Using vector for engraving instead of raster

qa

#1

Ive noticed in several threads the mentioning of using vector for cutting and raster for engraving. Most of the artwork I use for my current engravings is vector and so are my cut lines. Is it necessary with the GF to convert all engravings to raster? In some very detailed illustrations, wouldnt users lose some of the detail when converting?

Jake


Converting unfilled, unclosed paths from Cut to Engrave fills them
#2

Not to worry, the GF plugins and web app will accept vectors for cut lines, as demonstrated in many of the demo videos.


#3

Thats not my question. I completely understand that you use vector for cutting, my question is about using vector for engraving. And is it necessary to convert to raster to engrave or can you leave the design as vector and set that to engrave. So essentially identifying what parts within a vector file is cutting and what is engraving, but leaving all of the assets vector.


#4

There are some term overlaps which I believe are causing issue. I am fairly novice myself, so am likely also using terms wrong. But I believe I see what you are asking.

Vector graphic files can scale up/down without pixelating, because they are calculated/rendered. But the vectors themselves are just the lines and arcs.

In a visual image, you often have things colored in. This is “fill”

When the laser processes your image, all of the lines (the actual vectors) are vector cut, because they are simple lines, with no width, so the laser does the thinnest action it can (single pass at the speed/power you asked for, which will result in cut or engrave, based on the power/speed).

All of the FILL (color in an area enclosed by vector lines), is filled in with the process of rastering. Which just means “Move from one side to the other, then move down slightly and repeat.” And that is the only way that a laser CAN fill an area in.

So nothing changes in how you make your file on the computer. Vector graphics with strokes and fills. The raster/vector fill/engrave/cut is a distinction at the laser end so that it can re-create what your graphic file was.


#5

Just use different coloured lines(and or fills) to pick how deep you want it engraved even if it is vector.

You can engrave a line or cut it depending on power. So you can use full vector graphics for an engrave image or cut the whole way through. If your vector path is filled with a colour it with engrave with that depth


#6

Thanks @jacobturner for the explanation. If Im following, any “filled” object whether it is raster or vector is engraved and any object that is still a “line” (meaning using the pen tool to draw from point to point, without converting that item to a “filled” item) will be cut. Even though a “line” and a “filled” object can occupy the same amount of space.


#7

That looks like it might be correct, although the GF motion plan code may perform some optimizations to say “this fill is smaller than I can make, let’s draw a line instead”.


#8

Not quite. A line is a line, just with different stroke sizes. So in your image, there are two black lines, the one on the left also has a blue line inside/on top of the black line. If you had those thin blue lines around the perimeter of the right side, then I would say the black was a fill of the thin blue box (and since you had two colors, you could command the laser to engrave the black, and then cut the blue)

These lines segment the image into three zones, which are each filled with white.

Most of the cutting we have observed has been hand-drawn images, so we see it appearing to raster engrave for drawn “lines” but this is due to the image being a photograph, so EVERYTHING is a fill, since no vector data exists.

Vector data is saying something like "Move 25mm along the X direction, then 5mm along the clockwise arc of 7mm radius circle with the center directly below this point in the X direction, then move 10mm in the Y direction, then move in a straight line back to the start point.

If these commands were sent to the laser cutter, that is precisely what it would do, at the speed and power it was assigned. If the image also had the area inside of that odd shape colored, and that color had been assigned a speed and power, then the next command (or preceeding) would be to move back and forth along that area, at the speed/power assigned for the color.


#9

I had the opportunity to watch a GF engrave/cut a hand drawn sketch.
Watching the screen you can clearly see that the software has “vectorized” the scan (i.e. it reduces the complexity).
Then when you power it up, the GF does a line / step over sweep on everything inside and a single continuous cut around the perimeter. This is for the simplest case of a black/white scan, and I bet it is a preprogrammed workflow.

For more complex stuff you can pretty much see what @jacobturner is saying about choosing in the demo Dan did here: https://www.youtube.com/watch?v=WJqUQ-Uw080 (go to 6:11)


#10

I think @jrmize was showing what it looks like in a program like Illustrator – if a line is still a “line”, when it is selected it shows the selection down the middle, as that is the path. When you have “outlined strokes” in illustrator, it shows the paths as the bounding areas (because those are the paths). So the blue lines are just selections, not actual art.


#11

Ok, I understand your question now. Btw, I’ve been using an 80w Rabbit laser system for about 6 months at my local maker space, primarily engraving custom cutting boards and pub glasses, so have had a fair amount of practice with the “normal” workflow with this sort of setup (i.e. truly crappy software).

I have used both bitmap/rasters and vectors for engraving in the past, and have since given up on using vector files for engraving. Unfortunately, I don’t have a photo of the end result, but consider this file (browser-friendly bitmap shown, but trust me, this was a true vector file):

What I was hoping was that all the black areas would be “engraved” – burned down to a specific depth as defined by the power and speeds settings for “black” in the Rabbit software. What I ended up with was a meticulously-detailed outline of each black area. Still looked great, but wasn’t what I was looking for.

My current strategy is to use hi-res 2-color bitmaps, matching the resolution in DPI (dots per inch) to that of the laser. In my case, the Rabbit says it’s good for 800 dpi, but 500-600 is much more realistic. Here’s an example of a woodcut that I engraved at 300 dpi:

Btw, this image illustrates one of my biggest reasons for purchasing a GF. Notice that the image is aligned along the left side of the bamboo instead of centered. Despite my best efforts to calculate the center (and using the Rabbit’s boundary preview red laser) the actual cut was offset. I am eagerly awaiting my GF, so that I can have a live preview for alignment!

Hope this helps…


#12

I have any number of screwups like your cutting board. It’s the reason we have that feature. You’re not alone. :wink:

So there’s a few things you can do.

For bitmaps, you can engrave them.
For vectors, you can engrave them, as you might for text. You can cut them, as you might for a shape. You can hairline-engrave them, which is like cutting but at lower power, so you trace the outside.

If you look at the macbook skin on the glowforge homepage, you’ll see the logo over the center was cut, and the lines were hairline-engraved, and the text is a vector that was fill-engraved.


As a Designer, I want to start prepping, so