Author Topic: vector vs raster  (Read 107 times)

mattm58

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vector vs raster
« on: September 14, 2018, 01:23:29 PM »
I do a lot of small wood engravings (<75mm square).  I'm using T2 to run the A3.  To date all the engraving has been done by using jpgs, and horizontal/diagonal engraving.  Times vary from 4-12 minutes typically.  My question, will converting these to vector reduce the time?  My assumption is yes, but I'm not familiar with creating vectors.  I've watched Nottingham's youtube video for converting in inkscape, but that appears to just outline.  How do I hatch the areas to fill?

I tried using T2's sketch hatch feature, but it appears it just outlines, then does the same type of top to bottom engraving that the raster does (similar to  a printer).  Since it did the outline first, it actually took longer than the raster.

Does anybody have links to how one would convert the jpg (with filled areas) to a vector to speed burn time?  I've got the raster burning working fine, just looking for potential ways to speed things up.

Attached is a sample of the type of image I'm using.

A3 2.5w with longer rails making it ~85cm x 40cm

ggallant571

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Re: vector vs raster
« Reply #1 on: September 14, 2018, 04:24:39 PM »
Looking at your image I would guess that converting to vectors would be a waste of time and sacrifice quality. My general rules for etching are minimum line width is 2 pixels and spacing is 4 pixels. There are a number of places in the fish that do not meet these guide lines. It is all a mater of taste when dots are missing for bleed together.
 
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Zax

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Re: vector vs raster
« Reply #2 on: September 14, 2018, 05:15:31 PM »
I would always do line art like this as vector, you get better quality and it's much faster.

This example takes 20 minutes using 0.15 resolution ant 1000 feed rate, the same image and settings using vector (I used auto-trace in T2Laser) is only 2 minutes, and with hatch enabled so you still get the fill it's 5 minutes.

You don't need Inkscape or anything else, just use auto-trace. It's one click and your done.

It sounds like you were using Sketch Plus (Overlay) which does raster and vector, you don't want that so just leave all the Sketch modes off and it will convert to vector. If you want hatch just check that option before tracing.

mattm58

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Re: vector vs raster
« Reply #3 on: September 14, 2018, 06:02:07 PM »
Ok Zax, what am I doing wrong...

I open T2, open the image, set feed rate at 1000, velocity at 4000, set hatch options/Custom spacing at .15, Mode = black & white, horizontal, select Sketch (Hatch), run auto trace, generate g-code, (7428 lines), hit control laser and it says it's 21 min, 9 sec.

I leave all settings the same, uncheck sketch (hatch) so it does as raster, generate g-code (12213 lines), hit control laser, and I get 19m, 21sec.

A3 2.5w with longer rails making it ~85cm x 40cm

ggallant571

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Re: vector vs raster
« Reply #4 on: September 14, 2018, 07:47:39 PM »
I raster burned the image on scrap high quality plywood in just under 9 minutes with:
    Laser                  2.5W
    Traverse rate      1800 mm/min
    Burn feed rate    1200mm/min
    Resolution          0.1mm

Result was quite nice. Perhaps a little darker than necessary. The feed rates could be higher.

BTW - what type of fish is it?
SARCASM - Just one more service we offer here.

Zax

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Re: vector vs raster
« Reply #5 on: September 15, 2018, 11:37:25 AM »
I set resolution to 0.1 (only used for sizing) and loaded the image.

It's 74 x 74 mm.

Using 1000 feed rate with no hatch I auto-traced and it is 1 min 22 sec to engrave.

The same settings with hatch at 0.15 is 6 min 25 sec.

It's just under 10 minutes without using DXF optimizer.

Try it again, change the settings and load the image. Then with hatch off try auto-trace and see if you get ~1 minute.




mattm58

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Re: vector vs raster
« Reply #6 on: September 17, 2018, 10:59:21 PM »
Ok Zax, finally got a chance to try things, here's what I did:

Hatch Custom Spacing set to .15,  (feed rate, linked, at 1000/rapid at 4000

Load image, generate as raster, time estimate is 12m, 56s
Load image, autotrace (outline only), time estimate is 1m, 25s
Load image, set sketch/hash, autotrace, time estimate is 9m, 56s
DXF Optimizer on, Load image, set sketch/hash, autotrace, time estimate is 5m, 42s

Not quite the same as what you got, but the dxf optimizer is the key

gcode attached

A3 2.5w with longer rails making it ~85cm x 40cm

Zax

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Re: vector vs raster
« Reply #7 on: September 18, 2018, 05:02:03 AM »
Sounds about right, I probably had rapid set to 2000.