh. There is checkbox Use Subdivision which one time took advantage of Subdiv mod - right now object turns pitch black. Any sudden moves with these might cause to lock blender. Do not switch while something renders. If you change strength of the displacement switch to Solid mode, then back to Rendered otherwise changes are not seen. YMMW. http://www.pasteall.org/blend/25393
if you download the images for re dong nodes set up it does not work
you need to uplado image in Gimp then re save all images
or it will render as a mauve plane !
