Yaron [LaserOp] Posted October 24, 2019 Report Share Posted October 24, 2019 (edited) This is a continuation of a few related topics that were previously discussed in emails (involving Me, Paul, Christian Laurent, and Robert Shanbaum), and mentioned on the last VEW meeting. Since there are potential interested (and contributing) people outside of the email thread, it seems better to transfer this to the forum, so it will be possible for other members to view, and contribute, to the discussion. Apart from #1 I don't have personal stakes in the matter, except for the confusion that can follow from #2, which at this point is solved for me outside of the DCS document. So answers/discussion on #1 are needed, it's an open topic. For the rest I think it's a good idea and important to handle, but they were possible discussed on VEW, so if everyone else is happy... 1. Engraving Reference for front side engraving All of the above was for back-side engraving/marking. What about front side? I strongly believe it couldn't be ER as-is, since there should be only one ER per lens in concept, it shouldn't change based on whether it's wanted for front or back (and it's not even possible to always tailor it even if a VCA Host wanted to). On the other hand, so far in practice from our customers, whenever front-side/finishing engraving isn't done relative to frame (which it usually is, so doesn't matter so much), they expect it relative to FB. But from Christian, they report to use the PRP (Reference Point OC) as center for marking on the front side on a finishing block. (So difference of FBOC__ ) So there are at least two different practices already in practice, and none of them actually says "Engraving" for when describing their Reference Point. There should be an explicit decision in the DCS. Is there to be a different new Reference Point? Should it be standardized on OC (and so the description of OC should mention it explicitly, or it should be mentioned explicitly in Marking Records)? Something else? 2. The new BE Reference Point, name The new BE point ("Back Engraving Reference") is intended to be found from inspecting marks already engraved on the back side, and for PRP / OC to be derived from it. So I think the name and description is currently incorrect and very confusing. "Engraving Reference" very much signals, on clean reading, it's going to be the reference point for engraving, not that it's a different reference point to be gleamed from engraving. 3. The new BE Reference Point, not commutative with other Reference Points, so should it be one or a different record? So far the list of Reference Points are, to my understanding (?), commutative. SBBC__ + BCOC__ = SBOC__ , etc... This would work even for connection labels not officially on the standard, I assume, so probably various LMS/VCA-hosts would be happy to "calculate" one if asked for. But BE doesn't, because it's only useful to find OC, and required the additional BEOCA beyond the normal UP/IN sets for all other Reference Points. Since the usage, and potential errors, are very different from other Reference Points, maybe it shouldn't be on the list as a Reference Point? Or at least there should be something very clear in the definition to separate it. Alternately, maybe I'm just wrong about the assumption of commutativity? Is FBSGIN - BCSGIN + BCOCIN = FBOCIN ? And SBSGIN - BCSGIN + BCOCIN = SBOCIN ? And so then FBSGIN - BCSGIN - SBBCIN is the correct equivalent of FBSBIN ? If yes, then it's a really really strong case that BE (or whatever it should be renamed to) should be differentiated from the Reference Points lists. It's a lone position that doesn't fit and doesn't behave like the rest. If no (probably since SB and FB aren't on a parallel plane, so "- BCSGIN + BCOCIN" isn't valid from one starting position), then there is already a big problem, and which label is valid in which case is very much not clear from the list of Reference Points. So the Reference Points themselves have to be clearly and explicitly split into the different sets/groups, to it will be possible to get from the DCS which can't, and which can't, be connected. Edited October 24, 2019 by Yaron [LaserOp] Removed a few of the topics that were already closed on the email discussion, and were here more for info than need for discussion. Made the post seem too large and complicated, which could have reduced participation instead of getting it. Quote Link to comment Share on other sites More sharing options...
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.