I come from the game industry and this is my first time creating a jewelry model for real production, so I would really appreciate some professional advice.
I designed a piece and sent it to the casting workshop. The current weight came out around 22 grams, but I need to reduce it to approximately 15 grams without ruining the shape or structural strength.
My questions:
• What are the best ways to reduce weight in a jewelry model?
• Should I hollow the model completely or partially?
• What wall thickness is considered safe for casting (silver / gold)?
• Is it better to use shell/hollow tools or manually redesign the interior?
• How do professionals reduce weight while keeping durability and clean casting results?
Since I normally work with game assets, I’m still learning production constraints like volume, thickness, and casting requirements.
Any workflow tips, common mistakes, or professional recommendations would help a lot.
what kind of jewellery ? a ring, signet ring, a bracelet, … ?
the rhino file or at least a screenshot would be helpful.
“hollow” - some jewellery is carved out from the side you do not see it, some is hollow…
…some stuff is cast separately an soldered together
you are sending an .stl file ? shrinkwrap is your friend for mesh data for simple thickening on complex shapes. (no need for redesign / model the interior)
minimal wall thickness → ask the person who is doing the casting for you.
… i am not a professional goldsmith, some of my clients are …
This is a teddy bear pendant (necklace charm) shown in the image.
I should mention that this is my first jewelry project. I normally work as a 3D artist using Autodesk Maya, so I am still learning the jewelry production workflow.
In Maya, the model is already hollow — I create thickness using Extrude, but this results in two separate meshes (inner and outer surfaces) and I am not sure how they should be prepared correctly for casting.
I also do not fully understand the best way to reduce the metal weight while keeping the model suitable for production.
The manufacturer requested an STL file, so I am currently preparing the model for casting.
Could you please advise:
how the hollow interior should be handled for a pendant like this?
should the inner and outer meshes be merged into a single closed volume?
and whether ShrinkWrap would be the correct method to prepare the mesh?
I can send screenshots, the STL file, or the Rhino file if needed.
Normally hollowing. But making areas thinner can sometimes the solution.
Depends on the piece. For rings, I usually hollowed out the shoulders of the ring (upper left and right sides of the shank). For pendants and earrings, I usually hollowed out the back.
Typically 0.8mm. But for an earring, you might try to go thinner…maybe as low as 0.6mm in some cases if you can get good results…but if you have a boss or shop manager, you should discuss this with them…where I worked, I was able to experiment if needed, that might not be an option in every shop. Casting is a labor intensive process.
I mean, you can always try shell, I usually did try it, but it normally doesn’t do well except in the simplest of objects. So I normally had to manually design the hollow. Sometimes the bad shell result could be a starting point, sometimes surface offset was a good starting point, and sometimes I had to just build the hollow completely from scratch (offsetting curves is normally the starting point in this case).
And this isn’t about hollowing, just a general thing…for complex designs, sometimes it’s easier to design flat and use flow along curve or flow along surface to get the piece wrapped around the sizing circle.
Below is a list of youtubers you might like who focus on jewelry cad (including me, but I’m not a prolific poster these days). There some other good ones out there, but I can’t find any of them right now because none of us can keep up with PJ Chen. He has posted so many tutorials.
“This is my first time making a jewelry accessory. I modeled it in Maya. I created a hole from the bottom and used extrude to hollow it out, setting the inner wall thickness to 1 mm. In Rhino it showed around 12 grams, but after mold and casting the final weight came out as 20 grams.”
Thank you. I attached the images. How should I hollow the interior correctly? The model shows 13 grams in Rhino, but the final casting weight comes out as 20 grams. What should I adjust to match the expected weight?”
If you do not care about the back surface, a weight could be removed by simply subtracting an extruded shape, but that will not follow the contour of the front surface. Removing part of the back surfaces and then thickening using as @Tom_P has suggested would be a better method.
I modeled the same piece in Maya. I cut it in half and used extrude to hollow it. In Rhino, the weight shows as 12 grams, but after casting it comes out as 20 grams. I think I’m missing something
How are you calculating the weight in rhino? Post your formula and your material specs.
Rhino or at least V7 doesn’t do weight analysis. You have to know the specific gravity of the material and then use a formula.
RM
Nice model! Normally only the front half of such a pendant is made and the back is flat and hollowed out. If you make it full like that, it will be heavier and might be uncomfortable to wear. Also, if you go with the “full” model, because of the hollow, it would need to be cast as two separate pieces (front and back) and then those two pieces would need to be welded or soldered together. I usually would make a little keying or registration system to make it easy for the jeweler to hold the pieces together correctly aligned. (I used three little spheres in this example…one at the top of the head and one in each foot).
The shrink wrap tool was not available when I worked in the industry, so I’m not used to using it. It looks like it would have been very nice to have had, though.
As a separate issue, I’m a little worried about the grunge details (the pits, nicks, cracks, and scratches). I’m not sure how those will turn out.
