converting designs

[slimey]

I use to use gem cad for this, but as I can't get datevue to work I'll have to find another way. Say i find a design that I would like to cut but it's printed with angles for quartz but I want to cut it in sapphire. Now to the Question is; there a formula for converting the angles? I know that there is John West's angle worksheet out there but a formula that I could plug into a spread sheet and change the angles that way.

[RoughCreations]

I would be very tempted if I were you to splash out and buy GemCutStudio if you don't already have it, it is a good investment to use in your craft. You will have to enter the design first if you don't have a .gem or .asc file, I have found this very easy using the 'Arbitrary Mode' in the software. You can optimise the design for any RI using a great visual tool. You will probably get much better results to apply to your valuable sapphire rough than a hit and miss manual method, particularly for more custom designs.

Another option if you can't justify the purchase of GCS at this stage is to upload the design to the Forum if it is open-source and has no copyright issues. In this case there would be people on the forum willing to do it for you, myself included as long as you don't mind publicly sharing the final design.

RC

[slimey]

Thanks for the offer, but I what the formula to do it with a calculator, as there must be a conversation formula or gem cad etc wouldn't work

[MakkyBrown]

Hello Slimey,
https://usfacetersguild.org/gemstone-design-conversion-using-the-tangent-ratio-method/#:~:text=A%20mathematical%20procedure%20known%20as%20tangent%20ratio%20conversion,indexes%20%28critical%20angles%29%20and%20degrees%20of%20color%20saturation.
But it is just not worth it. Better to get GCS so you can visually see the results as you change the angles. Just using critical angle as a basis to optimize designs will really be hit and miss.
You could use BOG, it was free, but I am not sure if Tom Herbst still has it to download but it was massively error prone and frequently crashed. The GCS optimizer has been based on BOG.

CheersMB

[Alaskan]

Finished the supernova - just now off the dop and my shed roof is leak proof... happiness is. Will start another with an African Garnet.

[FlashGP]

Hi Slimey,


Robert Strickland retired and made Gemcad and GemRay free.  Download GemRay and use it to optimise for the RI.  Put a minimum table change restriction in the settings as it tends to lower the table to increase brightness.

Then enter the new angles for the pavillion row and crown row shown in GemRay into Gemcad by editing the relevant row.  This will cause Gemcad to tangent ratio adjust the remaining rows on the pavillion and crown.


I have both the Gemcad/GemRay suite and Gem Cut Studio (GCS).  Used Gemcad for years before GCS was created, but GCS is my goto programme, it’s easier and quicker to use and has a built in optimisation routine.  There is only one feature in Gemcad that GCS doesn’t have, the feature to calculate an angle to make the facet edge run at a right angle for cutting checker tops.  GCS you do this manually by adjusting the slider for the angle.