lcd contact printing mask

I recently posted in my blog about a idea im working on right now. Its to use a lcd screen as a build mask for uv or near uv curing resin.
my blog is
[technomancermaker.blogspot.com]

without repeating it all here part of the idea is also taking the slice images and turning them into a mpg video file with the audio track imbeding z-axis timing pulses for varying thicknesses. something like 1000hz tone with a 1 pulse per frame @ 1micron slice thickness, 500hz tone with 1 pulse per 50 frames for 50 micron thickness and 100hz tone every 100 frames for 100 micron thickness. this is of course under the premise that the frames are sliced at 1 micron increments. if you were to slice at another increment you can encode it for that increment and have the info on frames per thickness in the file info. I can even see this type of print encoding being use all the way down to the atomic level and even being able to use color coding of atomic items for element to be placed.

Another benifit (though some may disagree) of using this kind of encoding methoud would be for future comercialization purposes of objects, I understand that the subject tends to be a sore spot for many reprapers but lets face it. people like to get paid for doing good work. so, what i mean by this is if a comercial company some time in the future has a product that they are selling, they could offer the purchase of the item directly to your printer through a live stream very similar to on demand movies.

wheither we want to deal with this issue right now or not is irrelevent. eventualy it will come to us so at least considering a way to deal with it in a open and objective fashion would be benificial.

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Another benifit (though some may disagree) of using this kind of encoding methoud would be for future comercialization purposes of objects, I understand that the subject tends to be a sore spot for many reprapers but lets face it. people like to get paid for doing good work. so, what i mean by this is if a comercial company some time in the future has a product that they are selling, they could offer the purchase of the item directly to your printer through a live stream very similar to on demand movies.

I see several issues with your concept:

1) As long as the printer is open source, and can be built by a hobbyist, protecting your design from the consumer is impossible. Even if the data stream is encrypted, it has to be decrypted before it goes to the printer, and can be captured at that point.

2) By using a proprietary format, you prevent the user from customizing the object to match the particular characteristics of their printer. As an example, any 2 Mendel printers will print through holes at slightly different sizes - the way that users generally deal with that issue is to modify the geometry of the object before printing it.

3) MPEG is a lousy format for encoding vector based artwork. It moves bits of each frame around, and introduces other artifacts which would badly affect print quality. Also, it would make distributing the object require MORE bandwith, instead of less.

This type of encoding would not work for a reprap mendel/darwin style printer, it would only be sutable for a uv curing full layer transfer method. You wouldnt be sending vectors or line segments for printing, all of the slice and preformating would be done before encoding as a mpg and then the slice video is played with essentialy any mpg/dvd device. The reason I was saying it could be potentialy used as a commercial format is if a designer created a dvd/blueray disk or had the design on a youtube-like pay per play site they could actualy charge per print. I understand that some may disagree strongly with any kind of proprietary or closed designs but open source and closed source can live in harmony. If something is worth paying for then its worth paying for, if its not worth paying for then create your own design. I admit that there are potential issues with the idea in general so Im not expecting anyone to jump on the bandwagon, this is more of a project im working on personaly and am interested in any feedback I can get from the community.

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I admit that there are potential issues with the idea in general so Im not expecting anyone to jump on the bandwagon, this is more of a project im working on personaly and am interested in any feedback I can get from the community.

Actually, it doesn't seem like you're interested in feedback. None of the points I brought up were arguing the morality of copy protection, but are instead issues that you would have to solve in in order to implement the kind of copy protection you're discussing.

I've worked in the software industry for 30 years, and have well formed opinions about the futility of copy protection. Note that I said futility there, not morality.

It has been my experience that the only sort of copy protection that actually works is the sort used by online games, where the game doesn't work if the user stops paying for it. Every attempt that I have seen to apply copy protection to a complete product (Offline games, DVD-Video, Blu-ray, etc...) has been defeated within a matter of weeks.

The argument of using an mpeg file to transmit a design is a little confused for the following reasons.

1) Data in any form can be encoded - transmitted - decoded securely, its done millions of times every day. Its also hacked now and again, this is a different argument. Choosing a video codec to transmit this type of data is like choosing a sock to carry water.

2) Most modern video codecs including mpeg are lossy (data is lost when compressed and decompressed). You need a lossless codec. Read a little more about keyframes and lossy / lossless codecs and you will understand that what you suggest is a bad idea.

3) The video images change frame to frame. Most codecs have a keyframe now and again then log just the changes to the previous frame. You only need one keyframe at the start. Most layers will be identical, so most of the time you would be transmitting a constant stream of the same image. This makes the file enormous when it doesn't need to be.

4) Your image is black and white. You will be wasting most of the transmission sending colour, keyframes, blank audio etc.

5) Say at 25 frames per second in your file you would send 1 micron layer per frame. So in 1 second you send 25 microns. 40 seconds per mm. 66.66 minutes for a 100mm tall part. In other words around 1 CD of data per part.

Ok
first raldrich sorry if i either misunderstood or misinterpreted your comment and yes i really do want input. MPG format really is just a initial idea/concept opener so its not something that I'm emotionally attached to. I only say that its how i intend to do a initial implementation, if it doesn't work well then ill retry using something like a slide show with the slices as b/w bitmap or some other graphic format. I just think that doing it that way will take up way too much space. as to the copy protection part, again that isn't something that i have any emotional attachment to but I understand that at some point the issue will have to be dealt with in a proactive way.

Martin, do you know of a video frame encoding method that would solve the issues that you mention, the reason I am looking for a video format is the nature of the print system is more like video than anything else. again love to hear suggestions.

oh, just reread your second comment and say that your analogy to a pay to play video game system is quite relevant to the concept as I see it. I agree that if you sell a dvd or a blueray type disk eventually someone will figure out a way to copy it. I really was meaning something more like a pay to print youtube type data transmission system, where stripping out the data en-route would be at least prohibitive. I almost said impossible but accept that impossible is a null set.