The 3 attachments are representations of a horizontal tail for a replica of a 1938 world speed record attempt airplane.

The planform is not a trapazoid like the wing planform tool in AeroPack, they represent a realistic planform with rounded tips.

The skinning was done using the two rail sweep tool since there is not an airfoil per-se at the wingtip. The skinning is unusable. What's going on here?

The first attached tail is with the leading and trailing edges as control point splines, the second is with them as interpolate splines and the 3rd is with bezier splines. None of them are satisfactory.

Am I doing something profoundly wrong, or are we looking at a problem. This should be a very straightforward task.

A late reply to thread (well, I am new here), but wanted to show a solution.

The problem appears to be due to the amount and position of the control points on the rails used for the sweep(wing_tip_01). I did (quickly) re-draw the rails, and made the sweep again, and without problems(wing_tip_02)

Hi jol,
I do think the simpler the cross sections/rails can be the better (for any nurbs package), but it is the first time I have really taken time with acis kernel, maybe it is a little particular on control points, but I do stay minimal (with control points) with all nerbs apps when building surfaces. I am not actually sure that it is the kernal that is in control of the sweeps, I am a little lost in that area (I like to build models, I cannot build these types of programs lol)

I will be around quite a lot now (if OK) as my only real problem is with which version (pro/shark) to purchase, and I do like interaction with other users.


Regards,

- Steve

I see where you are coming from now Steve! Sorry for that confusion earlier. This is a wicked tutorial- thanks a lot for posting- it makes a lot of sense too!

What's that term again...."Knowledge is power"? :rolleyes: :D

Tom :)

I gotta say chaps, that I too really love the community here (as you can probably tell? ;) I also tend to love internet forums- its a great way not to do any work!! hehe!).

It's a shame that the bulk of my models to date have been made in Solidworks, otherwise I would have posted by now. But I guess I've just gotta get cracking with VC, and upload some stuff- all in good time. :)

Hi jol;

I do see that they have split the ability of surfacing over the various products.

The surface over 2 rails is limited, as it appears only possible to use 1 cross section, the option for a group is a little confusing, does the "group" mean 1 cross section of a connected group of objects? If I attempt multi cross sections, then I get a "unknown error" popup.
Yes, there is the skinning with rails and also net, but I need to check/compare the surfaces created by those.

As long as you dont get strange popups of errors.

For a "net" (which I presume is a "network" or "boundary") surface, then I would normally expect a G2 surface, but that can cause bulges. It is sometimes preferred a forced G1.