If you have a height map that is 16 bits will using more than 256 layers (say 1024) produce better results? Basically is the extra resolution in the height map usable?
Hi Gary,
That’s a good question!
I think your theory is correct. Since a 16 bit image contains more tonal values, I would assume that a 16 bit image can benefit more from a higher number of layers than an 8 bit image can.
Have you tried the 3D Sliced function yet?
We’d be happy to see your results and the settings used.
@LightBurn might have some more insights.
Welcome to the site…
Grayscale files are generally not set up for 16bits (two bytes), since 3dscan uses a maximum of an 8bit value (byte). These only contain a single byte for each dot determining the spots grayscale intensity.
Doubt you can get much better resolution irrelevant of the number of bits over 8. This is 256 different levels of gray, which most lasers and materials can’t really do. At 16bits you’re talking a much wider gray range, that isn’t likely to be able to be duplicated with a laser and the selected material.
Fiber lasers have only an 8 bit power level setting on the fiber source.
This is an explanation of how 3dslice works on a fiber machine by Oz in the fiber beta area. You might not have access to it, but I"ve copied the relavent answer here.
With 3D Slice, each pass is thresholded to the current threshold value, and the result is run as a 1-bit image. If you use 256 passes you get exactly one pass per gray-level in the image. Every pixel at or below brightness 255 for the first pass, every pixel at or below 254, then 253, and so on.
If you choose 128 passes, you get every pixel at or below 254 for the first pass, then 252, then …
It “clusters” the layers together into batches if you use fewer than 256 passes, and will duplicate some layers (with even spacing) if you use more than 256. 384 passes would duplicate every 2nd layer. 512 passes would duplicate every layer.
This should cover your question. Do you have a laser of any kind?
in 3d slice mode, the power resolution is irrelevant; you aren’t setting power based on grey value, but using the grey value to derive the mask for that layer via thresholding. I’ve implemented 16-bit (and 32 bit, lol) tiff support in my own implementation of 3d-slice, as it was bothering me! The results show some difference, and it certainly allows for wider range of pre-processing adjustments.
I will have grayscale files with 16 bits of resolution (10 bits of true information encoded into 16 bits because that’s just how it works). I understand this is not generally the case. The idea being that if I chose 1024 layers it would do 1024 1-bit passes instead of 256 1-bit passes. Clearly there isn’t a use asking for 65535 layers but increasing from 256 to 1024 may be helpful.
Some of my jobs run for two hours, would this not double that?
I’d like to see the results.
Would increase in linear fashion I expect so 4x the time for 1024 lasers compared to 256.
Does LightBurn, specifically for images with the 3D sliced option for galvos, use 16-bit greyscale images yet? Apparently it used to convert incoming images to 8-bit greyscale, but I recall reading that moving to 16-bit was on the list.
When I’m engraving to-scale terrain carvings on my CNC router, I certainly use 16-bit source images, as 256 steps is not at all adequate. I haven’t delved into 3D sliced galvo work yet (just haven’t gotten around to it), but 16-bit would be very desirable. (For one, you can divide 65536 much more evenly vs. 256 when you’re not doing 2^n steps.)
Ah, found the reference. Is the 16-bit code in 2.0, perhaps?
It’s not supported yet. I had to write a new resampler that supports arbitrary orientation while keeping correct image registration.
I’ll be adding 16 bit support to that before long. That part is actually relatively easy - the harder part is making sure that everything else that works with images in LightBurn will handle a 16 bit source. Adding support for 16 bit image sources for slice mode inherently means adding support for them to everything else, a user might inadvertently load one without realizing it and just use it as a normal image.
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