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Re: crashing....
« Reply #10 on: July 23, 2012, 11:23:32 AM »
Hi Tweakie,
my apologies for being slow on the uptake, but I'm not 100% following the "one bit dithered half-tone" method you decribe. I'm semi-familiar w, say, converting an image to 8-bit while saving it in photoshop which then allows for dithering, but I don't quite get how I'd translate that method for a grayscale image? If I'm following part-way, then your reference to one-bit would be having the image formatted as grayscale/solely black v white, but after that all those "oops, slipped" moments getting dropped on my head as a kid start catching up. The way I've been approaching the problem of producing a quasi-realistic photo rendering via pencil has been to try and getting the highest res engraving image, then producing different files of the same image (kinda like color separations or screens for a silkscreen, etc), w each file isolating areas lighter or darker, then making successive passes w one file after another. In each pass I'll change the pencil density (2H,HB, that sorta thing): btwn the grain of paper, successive passes, and differing tones isolated btwn files, I can sorta get somewhere but I know there's gotta be a better way. ANY advice you feel up for sharing would be incredible, honestly: I just started in on this and am frankly barely treading water trying to get a solid grasp on the what/how/when/ etc pf all this....

Offline Tweakie.CNC

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Re: crashing....
« Reply #11 on: July 23, 2012, 12:19:37 PM »
Hi Banks,

It’s my fault entirely because I misunderstood your earlier post.
What I have been describing is creating the optical illusion of shades of grey (halftone) by a 1bit method (dithering).

If you need to draw, with a pencil, and create different weights of line (shade) then a better approach to this may be to try Roger’s Plot screen http://www.machsupport.com/forum/index.php/topic,5182.0.html
With differing Z depths for each pen (selected by color in the original drawing) the same HB pencil (suitably mounted) should be capable of producing different weight’s of line.

Just a thought.

Tweakie.
KEEP SAFE !
Re: crashing....
« Reply #12 on: July 23, 2012, 03:35:22 PM »
Hi,
yeah, sorry if I was hazy about wwhat exactly I was trying for. Thanks for the link: seems pretty close to the approach I've been taking, just streamlined, efficient, and all the other things I never seem to manage on my own. Sadly, I'm completely Corel illiterate so need to pull a solution together that's specific to photoshop, though - again - it was heartening to read the post you linked as it seems, at the core of what's going on, to be how I'm trying to handle it, i.e; treating different tonal "areas" sorta similar to separation's in like manner to a print, as well as tweaking the tool parameter's for each pencil tone assigned to those separations, etc.. Sorry, I'm kinda babbling. I'm trying to play around w 8 bit/ dithered image files, as well, just to rty and get some sorta mark making thats not solely line after line going, but haven't really found an easy g-code interpreter (thanks for the previous links, but both of em seemed to much for my dumb brain to handle) but hopefully I'll find something and can really try out that part of your suggestion. Again, sorry for the babbling: I'm absolutely grateful for you taking the time to help me out w this, so thank you

Offline Tweakie.CNC

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Re: crashing....
« Reply #13 on: July 24, 2012, 01:44:24 AM »
Hi Banks,

I am most interested in what you are trying to achieve so please post some pictures or information as you progress, it really sounds like a fascinating project you have undertaken.

Tweakie.
KEEP SAFE !
Re: crashing....
« Reply #14 on: July 24, 2012, 02:32:14 PM »
Hi Tweakie,
Thanks for the interest, in addition to the help. I'll absolutely post a few images for you shortly - I actually need to run out and get some different paper samples today, since it's seeming pretty necessary to both have something that's A.) heavy enough that the initial weight/"tool depth" of a pencil set for producing dark areas will chew up anything lighter. plus needing something w a random enough grain that'll help producing a more "random"/less mechanical quality to the graphite, etc.
And now i'm babbling again.
I'll hopefully have somehting more coherent than my writing to post you shortly...
Re: crashing....
« Reply #15 on: July 24, 2012, 06:09:29 PM »
Hi Tweakie,
I know this is pretty far off from the original topic of this thread, but it seems (just through a quick scan of the forum) that you've got a tremendous amount of personal experience using the mach software, so I thought it's at least worth a try asking for your advice, independent of this thread's topic. Basically, I've got alittle stepper, 3 axis arrangement set up at the moment (I ending up building it mainly cus I was so frustrated waiting to assemble all the parts for the next machine), but I've been pulling together components for a much more permanent solution. The new machine's gonna be servo/linear motor based, and the drives are Kollmorgen S300 and S600 servostar's (I'd stick only w the s300's but the X axis positioner requires more amps than the 303 and 343 drives so I've gotta use a 620 for that). Originally, I was planning on using Heidenhain exposed linear encoder's, and switching their analog/11 (micro)app signals to TTL through 602E interpolation units, but I'm switching them all to RLS magnetic encoders (LM10). The final part of this whole arrangement left to be decided on is the motion controller. I'm planning to using a Galil DMC unit of some sort but I'm not 100% on which one would be best (this machine's gonna be a larger version of the plotter sorta arrangement I've been describing, with the exception that this new one will have a much larger work envelope as well as higher resolution, etc - I know this might all sound over-elaborate, but my job/profession is as an artist. I primarily work as a sculptor but I also make drawings, except I've ruined my back and need some way to still be abe to produce drawings while I'm physically unable to do so anymore on my own). Really, any advice you could help me w here would be fantastic - I'm leery of either getting something either unsupported or that require's so much fiddling w to get working that it's just too much of a headache to be really worthwhile. Sorry again I'm posting this all in an unrelated thread, but I figured I'd better take advantage of this chance to ask you while it was available. Thanks in advance

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Re: crashing....
« Reply #16 on: July 25, 2012, 01:17:00 AM »
Hi Banks,

Once you move into the area of servo drives, encoders etc that is more in the domain of Mr Hood's knowledge base than it is mine. If you post any questions you may have in a separate thread I am sure he will know the answers and of course, be only too willing to share his knowledge.

Tweakie.
KEEP SAFE !

Offline BR549

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Re: crashing....
« Reply #17 on: July 27, 2012, 01:08:15 PM »
HOW large of a pen plotter are you trying to build. Old Pen plotters (rarely used anymore) are extremely cheap these days. I still prefer the PEN drawn look for drawings as they tend to be a work of art not just a replication.

Just a thought(;-)TP