Ok I’m new to cycles and working with nodes. I’ve been using blender for years though. I’m trying to figure out how to make a realistic holographic material like, you see in stop signs or reflectors or certain stickers.
I’m thinking that if I project white light on a surface textured in say 3 tone grey scale cubes and set that material to be reflective but only at angles greater than say 30 degrees and then set up a separate color node to break the white reflection of light into its RGB values that I can then use the camera’s vector to vary the color brightness or something.
Read that a few times until you understand what I’m saying. Let me also post a pic of what I’m talking about. I’d really appreciate some direction on this. I may be going about it completely wrong.
You can use multiple mix nodes in combination with the layer weight input node to modulate the colour based on angle. The node tree is a little complicated and i’m sure there would be a simpler way to achieve this using colour ramps - but I have had a bit of a mental block at the moment and can’t think how to do it.
By applying variations of this node tree (i.e. moving the colours around or reversing them for the different areas of text) - you could achieve the effect you are after. Apply this material to a plane - render in live view mode and rotate the plane - you will see the colours changing across the surface based on the angle you are viewing from.
You can easily add a grey channel to this - so that the colours only kick in at a certain angle.
And from an angle (note the plane and the text have different materials. Same node setup - but the colours in the ramp are reversed to give colour contrast between the background and foreground).
Technically a hologram does not emit light - it simply reflects incident light towards the viewer. Of course you probably have to boost the light output of the glossy node so it appears brighter than a straight glossy node would. One way to achieve this is to duplicate the glossy nodes and plug them into the add node as many times as it takes to get the result you are after. Just has a quick play and 4 seems to give a reasonable result.
The colours, number of transitions in the colour ramp, glossy roughness etc can all be tweaked to give a more convincing result - but I believe the node tree below is a reasonable starting point. It may even work better with an anisotropic shader rather than a glossy (edit - which it does - I substituted the glossy nodes in the tree below with anisotropic nodes - and it definitely looks more “holographic”)
Great job! I haven’t tried it out yet. Just say the posts, but looks exactly right. I thought it would be more complicated than this. I didn’t even know what layer weight did. Cycles is such a pain in the ass sometimes. I really wish they’d implement gpu rendering with blender render. I’ll check back when I get a chance to test this out. Thanks a lot!
With the above setup is not possible that the subject recieves light and changes the depth perception. I read there´s a parallax shader occlusion method to this, but I don´t know how could be setup in Cycles.
Any ideas?
Each color gets it’s own anisotropic shader, and the spread of each is controlled by a fresnel with a different IOR. That gives color shift. Although it’s not a true spectral effect, it’s often close enough most of the time.
To have the moving hologram, you could make a separate layer mask for each channel (the grayscale image in a slightly different view), and control the mix of it with layer weight. At least I’d think that’d work. (Still a bit complicated to setup.)
And what box of CrackerJacks does one get certification from? (I’m curious how that works. Is it based on donation money?)
And what box of CrackerJacks does one get certification from? (I’m curious how that works. Is it based on donation money?)