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Tip: Faking Lighting with the Geometry Node

Tweak lighting within material nodes

One of the worst parts of rendering is the time it takes to get the lighting just right. This can take endless tweaking to get just right and sometimes can be really frustrating. However, in many cases the lighting in the render is close to what you’re looking for, but just needs a few tweaks here and there. Wouldn’t it be nice to just quickly tweak lighting per material rather than the entire scene? As it terms out there’s a node just for this purpose! The geometry node.

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blender_tip_geometry_node_960x540Using the geometry node allows you to adjust the appearance of lighting in your render by blending the colors or materials over each other. While this is not actually changing the lighting direction or intensity, it does allow you to fake the effect and works very well for small changes. This technique works particularly well when adjusting the lighting on a single object, rather than a full scene.

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23 Responses to “Tip: Faking Lighting with the Geometry Node”
  1. Posts: 34
    daddios says:

    An excellent short tip Gleb, more along the same lines would be great. Will put this into practice. Thanks

    • Posts: 519

      Hi Gleb,

      First, thanks for all your videos that are so “to the point”. I love it :)

      I wanted to share a tip with users. You can create the same kind of effects in post production using the Normal pass, RGB separation and Hue&Saturation.
      this will allow you to fake light based on normal of the renderd object.

      I’m recently using this tip in Photoshop and it’s really really good to enphasize details.

      Hope it’s understable and usefull.

      • Posts: 45

        Agree with you, similar tricks could be used in post-pro. For example, using Normality plugin for After Effects.

  2. Posts: 40

    I am stunned at how well this works.

    I assume there’s no form of shadows with this – similar to vertex lighting in older realtime renderers? This means care should be taken if the objects have convex shapes (the example here is, more or less, a ball)

  3. Posts: 45

    Paul, you’re right, there is no raytraced shadows. Direction-based tricks provide an illusion of lighting. If we change overlay color to black we can fake shadows as well, to some degree :). To make illusion even stronger, you can mix 2 or 3 geometry nodes (subtract one direction from the other).

  4. Posts: 235

    That surely is great. More so for the fact that it helps in better understanding some of those nodes like the Geometry one and how they can be mixed to do all sorts of cool things. Looking forward to more advance stuffs.

    By the way, I saw your Drums game demo video, Gleb. It looks really really awesome how they bounce and move so naturally. I´m guessing lots of Rock & Roll video concert research.

    • Posts: 45

      Yeah, that node alone is enough to make a whole lot of direction-based effects. possibilities are endless – it can be paired with vertex colors, procedural noise etc.
      considering drums – really glad you liked the dynamics. maybe physics is a bit exaggerated, compared to real drums. but who knows, how hard one can hit :)
      by the way, lighting on the drums is faked too (using another means, but anyway)

      • Posts: 235

        Well now, that Title Intro with Breakdown is something else man. It looks and feel so cool. Perhaps you can point me in the right direction with something, Gleb.

        I´m currently involved in a project where I need to make a kind of “mathematical view” of nature in a footage. Imagine a Bee flying in to rest on a flower, imagine you see it through Iron Man’s HUD and it displays in real time all the data and mathematical info of the bee’s path and trajectory, it calculates its weight, the flapping of the wings, the movement of the flower when the Bee lands, etc. You know, those cool subtle effects of those info appearing and vanishing as they happen.

        Can Blender do that? should I use After Effects? Ever seen some tutorial where I could grab a trick or two?

    • Posts: 235

      Thanks for the reply Gleb. Those will surely help, that is really close to what I’m looking for, only more subtle.

      I see there are many ways to do this in Blender. I also saw someone do light streaks with a particle system. They decayed over time and it looked like they left a trail behind doing some cool fade out effect.

      I finally found a video on youtube, info-graphic elements, it’s how those seem to be called.

      I’m hoping to get that kind of feel, as if you could see all the mathematics that happens all around, in every movement you make and the data of your every action.

      Thanks again!

  5. Posts: 20

    noob trying to follow along. get stuck on changing mix shader to overlay. my mix shader node has no options on it. where do i find this? intimately familiar with layer options from gimp, so i would love to know how to apply this as a tool.

  6. Posts: 28
    blendernova says:

    Pretty cool tip; although I would be useful when making a game.

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