Alias Interior Modeling – Gear Knob

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This is a component which was set as an interview test for one of my students.

He is know working for a Major OEM.


It may look simple, but there is nothing easy about surfacing this type of complex volume.

Where to Start?

Always start with a Y=0. curve-set, which has G3 crv. crvtr. and then from the Sectioned crvs. project draft srfs. in the +Y direction.

Spheroid in Shape

Analyse the nature of the form and you will realize , that it is basically a Non-Prop. Scaled sphere, which merges into a cylindrical base. I know that to avoid any triangular patches I need a Cap-Surface, which will give me a true surface to run my Blend crvs. from.

Once I have the Cap-Srf, I then trim it to the shape I need in F5, then I mold a Planar Srf. 5,5,1,1, to exactly fit it. this gives me my first surface, which is also Bezier.-

This view shows a student’s work

but whilst it’s a great concept model, only 2 of the 7 srfs. are Bezier, so if your end-user wants A Class srfs. there is loads of work to be done, to get it from what is shown here to Bezier.

Below are 2 shots of my own Bezier model

This would be made with Nurbs srfs. in Industry.

It might start life as a clay model and then be developed between the Hard Modeler in plastic and the Alias modeler. The designer would want to make changes until He/She got the shape and the highlights exactly as required. I modeled an Audi door mirror for a Czech. Republican designer and he asked for it to be modified 30 times before it met both Design and Engineering criteria

Highlights are looking really nice

but there is still work to be done on the nose, where as you can see the HL’s are not perfect. A prototype or a Styling model would be made and the faults removed by a highly skilled Hard Modeler, then the Alias modeler would be fed back the scan data.

Of course this component would be finished in hard wood

or leather and not as I’m showing it in Car Paint or Chrome, which really shows up all the faults

Students following my Alias training course, learn all this workflow from my unique video tutorials.

Hallo all Alias students,

OK. I will show you my points. I have been making 9 surfaces on the LHS. of the model and they are all Bezier.

I am modeling this in single span, so that I’m really learning how to control Bezier srfs, to the extent that I can get them to comply to any shape with Catia V.5 tolerances. It has taken me a long time to get this right and Graham is helping very much, with videos and tips. I think in a Design facility, this would be made from the scan coming from a hard plastic model perhaps and being made B4 that in clay and my job will be to make a Nurbs model of it , which is also incorporating the Designers changes.

Finally : I have learned so much about how is making precise Bezier srfs. to CV5. and I am now much more confident about taking on any Automotive surfacing challenge. B4 signing-up with Graham, I never had any clue about working to this high level in Alias

Enjoy your Alias.


Karen Mayer (Advanced student


Hi, I am Kevin De Smet

Here’s my model of the same gear knob. What makes this shape interesting for study, is to model it all bézier and make it 1. smooth and 2. closed, I have found an even better understanding of how control vertices influence the tension of a patch. In the middle it is also easy to be lazy and make an “S” shaped surface, but as best practice dictates, it was a nightmare to control! Finally, the zebra plot I think gets a lot of discredit sometimes just because it is so liked by beginning modelers but I disagree as it shows the flow (remember: i said flow, not highlights) and strakness of the surface quite well, together with double horizon and visual curves for highlight analysis I get a lot of feedback on the quality of the surfaces.

In industry I would model this as 6 nurbs surfaces, and considering it will probably be covered with cloth, there is no need to bring it to this high of a level in a production environment where time = money.



Kevin De Smet (Advanced student

Students often ask me if Interiors are easier than Exterior to Model

Well you dont have to worry about getting good highlights on large surface-sets, but on the other hand, you do have to work on forms that are more difficult to conceptualize + you have to be very good at building complex fillets quickly. I don’t think one is easier than the other.

Q) Once you have committed to be either an Iterior or Exterior digital Sculptor, aren’t you stuck in that discipline forever?

Ans) No not at all Exterior Modelers are often given Interior projects and Interior modelers, as long as they have built a few Exteriors (At Uni or by practicing at home ), can make the change to Exterior work

If you are interested in learning Exterior/Interiors , please email me for course details

To Learn Alias Automotive to Industry Entry level has been made easier.

For student’s who have the objective of finding a CAD job in the near future, I still teach One to One students and all of these students get Automotive Modeling or Design/Modeling jobs, so it’s a great investment to make. The hourly rate is very high and there are vacancies in UK. France, Germany, Sweden, Spain, USA, Brazil etc. I can only take a maximum of 5-7 students at any one time. I teach all levels right up to Post Graduates. I have never had a Private student fail to get an Alias Automotive job (Companies include Ferrari, GM, Lotus, Opel, Audi Seat etc. ). If you wish to apply for a place, please email me with all your details.
Why not visit my website and take a look for your self?
Over 100 videos on many, many aspects of Learning Pro. Alias
I show you how to build a Complete Audi A5 Sportback (ext.) . Over 50 Videos on that alone !

Info. on Courses:

“Course #1”.

6 Months website access to all website based video tutorials, 167 Euros (215 USD equivalent Sept. 2012)

“Course #2”.

167 Euros (215 USD equivalent Sept. 2012) per month. You get your .wire reviewed by me every 15 days and you will receive : feedback, instruction, tips and advice from me personally. Access to all videos including my ” Private Student Training Videos”. You will build at least 3 complete automotive exteriors. The course also includes an intensive Reverse Engineering section, which required by most employers.

“#3 Full Pro. “Elite” Course”.

Fast Track Full Pro. “One to One” Course with weekly reviews and coaching 200-250 Euros (USD. 260-320 approx. Sept. 2012) per month. One to One Private tuition. You will receive specific geometry and meshes and modeling from me personally where required, to help you to complete your exteriors quickly to an Industry entry level standard. This means a bigger investment, but once in an Alias modeling job you will get back what you invested many times over and be able to work anywhere in the world

NB: Typically students pay 50% of the cost of the “Elite” course by monthly installments settling the balance over time,  once they have an Alias Automotive contract.

For more info,

Just register on my website and I’ll send you all the details

*** Special 25% Discounts for US students (Message me on my website for details)


If you are in the USA, just register and login, then go to Profile and you can pay your subscription with your US credit card. Absolutely no extra charges for currency conversion.


Graham Bullock B.Ed.(CNAA)Des.Tech.

Go to Learning Alias

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