Drag knife✒️ and Laser🔫 Etched (Specular) Holograms

Some info and resources I stumbled across on Steve Mould’s discord channel and elsewhere while digging into this, including scratchhologram C# code that can load .x3d files, simulate and generate arcs on the view plane…

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OOOOOHHHHH! Who’s gonna try it!?!

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What’s cheapest drag bit you’d try? amzn Diamond spring drag bits seem surprisingly spendy.

2023-02-21 23-54-24_scratch-hologram-preview

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That’s the one i use. I couldn’t really find one cheaper that looked like it worked well. This one did a great job for me on the big acrylic sign i did.

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How many arc segments is that? That seems like a lot. That is so crazy though, I love how things “hide” behind others. Just crazy.

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Lots. Can tune number of points/arcs, GIF shows rough milling time estimates. Guaranteed to be slow. Waiting on diamond bit, sunk enough time into tuning/extending app to rationalize the cost.

2023-02-21 23-54-24_scratch-hologram-vectors

Currently trying to figure out way to remove lines/edges on the same face, have an idea (don’t render edges shared by adjacent faces on the same plane, maybe…). My math isn’t great, and it’s been a while since I coded 3D geometry rendering… Fortunately Mike Miller did all the hard stuff already.

Coded up simple G2 circular arc based script for now. Haven’t looked into tweaking elliptical arcs to reduce distortion, haven’t verified/implemented occlusion. Will share fork if my edits seem more useful than harmful for someone else to use.

2023/2/22 Edit: Model is easier to discern by hiding edges between faces on the same plane. Less arcs, noise and mill time. Fancy drag bit arrived, testing on cheapo bits first…

2023/2/23 Edit: No physical testing yet. Still improving functionality/performance, e.g. arcs for hidden edges/points were mistakenly being drawn. Currently figuring out partial arc segments so occlusion works when changing view angle.

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I am amazed. Cool.

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Hi, can you export SVG or DXF? I can engrave it with laser and i have couple of different methods and styles that can help in evolution of this effects.

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I don’t think a laser would work, It doesn’t leave a shiny scratch, and I would think the mark it would make would be too large.

Are you sure ? Because i know what I’m telling :sweat_smile:
Here couple examples of my works on Instagram @rokolart.lviv
And here some gif

ac66b0aa-adef-4380-9e5c-e281208be422

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I found a lot of effects, so I think it’s be useful for you to understand what possibilities there.
c5f89de8-c611-4c1c-b4b2-b00759bf05c7

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I didn’t even think about metal. That would be nice! Please share an example when you get it working!

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Hello @Ic_In, welcome! You’re creating beautiful work pieces on https://www.instagram.com/rokolart.lviv/. Just posted a reference to this forum on Steve Mould’s Discord incase others are interested.

The things you’re doing with laser etching look like sorcery to me. We have a bunch of laser folks here too. Look forward to learning how you guys are lasering color finishes from their metal stock?

Not yet, but maybe, SVG should be very doable (have written code to generate that before), will take a look if I can figure out occlusion, and speed things up.

I reached out to Mike Miller via github to thank him for sharing the project, and let him know it’s being tinkered with here.

Will keep sharing occasional updates partly for anyone who’s interested, but also partly to help discover if others have done this already (so I don’t need to :slight_smile: ), and/or discover interesting related work out there. Cheers!

Nice additions to the original program! I’d love to take a look at your fork, and use the gcode export to do some practical testing on a few different materials i’ve ordered, if you’re able to publish it.

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I’m also trying to make some research with rhino7 grasshopper to generate geometry easy, but looks like it takes too long, so will be happy to see your examples and test them.

Thanks for your time. Cheers

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Figured out how to implement occlusion (renders partial arc segments instead of full 180degrees). Working on SVG export, performance and cleaning up (much hackery…) before pushing to my fork/repo.

Removing GCODE export for now, was personally OK with spitting out GCODE for personal consumption. However… I don’t want bugs/incorrect-usage to damage people’s machines and/or $$$ diamond bits.

Since we’re working with 3D models, I took the liberty of experimenting with V1 to symbolically represent V1 machines. The Nozzle is meh, was meant to look more V like, was quick 10 min Fusion 360 3D hack job, mainly just to be a proof of concept, hope it’s not offensive, happy to remove or use something better?

2023-02-25_v1e_logo_symbols_arc_segs

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A smaller extruded v1 logo only?

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With respect to lasers, I ran a quick test this morning. I painted over foil, then lasered a pattern (which removed the paint).

If these lines were hand scribed in plexiglass, they would produce a hologram of a line, which would rotate as the angle of the plexiglass wrt the light is changed.

As for my experiment, it did not work. The reason is that the effect depends on the groove in the surface. Removing the surface coating does not produce the same sharp highlights as a physical groove in plexiglass. It is possible it would work if an IR or fiber laser was used so the metal is physically scribed as part of the engraved, but even then, I’m not sure the shape of groove would be right to catch the light.

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Good to see your tests.
Yeah, you maybe right, we should stop trying to make this with laser, there a lot of impossible, so i hope to see how will looks result with physical scratching and arc generator.

Upd.
Found old test with plexiglass and laser engraved design.

fe1ac489-2e69-44d9-9798-7ef3e1768406

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I would love for lasers to work, and if anyone on this forum has an IR laser, I’d love to see whether my pattern engraved in the metal would produce a line hologram effect. The pattern is about 35mm across.

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