AFG 2024 Annual Competition

[FlashGP]

Hi,


After 7 months or preparation the competition schedule for the Australian Facetors' Guild 2024 Annual Competition was released last weekend at the AFG's  Muster.  The competition schedule can be downloaded from the AFG's website.  [size=78%]https://facetorsguild.com.au/page-18120[/size]


Andrew Brown created a new version of his Tiger Yin Yang for the competition, and I am delighted that he has donated 3 of his faceting design books as prizes for the competition.


We have included a concave section again this year, but it should be a little easier than previously and I have included a twist in the design.  I dare say it is a bit of a hybrid cut as I have included frosted boundaries in the design.  It has some low pavilion angles, but the rules allow these to be changed using the tangent ratio  method.


regards
Gordon Perkins for the competition committee

[FlashGP]

Hi All,

It's with regret  that I have to inform you there was an error in the design we published for section N.10.3 of the competition.as Andrew's Trioptic Blast.  Andrew, on behalf of the competition committee, please accept our wholehearted apologies for the mistake.   It's a case of the committee not seeing the woods for all the trees.

An updated competition Schedule containing the correct angles is now available from
https://www.facetorsguild.com.au/resources/Documents/2024%20Competition%20Schedule%20-%20Release%202-Copy.pdf.
Chose the file labelled Release 2. 

When the design was entered into Gem Cut Studio to allow all diagrams in the competition Schedule to be presented in the same format, the C1 angle doesn't appear to have been added, meaning that the last angle used (P3) was used instead of the C1 angle.  This meant that the C1 facets didn't meet the table and the shape of the C2 and C3 facets was changed and the Committee didn't pick this up in the several revisions of the schedule checked before publication.  The published schedule was actually revision 7.

Luckily the Competition Coordinator agreed we could update the diagram, but entries cut to either diagram will be accepted to be fair to entrants having already cut an entry using the incorrect diagram.  The statistics for both stones are in substance the same as the table height and dimensions are governed by the C2,C3,Table meet point.

The other, but not as nice solution would have been to re-label the incorrect diagram something like "Committee's Mistake" or "Ah Whoops", which in my view isn't as appealing as Andrew's design, although the optical performance is very similar due to Andrew's pavilion design and the height of the Crown.

Entrants who have not finished cutting their entry for section I.10.3 now have the choice of finishing the stone as is or lowering the C1 angles to the correct  angle so the C1 facets meet both at the C1,girdle meet and the C2,C3,Table meet.

Regards
Gordon Perkins for the 2024 Competition Committee

[Ghost]

Hi,
 Are you talking about I 10.3 or N 10.3?

[FlashGP]

Hi Ghost,


The Novice stone, section N.10.3 Trioptic Blast


Rather embarrassing as we circulated 7 revisions of the schedule to members for checking before publishing it and I didn’t think to check the design matched Andrew’s design.

[MakkyBrown]

Thanks for making the corrections Flash,
Cheers
MB

[FlashGP]

I was worried we wouldn’t be able to make them, but by allowing stones cut to either design overcame this.  Luckily the reflections of the pavillion through the C2 facets is sufficiently similar that the visual effect score shouldn’t be affected. 


I had initially suggested Fred Van Saint’s Halve a Heart For the open division, but the Gemcad diagram didn’t translate to GCS well and even in Gemcad it was hard to get the meets in place.


  I even tried creating a preform so we could position the cutlet outside the edge of the dop.  It didn’t work.  Hans cut away part of his dop trying to proof cut the design.  We ditched the idea.


It seams the two cad programmes don’t like positioning the cutlet on one edge of the stone and off centre.  It really shows up when you mirror the design to cut the other half.


Now the schedule is published I can discus the issues with Rej.

[MakkyBrown]

I will redraw the half heart for you when I get time.
CheersMB

[FlashGP]

Thanks Makky, I’ll be interested in seeing how you go. To show the detail in the side view when we reverser the direction of the index wheel to create the other half, we ended up having to say the Crown was the pavillion.


I initially tried to create a preform so the cutlet was a known distance off centre, 0.7w, to allow a 1/4” dop to be used to cut a 10mm W stone without cutting away the dop.


This is when I ran into real trouble with GCS.

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