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Trey Tull
03-19-2018, 10:06 AM
I was working on some large panels over the weekend that had an image of a tree and the roots extending out on each side.
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I split the image in half and engraved each half onto a separate piece of wood. I filled the tree in with black, like I normally would but while engraving the trunk, it would go all the way out and stop at the tip of the root. For each pass, it would travel between the red lines on the image above. This made the job last over an hour for each panel. It seems like it would only travel over the area that needed to be engraved at that time and not worry about the roots until it got that far down. I check for a line or a spot out in the image and didn't see anything that would cause it to travel over all of that white area.

There were also a few vector lines and a vector line to cut the piece out. Would that effect the raster?

Am I missing something in corel or something in the ULS settings?

Mike Null
03-19-2018, 10:32 AM
Trey
I would have a look at the artwork in wireframe view to see if something in the drawing might be causing the issue. On the Trotec job control, we have a setting that will force the engraver to make a full pass throughout the drawing as you are describing.

Kev Williams
03-19-2018, 12:24 PM
What that's called is 'white space' engraving, it's when laser sweeps the entire 'imaginary', aka 'bounding' box that surrounds a particular graphic, whether anything is there to engrave or not. With images, not sweeping the whole box may be dependent on how white the background actually is, and possibly the type of photo; jpg's may full sweep where bmp's may not... just conjecture, but testing may bear this out...

You mention there's some included cut out vectors, if they were in the active engraving layer, then it's possible the raster took them into account--

Brian Lamb
03-19-2018, 1:16 PM
What Kev says in his last line has been my experience with the ULS laser... if you have a vector path as well as raster, I have had quite a few issues with the laser doing a raster pass on the vector item, even though it shouldn't. Try deleting the vector out of the graphic and see if your raster works as it should.

Trey Tull
03-19-2018, 2:48 PM
Thanks for the tips guys. I was wondering if the vector had anything to do with it but I didn't have time to experiment with the production piece. I will try it again with a smaller version.

Glen Monaghan
03-20-2018, 10:32 AM
It is using a "bounding box" approach, sweeping the head the full width of the widest part of the rastered area. That is much easier to set up than the more time-efficient approach of examining, on the fly, each raster line pixel-by-pixel to determine the minimum required sweep. If nothing else, you can work around this behavior by further splitting your graphic vertically, just above the spot where the roots spread out, so that your bounding box for the top part covers just the tree trunk. Depending on the size of the graphic, you might decrease engraving time by another significant amount if you also split the graphic again near the bottom where the widest upper roots end and you only need to sweep over the narrower lower roots.