Timeline for Simulating neon: Find angle between two vectors with shader nodes
Current License: CC BY-SA 4.0
8 events
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| Sep 23, 2021 at 6:48 | comment | added | Robin Betts♦ | Ahhh.. so sorry, missed your conversion! (I've just slapped my own wrist.) For both of us, since the object is to keep the illusion of a brightness in the middle of a volume, it's lucky that neon tubes are cylindrical :D | |
| Sep 23, 2021 at 0:00 | comment | added | NeverConvex |
Yeah, definitely view-dependent; the View Vector is converted into World space so it isn't expressed in the basis used in Camera space, but the effect will still vary as the view is moved around, of course. I think that's a property it shares with Fresnel (just from playing around with the Fresnel node a bit in Blender), and with Facing too (the 'light' regions seem to turn towards me as I rotate around a target object)? If imposing the effect from a fixed angle were desired, it would be easy enough to replace the View Vector with some user-specified vector of choice, though
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| Sep 22, 2021 at 14:11 | comment | added | Robin Betts♦ |
Also.. the View Vector is in Camera space, where the Geometry > Normal is in World space, so you would expect the effect to be view-dependent..
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| Sep 22, 2021 at 12:10 | comment | added | NeverConvex |
I think that's a good point; arccos is only really needed if you want to think in rads or in degrees. It also ensures you know the range of inputs to pass into the Map Range node, but I think (c \dot n) / (||c|| ||n||) should already live in [-1,1], so you could probably optimize it a bit by deleting the middle Frame and entirely and connecting the first Frame output directly to the Color Ramp, like you're saying, I think
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| Sep 22, 2021 at 10:22 | comment | added | Robin Betts♦ |
Nice. +1. I do wonder though, whether the expensive arccos is worth it, since the result goes through a fairly arbitrary Color Ramp anyway, and the whole remapping from dot-product could be done in there? Maybe I'm missing something..
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| Sep 22, 2021 at 0:54 | history | edited | NeverConvex | CC BY-SA 4.0 |
added 83 characters in body
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| Sep 22, 2021 at 0:43 | history | edited | NeverConvex | CC BY-SA 4.0 |
added 153 characters in body
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| Sep 22, 2021 at 0:38 | history | answered | NeverConvex | CC BY-SA 4.0 |