# How to create a hologram projection with light rays?

I am attempting to make a template for holographic effects in blender for a project I'm working on, however I'm not sure how to create a lighting effect for the projection of the hologram (The god rays and volumetric effect around the globe). Below I have included the blender file along with an example of the type of effect I'm looking to reproduce. Any help would be appreciated.

Edit

With some minor tweaks and modifications I was able to make an effect that looked pretty much exactly as I wanted. Thanks to PGmath, Shady Puck and everyone else for the helpful suggestions and tips.

Final Result:

• Hello and welcome. You have not included the texture, so it is hard to see. Can you indicate a new link for it or upload again your blend file with "pack external data" option ? – lemon Jul 9 '16 at 5:53
• Added the .blend with external data packed – Sookendestroy Jul 9 '16 at 6:19
• I'd use a cone with some volumetric emission and a vertically stretched noise texture driving the strength. The trick would be to get the rays to come from a point instead of going straight up. (I am working on a solution now.) – PGmath Jul 9 '16 at 15:17
• Check my answer here, the technique to create crepuscular rays in the batman symbol also applies to make the holographic symbol blender.stackexchange.com/questions/52884/… – Duarte Farrajota Ramos Jul 9 '16 at 19:12
• How's this? I'll post an answer with it once I polish it up. – PGmath Jul 9 '16 at 20:10

I was able to produce the following result. The planet is all one mesh with complex nodes. The god rays are a separate mesh with a keyframed Vector > Mapping > Location: value. The base is separate as well and uses the setup from How do I create metal materials in Cycles?

## Geometry

The planet is a UV sphere. The "god rays" are a Cone. The steel emitter is a Cylinder with a Bevel modifier and some Edit Mode editing (closing the gap between the beveled edges, adding the depression in the middle, etc.). There is also an Edge Split modifier and a Subdivision Surface modifier in that order, which were added after the Bevel modifier was applied.

Bevel modifier settings:

Current modifier stack:

## Nodes

The following is the nodes for the planet. The leftmost nodes are mostly for mapping and bumping the Image Texture. The leftmost Layer Weight and Math > Add mix adds the Emission ring around the outside of the sphere. The Layer Weight > Facing and ColorRamp add some transparency around the edges. The Wireframe is self-explanatory. The Light Path > Is Shadow Ray takes away most of the object's original too-visible shadow, making it just visible enough.

The following is the nodes for the "god rays." These could probably be improved on a bit. The yellow Vector > Mapping value is obviously keyframed; it's what created the cool shifting effect at the beginning. The small Vector > Mapping > Scale: > Z: value stretches out the Noise Texture to make the rays look more straight. The Light Path > Is Camera Ray makes it a bit more transparent. The Light Path > Is Shadow Ray takes away most of the object's original too-visible shadow, making it just visible enough.

The following is the nodes for the steel emitter. They are better explained in How do I create metal materials in Cycles?

The .blend file:

Edit:

I personally would not recommend any more transparency (mistiness) because you start to lose visible detail. However, if you are dead set on it, you can do one thing.

Before the Wireframe factored shader, add another Mix Shader with the previous and transparency. Add a Noise Texture run through a Bright/Contrast node. This will create a patchy effect.

Nodes:

Test render with new nodes:

As for straight up mist, you would be best to go with volumetrics, but that's not exactly my speciality. You can look at Holographic lighting in Cycles for suggestions, though. There are some pretty good ones.

• Thanks for the very helpful suggestions, this is the end result after following your advice, its pretty close to what I was looking for, except I was hoping for something slightly more misty looking, what would I do if I wanted to give it a sort of falloff effect? i.gyazo.com/dfb181fc8d382ed1158379e693bb32ad.png – Sookendestroy Jul 9 '16 at 19:09
• @user27370 I'll see what I can do later; I'm out now. If my answer helped, please consider accepting it. – Shady Puck Jul 9 '16 at 19:12
• @user27370 edited. – Shady Puck Jul 10 '16 at 13:18
• Some of those node trees are a little hard to see clearly. Would it be possible to pack the nodes a little closer together so you can zoom in more (like I did with mine)? Thanks! – PGmath Jul 11 '16 at 4:29

Here's the result I got:

And here are my nodes:

Note: the Translate and Scale group nodes are homemade equivalents of the corresponding parts of the mapping node. They are explained here. I am using them here because they allow me to plug inputs into the transform values instead of being static like the mapping node is.

The basic idea is to use a noise texture to drive the emission strength of a volumetric emission material on a cone (actually a frustum). The noise texture is scaled up on the z-axis to create the vertical stripes. The real trick is to get the stripes to angle out from a point instead of just going straight up, and that is what all those other nodes are doing. (Sorry for the massive node spaghetti, I had to move them around to get it to all fit on my screen and be readable.)

Here's the basic flow:

1. Start with generated mapping coordinates and scale the z-axis up (smaller scale value) to make the vertical stripes. The Translate node is just to move the origin of the coordinates to the XY center of the object (i.e. center of the base of the object).
2. The Z component of the generated coordinates is extracted to use as a vertical linear gradient to scale the rays in towards the bottom, which has the effect of slanting them out from the base. The RGB Curves node remaps the gradient from 0.0-1.0 to 0.5-1.0, I am using 0.5 because the base of my frustum is one half (0.5) the diameter of the top of the frustum. The Math > Divide node is used to invert the scale factor since we want to scale the texture in instead of the texture coordinates.
3. The resulting mashed-up texture coordinates are used for a noise texture. The color ramp node is used to adjust the contrast of the rays (i.e. make it look more ray-like).
4. To get the rays to fade out vertically instead of coming to an abrupt stop at the top of the mesh I used the generated coordinates z-component gradient again. The RGB Curves node is to reverse the gradient and make adjust the falloff curve. By multiplying it with the rays from the Color Ramp I created the desired falloff.
5. The final Multiply node is to adjust the overall brightness/strength of the rays.

Here is a .blend:

The above .blend contains a couple of enhancements. I set up a very simple armature to make adjusting the size and shape of the beam easier. I set up some drivers in the material so that the scale values are adjusted to match the armature-deformed frustum. It also contains the rest of the above scene.

You can do this easily with a combination of a black and white map image with a brick texture to give you the dots.

• Thanks for the suggestion i'll definitely save that for later, however I moreso meant the lighting effects below and around it rather than the globe itself. Sorry for the confusion. – Sookendestroy Jul 9 '16 at 7:46

The globe can be generated by a simple sphere with a transparent texture on it.

All the other effects (light rays, lens effects, etc) have to be added afterwards in the compositor (or in an external tool like fusion or Photoshop/After Effects). They are no real geometry, they are only 2D textures, that are composed into the scene.

The topic would be to big for a single thread answer. if you need further intel, i suggest you read some general compositing guides.

• Thanks for the info, was hoping to find a way to create a similar effect in 3d. – Sookendestroy Jul 9 '16 at 8:18
• Why not try the light beam effect from the Blender Cloud? cloud.blender.org/p/caminandes-3/56c6da5cc379cf0079716873 Theres a bit of tricky vector math going on to tailor the texture to a cone. Seems like it would be perfect for this use. – 3pointedit Jul 9 '16 at 14:03