"Even with my very limited knowledge of mold production and injection molding, my limited experience tells me you're barking up the wrong tree when it comes to the software, process and type of equipment you think can be used to create those sort of parts."

If you don't have any experience with what is being used in the Jewelry industry, then you would not understand that there is a big difference in what is an acceptable 3d file format.

I suspect this comes down to the fact that they are using much smaller CNC machines, and are not pushing around as much mass of the machine to do the milling.

Hello chrisd,

Again, the shop is under no obligation to educate you why they are unwilling to provide a product or service. I suspect that it has something to do with your insistence that they are too ignorant of their own shops capabilities. My knowledge is limited relative to others I know that view these boards that make a living in the mold design industry. That's not to say that I don't have mold or CNC experience, I just don't pretend to know more than others on the subject, and I've found that operators are happy to provide alternatives if you give them room to move. It sounds like you haven't done a thorough evaluation of the available technology to provide you with a proper part to acceptable tolerance using an efficient and relatively affordable workflow. You can bang in a nail with just about any tool given enough time and effort, but hammers do a better job than most for that task.

"Again, the shop is under no obligation to educate you why they are unwilling to provide a product or service."

If the service provider cannot or will not explain their service, that is simply poor customer service, and IS ignorant if the service provider believes that will improve the experience.

"It sounds like you haven't done a thorough evaluation of the available technology to provide you with a proper part to acceptable tolerance using an efficient and relatively affordable workflow."

Again, not true. A machine shop tells me they cannot machine without a nurbs based file. Another machine shop tells me they can machine from an STL, but the size I need is too large for their equipment. I did not fabricate this information, it is true.

If you can draw an intelligent conclusion from this info, then you are smarter than I am. That is why I say I need more information.

At this point it makes sense to deal with the service that can handle the size, and give them the file format they require to do the work.

And I have been polite with them. What you are hearing is the frustration at this point.

I am doing my job as an informed customer, seeking knowledge about a products or services. If a customer does not get that information directly from the service provider, then it indicates ignorance on the part of the service provider either about their service, or about good customer relations. If they do not want to educate the customer about their product, what then should the customer do?

Hello chrisd,

Honestly, you really don't need to convince me of anything. If you're being treated the same way by multiple shops you have to at some point step back and reevaluate your questions and requests especially if you're getting similar responses. I'll admit that it takes patience to deal with the challenges associated with fabrication markets, but that time can also afford you some benefit by exploring your manufacturing options.

Wow Max, that looks amazing! Are the generated surfaces actual NURBS surfaces? Or just the wireframe as curves?

>>Are the generated surfaces actual NURBS surfaces? Or just the wireframe as curves?
At this moment it's just a subdivided mesh. All lines is polylines, not even curves. But it's a just a first step. I've found the algorithm which can produce exact seamless nurbs-surface based on subdivided mesh.
So, stay tuned :)

Very impressive !
eric

Cool!
So what will be the export ? If you export in OBJ : object will be segmented again by the MOi mailer ?

Max, do you have a link to the algorithm?

I came across this: http://www.cl.cam.ac.uk/techreports/UCAM-CL-TR-773.pdf

Thank you,
- Brian

Hi Brian!

I've read a lot of documents about this. The most interesting is:
http://www.dgp.toronto.edu/people/stam/reality/Research/pdf/cc.pdf
http://research.microsoft.com/en-us/um/people/cloop/qteg.pdf
http://www.eecs.berkeley.edu/~sohamum/files/cs284_f12_project_report.pdf

Hi Max, the difficulty comes with the "extraordinary vertices" - vertices where other than 4 edges are coming off of it.

The subdivision surface behaves somewhat differently in those areas and those are the problematic parts to put NURBS surfaces on.

- Michael

Hi Michael.
I am not confident of success, but I'll try to implement Jos Stam's method of calculating the surface exactly.
----

[added] open mesh support

Hi Max,

> I am not confident of success, but I'll try to implement Jos Stam's
> method of calculating the surface exactly.

Ok, but evaluating the subdivision surface exactly does not really solve the problem of conversion of the surface into a different form...

I think what you will end up finding is that regular areas of the mesh will convert quite nicely but that there will be difficulties in the areas of extraordinary vertices.

But I'm looking forward to seeing what you come up with anyway! :)

- Michael

Michael,
Could the "extraordinary vertices" be easily identified beforehand? This tool, even if there were parts that had to be "left out", would be very cool. Then using other tools to handle the extraordinary part...

Hi Burr, yeah the extraordinary vertices are pretty easy to identify, they're just vertices where there is some other number than 4 edges coming off of the vertex, see here:
http://www.multires.caltech.edu/teaching/courses/subdivision/intro/sld012.htm

- Michael

This is early beta version of my subdiv script. I'll add more features later. High precision mode (for extra smoothing around an extraordinary vertices), per edge sharpness, and more. Script supports 3- 4- and 5-sided polygons.

Hi Max, Which scheme are you using?

http://www.holmes3d.net/graphics/subdivision/

Is it going from Nurbs to Nurbs or ?

- Brian