Simulating black-and-white gradients in 3D printing using structural patterns: tips on technique and dimensions.
Hi everyone,I'm working on a flat 3D printing project (0.5-1 cm total) measuring approximately L 20x h 25 cm. I need to create an image with two main colors:a black base (printed directly)and a white top layer, which I want to hand-paint with UV-reactive acrylic paint.
The problem is that the original image has soft transitions between black and white, with soft shadows and grayscale, but I can't achieve these nuances with printing because the white will be added manually(because i need a uv reactive color, not possible to make a shades)
So I'd like to simulate the gradient not with color, but with the geometric structure of the white layer, using a variable-density pattern (like halftone or dithering) made of small bumps or holes that visually modulate the amount of white present, creating a gradient effect.
Some challenges:
- I'd have a print shop print (I don't have precise printer data), so patterns that are too small might not print well or might break.
- I need to figure out how to size the pattern (minimum size, spacing) to achieve a good balance between detail and robustness.
Does anyone have experience with this type of effect in 3D printing?
How did you manage to create the gradient transitions using geometry?
If you have better alternatives to this logic, please feel free to suggest them.
I also reproduced the four layers in Adobe Illustrator because I initially thought I'd use them to make molds for epoxy resin. If I were using resin, I might use more or less pigment to reduce UV reactivity.
Thank you very much to anyone who responds.
I've attached an image to give you an idea.
RE:
The size of it is 20x25cm?
Frankly speaking I would forget about the 3d printing it, no matter the size.
The best option would be to do the opposite - use white glowing background and cover it with black paint, using screen printing, which is very common when doing t-shirt logos https://en.wikipedia.org/wiki/Screen_printing - you could export each layer as a different color or use dithering to get the shades.
The problem with the 3d print is really low resolutions so you will not get the details you would expect to have, to the point it will look like a poor quality print.
If you need the print withstand the weather conditions you could just use proper varnish or cover it in resin.
See my GitHub and printables.com for some 3d stuff that you may like.
Frankly this job would be better 2D printed on acrylic/ohp transparent sheet and mounted over your reactive layer.
3D printers do a very bad job of 2D printing despite the claims of Hueforge, lithophane and 'Wall Art' protagonists. The pixel equivalent for a standard nozzle is one extrusion width, usually 0.45mm so about 55dpi resolution; General 2D printers generally operate between 300dpi and 1400dpi, 'Photo' printers offer more.
You might approximate your desired effect by printing with glow-in-the-dark filament. For shading print one or two layers over a black substrate and for maximum brightness print three or more layers over white.
Cheerio,
RISPONDI: Simulating black-and-white gradients in 3D printing using structural patterns: tips on technique and dimensions.
Thank you so much for your replies.
This figure would be placed in a frame with a 7 cm high frame and a UV LED strip along the edge that illuminates the figure. For this reason, I wanted it to be beautiful, even physically. _KaszpiR_ The female figure is 20x25 cm. I'd like to avoid placing the white behind it because, in that case, to ensure it's illuminated and not obscured by the black print, I'd have to leave space between the layers so the light reaches the white.
Diem the idea of more layers and more brightness isn't bad, I'll think about it and above all I'll talk about it with the print shop.
I'll probably do a couple of different tests to see the effect, including trying out a resin mold. Do you have any advice on how to create the file for printing if I start from an AI (Adobe Illustrator) file?
Thank you very much to anyone who responds.
a UV LED strip along the edge
That won't give even illumination. You need to spotlight from far enough away to allow the light to spread.
@_kaszpir_ is suggesting you light from behind - much simpler. If you are intending to use LEDs in any case the best result will probably come from using an LED panel and mounting a printed transparent sheet in front; no need for 3D printing at all except, possibly, for the frame and mounts. Salvage a backlight panel from an old laptop screen and experiment,
how to create the file for printing if I start from an AI (Adobe Illustrator) file?
I don't know Adobe but it's bound to be capable - create a layer for each shade just as you would for spot colour printing and import them into your 3D CAD scaling them to the layer thickness you intend to print.
Cheerio,