hello to all. Im a student and i would like to know informations about NURBS. Specify i would like to inform me how CAD programmes generally  use Nurbs methods in api interface and which objects are using NURBS. Please tell me your opinion. Thank you very much.

Why not do an Internet search on the question "What is NURBS modeling?"

Sorry but im not ask this question. I would like to know opinions from users about Nurbs methods in CAD programmes generally. About api and objects that using. Thank you for your interesting!

You won't get many responses here if at all.  Try asking at the AutoDesk, Solidworks and Microstation forums.  You might also post the same question at the CATIA and Creo Elements forums too.
John Connor2014-05-30 13:43:54

Hello my friend. I asking here to take answers generally. About all programmes.. autodesk,solidworks,nx,creo etc. Im asking here because its a cad forum. If you know a better forum (generally about cad) to write please tell me.. thank you for your interesting!

Doesn't look like you have gotten much in the way of a response.  You might want to try those other websites I mentioned previously.

Hmm...I clicked on this conversation because although I have many years experience with autocad. I never had the need for the 3d capabilities til now. So that being said. I've been teaching myself. My question is?Can you extrude,loft,sweep,revolve an ellipse in two directions or is it three? like some appliques I've seen? If so, How?

Yes, you can extrude, loft, sweep and revolve an ellipse.  What are you trying to create?
John Connor2014-06-02 18:02:05

See ellipse block in "New blocks"... instead of creating the rafters one by one for a roof. I wanted to generate the shape and slice it...I couldn't figure out how I could do that.

You would slice it using the SLICE command wouldn't you?  Maybe I'm not following you.  Sorry.OK, I gave it some more thought.  Tell me if I am on the right track.Basically you want to create an elliptical dome with a thickness of 6.0 units (I based this on your original drawing) then you want to slice it into multiple sections of 1.5 units?

John Connor2014-06-02 19:30:20

Basically, I think? I've generated shapes before and then I've sliced them using the "Slice" Command.Then I've used "interference checking" to generate new shapes. Or make newsurfaces that are perfect!? So, how can I generate an ellipse in three directions? Mesh or otherwise, so that I may "SLICE" it every 12" with an 1 1/2" solid? Did I ask that right? BTW, Thank you for your responses!

Create one quarter of the dome using the Loft command.  That will create a surface.  Use the Thicken command next to get the overall thickness.  Then mirror and union the separate pieces to create the entire dome.  Extrude a circle through the dome and Subtract for the hole.  Slice it up as you see fit.

John Connor2014-06-02 19:59:04

Thank you, very much for all your help. But I'm just not getting it...My lack of experience and my trial-and-error technique to learning has only allowed me so much. I'll keep trying thou. The rat gets the cheese eventually, right?! Have a good one!

What aren't you getting?If you could do the 3D model you uploaded to this site then you can do this.You're going to be working with just one quarter of the ellipse in plan, front and right views.  You're going to loft the two vertical sections of ellipses and specify the horizontal section as the "guide".  That's what will create the surface.  The surface needs to be given a depth.  That's what the Thicken command is for.  Once you have one quarter of the dome completed you mirror it to create half a dome then mirror the half to create the whole dome.  Join all four sections of the dome together using the Union command.  I'm sure you can handle it from there right?

Another method to create the surface would be to use EDGESURF.  You need four edges though so take the piece of an ellipse that is the longest of the three and break it.  Once you've run EDGESURF you can then run the Mesh-to-Solid lisp found here at the CADforum to generate a solid.
John Connor2014-06-03 11:48:38

Please see 'New Blocks' For a Look @ ellipse2The 3dconstruct is pretty cool. Thanks for all your help & tips!

Sure thing.  Thanks for sharing your design too.