Re: Trello (Public Roadmap)

@JKC20 Great start. Now get all the descriptions filled in. :slight_smile:
Make all the Leads in those projects responsible for filling in the status info.
You should have everyone preface their feature requests to support@snapmaker.com with
a “Feature Request:” to help your support people out. Maybe even:
Feature Request Luban:
Feature Request Firmware:
Feature Request Touch Screen:
Feature Request Hardware:

… just an idea. :grin:

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I’m sad to not see the hand control on the road map. That one of the first things I would buy.

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Good to hear your feedback.

image

IMO, our moveable touchscreen, is a ok alternative to handwheel control(Jog Panel tab). If our touchscreen is fixed position, then the Handwheel seems more compelling for me. Let me know your thoughts.

Bests,
David

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@whimsycwd, What the Touch Screen and/or Jog panel lacks is a way to set a speed and push and hold to have it move continuously and smoothly. What also would help is if the rotary function could be simulated by rotating your finger around a circular track.
I started off my career by being a machinist. I have a certain feel and dexterity with an actual rotary hand wheel that you can’t get from a virtual control. A circular touch track would go a long way to being able to use that dexterity.

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In this I’m totally with @Tone . At work I’m programming industrial robots and the most important thing for me are physical controls to move the robot. Most manufacturers are moving to touch screen control panels, but are keeping their hard keys because of the physical button feedback and the possibility to find those buttons blindly to control the robot while watching it, without having to look at the screen to find your soft key.

Edit:
Furthermore I think it would be nice to have the possibility of some manual controlled machining. For easy things like the laser jigs of @jepho it would be easier to use a jog wheel than to create some digital model for processing the material.

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There are some interesting and stimulating viewpoints to consider in this thread, @Tone, @whimsycwd and @Melanchrom.

I had considered the use of some form of manual control when looking briefly at jig use with the laser etching tool. It is not very convenient to run test pieces for laser power at this time. A manual wheel to adjust power settings could utilise a single test piece… with power settings settings adjusted after jogging the laser module head to a new location. Something like the fine tune option but with the power of the laser controlled by the user.

A click wheel with detents at 5% may be the way forward. With rotary controls, I think the refinement I would like to request is to have a variable feel for the pressure required to move the control but this would probably be adding to the cost of the part.

As a beginner I have no clue what I really need (or want) when it comes to making the best use of the machine provided. I can see some of my immediate needs and then only in the rather simplistic terms of a new user because of my lack of knowledge and understanding.

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Hi, @jepho It’s true that a manual control over laser power can be handy for tuning the right power.

I would like to propose another software alternative. If we design a tool in software. It can let you choose a few pattern(ex. 11 parallel line, or used design pattern). Input the power low & high bound, (ex, 50, 80), then it generate a gcode for you that every line with different power(50%, 53%, 56% … 80%).

Does it serve your purpose better? Let me know your thought.

Bests,
David

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@Tone @Melanchrom Thanks for your feedback. It does help us to prioritize tasks. It will be added into the roadmap. Regarding to CNC feature, Snapmaker still has a long way to go. Your experience and feedbacks are crucial to the future roadmap.

Bests,
David

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Hi David;
Thank you for your response. I suspect that it will be choosing the power boundaries to select that will be the issue for many people. At the moment the laser settings are pretty much seat of the pants guesswork. This does not really fit with using a machine that can work positionally to an accuracy of 0.1m. e.g. when we use the jog control, the stepper motors have no difficulty moving the module in 10ths of a millimetre. The laser power setting is not so fine grained and once it is set, that is what you have to stay with.

A small diversion: I think of the laser power in terms of an ink dot being placed somewhere on the page. In the days when newspapers were our main source of news, the papers had little access to technologies that produced colour and the images were all monochrome because only black ink existed for long runs of hundreds of thousands of copies. Colour printing was available but it was far too expensive for printing a newspaper that would be thrown away after it was read.

Printers who printed newsprint or commercial printers who printed by single colour letterpress machinery used a method to get variations in tone despite only having black ink for their printing output. The solution was to print using a halftone method that still placed black ink on the page but could vary its density by means of a halftone screen. Sufficient to say that the process produced an effect that typically suggested that an image comprised black, white and many different grey coloured inks. The image below is instructive.

In this halftone image every black dot has been laid down in a regular grid. The illusion of tonal changes through a range of grey tones is maintained by the dots being printed smaller. The less dense areas are lighter grey than the denser areas. The nose projects a shadow that is pure black. The image resolution is highly magnified to illustrate the halftone effect and the image should be viewed at a distance so that individual dots of ink are not visible. That way you will see the illusion of the grey tones rather than just black ink dots.

One other image that may assist you to understand where I am trying to go with this discussion is a zone system chart; which I have attached to this post just below this sentence. The Zone system was used by early photographers and is based upon Ansel Adams work to describe locating the exposure of film in the correct place.

Each of the labelled tones demonstrates a different tonal value. Black (0) could be assigned 100% power and White (x) could be assigned the off position. Each tone in between could represent a 10% change in value. This type of system would permit variable laser power to be applied to images and improve upon the results that are currently obtainable with a single power setting and dwell time changes. It does not obviate the need for an infinitely variable power adjustment nor one that could be made while the machine was actually running.

An integral part of the laser power is its positioning. I have already acknowledged the machine resolution being capable of as small as a 0.1mm movement. Where I feel an improvement could be made is in the area of positional value readout. Cartesian coordinates are how the machine finds its next location and the software should be able to display where the module is in the ‘X’, ‘Y’ and ‘Z’ positions. The position of best focus must be known to the engineers and it would be helpful if the ‘home’ position for perfect laser focus could be added to the thickness of the workpiece (a new input value) so that the laser would be in perfect focus without the user trying to determine the best dot size for the laser beam.

Other input values that are suggested are start position which I would prefer to be variable rather 0,0, as determined by the machine. If Luban could let us determine our own arithmetically derived start position, there would be no need to jog the laser to the point that approximates where the user wants the laser to switch on. The values which affect laser image include dwell time, speed of movement, impurity density and image algorithm should be available in all modes of operation. For a black and white image, the engineers did not include dwell time settings.

I could make a case for manual adjustment of power and travelling time. The positional stuff should all come through the Luban software because these are known values. The rails and modules do not change their locations from what the assembled machine permits. I would want any solutions to help me to avoid the need to run 40 different tests of laser power and create duplicate workpieces to do so. A manually adjustable power setting and work/feed time would let me use one piece of scrap wood and run numerous tests without having to stop and use my computer and Luban to assemble another series of test conditions.

There you are David, I hope I have made this relatively clear. :thinking: :+1:

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I am kind of lost. LOL, Let’s discuss further to clarify.

  1. We did have a greyscale mode, do exactly halftone trying to do.
  2. The material varies, it profoundly affect results. I think a little bit trial and tweak is unavoidable.
  3. Because of the stock can be vary. So that set origin by user(workpiece coordinate) is very useful. For standard stock, we can use Camera to help us to have a machine coordinate instead of workpiece coordinate.
  4. The power of laser beam is not linear, and the combination with material(Wood, MDF, …) make it even worse. It is hard to have a one for all solution. And a jog panel to control laser power is responsive and easy, but to verify the best power need the machine to work on target material for a trial move.

Hi David; thank you for your response. I am sorry if I lost you. I will try to deal with one single issue at a time and that should help the clarity of this debate. You have pointed me to a linked presentation of a cat being etched by laser. I am going to paraphrase your words so that you know how I have understood what you have written. If I am mistaken then I apologise and we should start again.

You say this is the laser operating in its grayscale mode and it is doing exactly what the halftone printing process is trying to do. If that was the case, I would expect the greyscale images to be produced with a type of accuracy that I do not find in the greyscale mode. Having tested the laser capabilities quite extensively, I decided that perhaps I must be doing something wrong.

I have just used the same settings as are used in the video presentation. The image file I wish to print is currently printing and I will talk about it once it comes off the printer. For absolute certainty, if you were to send me the cat file, tell me the settings which were used and the size to use and if all things are equal, I should be able to produce a file that is similarly detailed.

For now, I will confine myself to discussing what half tone represents. The variation in ink dot can be the size of the dot on the page (analogous to today’s pulse width modulation) or the spacing between the dots (frequency modulation) and it may also be represented by a combination of both techniques. That is to say dot size and space between the dots combined. My example image only demonstrates a change in ink dot size but the spacing between every dot is absolutely regular.

For your half toned laser image I would expect there to be information in the image file that turns the laser on and off at varied intervals (frequency modulation). I would also expect a reproducible pattern to represent every tone available. When selecting which greyscale algorithm I want to use, I assess each one with the image at the same size and then I can see banding artifacts and the smoothness of the digitising process.

The original halftone process required the operator to insert a coarse material screen of between say… 85 and 150 lines per inch (lpi) between the image to be screened and the camera used to image the picture. It would break the path of the light coming through the screen to expose the film by diffraction and halftone printing was the result. The end result is an optical illusion that requires the image to be viewed from a distance where all of the dots coalesce so they are seen by an observer at the correct distance as a continuous tone image.

To aid the clarity I have a couple of images for you to view.

The first image is a screenshot of the file I am currently still printing. I tried to process it in each of the algorithms available for greyscale. The image file is a greyscale image processed at a density of 10 and sized to 95mm square. The algorithm which appeared to give the most pleasing appearance in Luban was Sierra2. (I think that we could usefully have a snapshot facility to compare the algorithms when we are processing images for greyscale)

This first image is how I saw it in Luban… please enlarge the image and tell me what you think the severe banding is between minus 10 to minus thirty. It is actually visible everywhere on the page but between those numbers it is quite severe disruption of the image. It indicates that what is being seen is not the laser software copying halftoning because the man’s head did not and does not have these light bands traversing it. It strongly suggests that the greyscale algorithm is dithering the pixels in an effort to represent tones that are currently out of reach of the software.

Another image may help to clarify this matter for you with more certainty. It is an enlarged section from the first image. It is taken from the centre section of the man’s left eye.

This is a reflection of the combined pulse width and frequency modulation. Tonally speaking, there is very little tonal difference yet I think I see 5 different pulse widths and 2 different frequencies. The regularity is responsible for the banding seen in the previous image and the patterning suggests very strongly that this is a dithering algorithm rather than a halftoning pattern.

The available choice of greyscale image processing algorithms can be summed up like this:
Floyd-Steinberg - dithering algorithm which works by error diffusion.
Jarvis-Judice-Ninke - dithering algorithm works by error diffusion (uses two rows)
Stucki - dithering algorithm works by error diffusion - faster than JJN
Atkinson - dithering algorithm partial error diffusion may wash out contiguous areas
Burke - dithering algorithm works by error diffusion (faster than Stucki and single row)
Sierra 2 - dithering algorithm works by two row error diffusion.

This implies that the enlarged image told me the correct story… that is to say that halftoning was not being applied by the Luban software algorithms for greyscale images. So that leaves me asking for halftoning to be included on the future roadmap and implemented whenever it is possible. It will provide the user with images that appear to be continuous tone rather than dithered.

You may remember that I was exploring potential methods of halftoning images taken into Luban software. I don’t think that my discovery that greyscale images are being dithered (rather than halftoned in Luban) diminishes the value of Snapmaker; but factually speaking image processing is not as convenient as it could be. I was requesting a roadmap insertion that considered the possibility of using the Luban software to drive the laser so as to provide an effect that worked in a manner similar to halftone screening.

David, I sincerely hope that clarifies my position on the point I made about halftones.

The image is still printing and looks to have another 40 minutes to go. I will post it later if I am still awake. :sleeping: :sleeping_bed:

I have just retrieved my print… not fantastic but this was the output…

The second enlarged section image confirms that the software is doing nothing more than dithering the image…

I have done some research. Yes, you are right, they are different, but normally, I will prefer ditering over halftone, It produce finer detail, IMO.

  1. https://photo.stackexchange.com/questions/5779/what-is-the-difference-between-halftoning-and-dithering#:~:text=When%20colour%20halftoning%2C%20the%20grid,more%20tones%20than%20are%20available.
  2. https://www.cs.princeton.edu/courses/archive/fall00/cs426/lectures/dither/dither.pdf

image
It looks ok, but not good. You can have much better result after some tweaks.

  1. Make sure the laser focus properly.
  2. Rotate the stock, sometimes the texture of the wood has significant impact.
  3. Choose Movement Mode(from Line mode to Dot mode). It will need more time, but the result will be more clean.
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Thank you David; for the information contained in the response. As noted previously, I had set all of the settings which you have detailed. I will try to bring the dot density down because it looks to me as if there is far too much activity at each pixel of the image. The worm shapes which are visible in my enlarged section of the print are absolutely typical of error diffusion algorithms. My link below is to an extremely well written and erudite paper concerning how the quality of halftoned images can be assessed, measured and evaluated.

My position on dithering (which is one particular form of half toning) where a single colour is made to represent gradations in tone, is that it does not usually produce an illusion of one single continuous tone in quite the same manner that halftone screens appears to do.

I have attached my own image to which I have created and applied a halftone screen. The cell size is circular and I have tilted the screen angle to a standard 45 degrees. When you look at the image you can clearly see every one of the dots of different sizes. The halftone screen which I created was a regular grid so that only the amplitude of each black dot is modulated. The frequency was left untouched.

When you view the image at the correct viewing distance, you will note that all of the dots coalesce and the picture appears to be a single and smooth continuous tone from black to white. The software I have used to demonstrate this principle is not used for pre-press graphic design and printing so it cannot achieve the sort of dot sizes which one would associated with high quality halftone printing, nevertheless, I am hopeful that it is an instructive demonstration.

Link to paper explaining dithering and halftone application:
https://www.diva-portal.org/smash/get/diva2:17782/FULLTEXT01.pdf

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Hello David; further to the foregoing discussion, I have looked at the very helpful definitive guide. It is clear that different materials will react differently to the laser beam. The settings provided are a useful starting point. I tried to download and etch the example files and I cannot change the position in Luban, nor can I resize the file if I use it to open the g-code file. Is there a way that I can do this? It would be a great facility for people to share the g-code file and then resize it to suit their materials. I had wanted to put the cat onto a 100mm square (with a 5mm border from the edge) and cannot work out how to do that. Any assistance you can provide would be very much appreciated. By etching your own file that is known to work well, I could understand better what each of the settings affect once they are adjusted.

I attach a Luban screen shot that shows the Luban workspace. Luban’s workspace window does not appear to know that the cat file is loaded because none of the visible settings are active and all set to zero. The cat picture sits on the top right of the coordinate space. When clicking on the bar that says “load g-code into workspace”, the file is confirmed as having been loaded successfully by the status bar at the bottom of the Luban window. Clicking on the laser g code generator segment does not show the cat file and so adjustments cannot be made to it.