Seeking Master Organic CAD Modeler

[Anonymous]

I am seeking an expert CAD Modeler with skills in complex organic surfaces.

I hired a very skilled CAD designer to create this model in Alias: https://mikefieldsbronzes.com/portfolio_page/swan-modern-sculpture/

He does contract work for car companies. He was able to import my obj and begin work, but after 140 hours of trying to reach my level of perfection, he ultimately failed. 

I created the polygon based master in Modo. 

Attached is my my order. 

 
This piece marks my entry into the contemporary art domain.  I am leaving behind my successful career as a traditional scultptor. My entire career depends on getting this piece produced at the highest standards possible.  It will be very costly to produce flawlessly in stainless steel and the master CAD has to be perfect first. 

If anyone knows anyone anywhere that can do this please let me know.

Thank you,
Mike Fields

[Anonymous]

My correspondence with the previous designer:

Hi Mike,

I've tried to answer your questions below. I hope this helps:

1. I'd be wary of anyone who doesn't do single span, low patch models. What is the simplest way I can specify and check if a modeler is using the cheater approach? I need to require: “A class, Single span, low patch model with G2 Curvature” & “all curves need to be constructed such that they maintain continuity across mathematically precise subcurves” How can I confirm this was done properly?

I don't know how you could check without Alias to be honest. I do not know if other software carries over the isoparms. I think if you find a modeler who is happy with what you specify, he wouldn't pull the wool over your eyes. You'd figure it out long before the final model I would think.

2. Why do the triangles matter, given that it is being completely rebuilt with a different logic/math/approach? Should I try to eliminate these in the master? The model is really not built very well, with terrible end caps etc.

It doesn't matter really, as you say it'll be constructed in a totally new/scratch built way. It's just the way that is done is extremely tricky and time consuming. Maybe specify with the next guy that the end caps can deviate significantly in order to have nice surfaces. These will be tricky because as you say, you're no longer using the "real" mathematical boundaries so fillets and ball corners around those areas become infinitely more complex.

3. Are there fillets or radius along the length of a rail? Why? Can’t these just be defined in the cross-sectional curves and run along a rail? Can it be made like slices of a banana stitched together instead of like the peels of a banana stitched along the seem? Hope that translates😊

I understand what you mean, but I don't think Alias is the correct software for this sort of construction. It can be done using a method called "curve networking" but the surface quality is often extremely low and it results in very large amounts of patches and or isoparms. I was once given an interior model modeled in this manor and I had to restart from scratch as the data was useless for anything other than reference. 

4. Were you able to create cross-sections with mathematical precision? I just want to confirm that I can tell the next candidate/victim that they can use them without checking em.

It's very easy to create sections in Alias using the X Section tool and I simply used that, and your sketches to get somewhere near. I didn't create the sections as such, because as I said above I don't do curve networks. So it was a case of referencing what you had in the mesh model with the sketches and then tweaking my surfaces. I also think you should allow some small deviations from your drawn sections for the sake of highlights working nicely in 2 dimensions.

I hope that makes sense I'm not so good at explanations unfortunately haha!

Thanks very much for the kind words, I really appreciate them. As I said I do hope we can work together in the future and don't hesitate to get in touch if you need any help with the final surface analysis etc. I'm happy to help in any way I can. I appreciate your professionalism throughout this whole thing and I hope you stay in touch. We definitely share similar professional attitudes I think and I always want to deliver my best work rather than send out sub par work for the sake of a cheque! 

The model is attached (in Alias format for the next guys as to keep layers etc). And I think it will be very useful to the next modeller. Even if they only use the mesh it's all trimmed, separated and positioned correctly which saves significant time and effort.

[rossbau]

In order to help with the problem I first want to emphasize on getting desired quality.

Achieved quality in the CAD model is NOT a guarantee that the final physical outcome is in the same quality.

I recommend to ensure that the CAM-process is superior and can output quality.

I would rate the importance of CAM higher than the importance of CAD. – see the entire process, not just CAD!

The model doesn’t need to be single span. The modeler just should care for an even placement of those segments. It is not good to have a concentration of segments only in special areas of the patches/curves.

The model should be checked with curvature combs along the feature lines as well as with curvature combs on sections trough the final model.

To judge the curves ONLY curvature combs on the curves should be used, especially many curves and their transitions!

In order to check for multiple segments the user can use the check-model tool-evaluate tab in Alias-automotive and Alias-surface only!

If the model finally should be shiny (covered with chrome) then its highlight quality is important. Such highlight quality can be achieved using NURBS surfaces rather than polygons.

That’s why Alias could be a good software to realize the idea.

I suggest the following way:

The idea of the swan will be communicated with the MODO-model. Alias will create and refine the final model. The Alias user needs some freedom with the end caps to make good surfaces. The MODO-model only gives basic dimensions and shape of the feature curves. There is no compromise with this. The Alias modeler must keep this!

The model should not be done with only one surface that is sculpted but with a network of patches. Curve network is not a good tool for this, because it cannot give the desired quality.

The model will be with slab surfaces (big surfaces), blends and fillets. It will be a patchwork of surfaces.

Allow the alias modeler to deviate from the MODO-shape is cases he can argue this, not in general!

To find good modelers it might be helpful to find as well rhino-modelers. Everything I said above is here valid too!

[systembolaget]

The Swan model is, in terms of form, fairly straightforward to do in Alias and other CAD packages (as far as what one can tell from the images on your site).

But the inevitably subjective "level of perfection" is hard to specify in contractual terms; perfection means different things to different people and also very much depends on the production processes involved in physical realisation.

When, for example, models will be milled for, let's say, sand casting, the milled CAD model will be manually sanded, buffed and coated before use, and many small flaws disappear in the process, depending on the skills of the casting company.

See, for example, what Arnold AG (Germany) goes through when producing Jeff Koons' ultra-polished sculptures. It's quite an amazing time consuming process.

[rossbau]

Hello,

yes, thats why i advice to see the entire process, even the CAM. i mean with this even the realization.

Kind regards

Uwe Rossbacher

[Anonymous]

Thank you for your detailed response. 

I see this as a series of masters.  My Modo is the design master.  Then The CAD model will be the final production master.  I understand that from here quality will be lost. The physical master will be CNC'd.  Then the lost wax process to cast it into  316l Stainless with a #8 distortion free mirror finish.  On some in the edition, I hope to CNC the Stainless Steel final product directly to ensure the highest fidelity.  

Does the CAM or CNC tool path have to be considered at the time of creating the CAD? If not, then my focus presently is simply getting the best CAD master possible, with other challenges to follow.  And yes, i am certain i need a nurbs surface and that my modo design model is not sufficient. 

I played around in Rhino myself and did some research and i am not confident that program can create the surface quality i want.  I originally used linkedin to find the designer.  Are forums my best bet or how can i find a first rate modeler?

Thanks, 

Mike

[Anonymous]

Thanks for the reply.  

I am familiar with Arnold AG.  They are currently CNCing his work out of custom billets of Stainless Steel.  

I see your point in regard to perfection.  However, as far as surface quality is concerned it seems there are standards, even if Class A is not the best term.  Since it will be high polished in the end I need the surface reflections not to get pinched or distorted on the small and large scale.  If i grid were reflected on the surface i want it to reflect in a clean and predictable way.  And, yes, for final product quality, Koons is my standard. 

Sand casting is not an option.  As far as quality it would go: Direct CNC, then, Fabrication (cloudgate) then, Lost Wax Casting and finally Sand Casting.  When i can afford it I want to be able to directly CNC the Stainless Steel to avoid pinholes, distortion and to have flexibility in sizing of each unit in the edition.  

Any suggestions on finding an expert modeler?

[systembolaget]

No suggestions, sorry. I would think any surface modeller working for a top-tier consumer goods or automotive company should be able to do the job.

[rossbau]

HI,

I cannot agree more!

Best wishes

[rossbau]

Hi,

Any surface modeling software can do it. Alias can do it, others too. you research should depend on the operator you can find.

There are specific requirements the manufacturing method needs. If you oversee the entire process you can care for them at the beginning.

Sir, you can invest too much money into the CAD model since in manufacturing the quality cannot be achieved or simply by hand sanding it will be achieved anyhow. Please be aware that you can save money when seeing the entire process.

All the Best