CAD question?

Hi

I have been working with Cinema 4d and 3D Studio Max before, when I was a regular 3d artist.

But now I want to try out CAD models.

So I got some "First time questions", That I need answered. So guys please help me out

1. Is it any different if I model in Polygons and print it as a STL file? Or must all the "products" be made with CAD softwares?

2. Does 3D Studio Max uses for Cad modelling? I have nurbs features.

3. Whats the different to use a Polygon File extensions format instead of a Nurbs format? Will my product will be print wrong? (if I use polygon).

4. Does all model with CAD? Can I model with Polygon to get the same result?

Thanks! for the help!

/John

Based on your questions I'm going to guess that Autodesk Alias or Autodesk Inventor might be a better choice for your 3D "art".

Students can download these Autodesk products for free from http://www.autodesk.com/edcommunity

You might watch some of the classes (in AutoCAD mesh modeling, Alias or Inventor) here http://au.autodesk.com

Hi

Thanks for the fast reply!

But I can model in Cinema 4d or 3D Studio Max, Is it a must to model in Nurbs?

Or can I use polygon modelling and use it as good as Nurbs? Will it be any different of the end product if I use Nurbs or polygon? or is it the same printing result? just a different teqniue.

Thanks.

I think you must use NURBS modeler for engineering/manufacturing purposes.

But I am confused by your "is it the same printing result" statement.

Are you referring to 2d paper prints or photographic type output (digital or print)

or

are you referring to one of the Rapid Prototyping/3D Printing/Additive Manufacturing processes (stl)?

Lets say I`m modeling a "product" for production, That will be send to manufacturing printing process.

I can`t model in AutoCAD, but I can model Polygons in Cinema4d and then save it from Cinema4D to a .STL file.

Will this work? or do I need to learn AutoCAD and model in Nurbs to get the manufacturing process correct.

What I mean with the "printing result" is: Will it work? or dont the manufacturing allow .STL Polygons?

Thanks!

Or does some manufacturing works with polygons and some not?

Maybe it depends which manufacturing who prints it ? Some allowes only Nurbs (Then I must create it with Autocad), If allowed Polygons (I can use Cinema4d),... Am I right?

If you can save the file as *.stl file type then it should be usable by the RP machine.

Post an example here of your *.stl file.

I have attached a Test.STL.

Its a sphere with booleans, That I saved as a .STL from Cinema4d.

Test.zip

Looks good to me.

I recommend you increase the facet resolution for a smoother model.

Let me do some testing with this model tomorrow for final verdict.

So my model works fine for manufacturing print? Why dont People model in Cinema4d and then save it as a .STL then? This is much easier instead of learn AutoCAD.

How much resolution should I use?, Until its very smooth?, can it be too much?

Do I need any unique scale? Lets say it much always be in millimeters.?

Thanks for all the help btw!

Not used for manufacturing because the stl model is not smooth - it will always be faceted.

Would you purchase a car, or cell phone, or diamond ring that had only planar faces?

Oh, OK for the diamond, but it should be obvious for the rest.

RP models (*.stl) are used for early prototypes, not generally for production parts.

No matter how "smooth" you make it - it will always be faceted and layered when made on the RP machine.

Different machines have different resolutions.

I always set my stl files to "Fine" or highest resolution - there is a trade-off on file size, the smoother the resolution the larger the file.

But at some point you also hit the resolution of the printer - generally not very good unless you have access to a very expensive (>$500k) machine.

Imagine manufacturing something as simple as a cylinder.

- as stl file the machine would have to mill individual tiny planar facetes.

- as true cylindrical geometry (extruded cylinder) the lathe simply turns the stock as the tool moves linearly.

I recommend you sign up for a basic machining class if you want to continue in this field.

I worked out on the shop floor for 8 yrs as a machinist and it always bothered me when designers would design some feature that couldn't be manufactured or manufactured at a reasonable cost or that a customer wouldn't look at and consider garbage.

So I can`t use .STL for manufacturing? (because its not smooth polygons)

Then I must use Nurbs in AutoCAD, I guess. (with smooth curves)

Am I right?

Am I right?

Would you purchase a car comprised of only planar faceted faces? (similar to the "sphere" I posted earlier)

What products (other than diamond jewlery) would you purchase that was all faceted planar faces? (there are many products that are only planar faces - a box for shipping a product might be one example)

What products would your customer purchase that were all faceted planar faces?

Hey, where did that image go? For some reason I no longer see it.

Hi again

So the answer is "Dont use .STL for manufacturing", Because I dont want flat planes. Which format shall I use then to the manufacturing? Whats it called with Nurbs?

I did some search on Google, and found this. Its how to use .STL for manufacturing.

There it says its about the resolution how smooth it will be, (I guess it will still be flat plans, but then very small, maybe it works?)

http://redeyeondemand.com/CADTOSTL.ASPX

I also found this.

http://www.c4dcafe.com/ipb/topic/57686-c4d-for-manufacturing/