Hey Burrman thanks for explanation and video, much appreciated.

Still much to learn

Steve

Hi Steve - it can be difficult to form a nice smooth tip by having many sections that then suddenly collapse down at the end, it's easy to get artifacts especially in the tip region where you've got elognated shapes trying to all collapse down to a single point.

To have a smooth tip you want things generally more shaped like a surface of revolution in that area, and so to make things shaped more like that you want to start to make the end shapes more evenly formed more like a circle instead of elongated. Sometimes just one single circle as the profile at the tip can help, see here for some discussion of this:
http://moi3d.com/forum/index.php?webtag=MOI&msg=4650.4

But also if you want to focus on making a smooth tip, using a revolve or rail revolve for generating the whole shape will make it easier to get a high quality tip.

When doing a revolve, instead of making a bunch of sections you will instead make just one long side profile running the full length:



If you want it elongated in one direction then make an ellipse shape to use as the rail for rail revolve:



Select the profile, then run either revolve or rail revolve if you want to use the oval for a stretched out shape, then for the revolve axis you want to pick a line running down the center like this:



That will make this kind of result:



- Michael

Thanks Michael, Interesting posts. (Especially that 'Keep Tangent' option)

I get what you mean however the fuselage shape in question the profile for the top and bottom are different hence I was forced to look at lofting and sweeping.
However as you mention the tip and tail suffer from small artefacts. (when i do it).

Hi Steve - well if the main body does not have very uniformly shaped profiles, then it does not tend to make a very good shape near the tips when you're trying to collapse things down to a single point. It's too easy for artifacts to be produced by shapes getting bunched up and squished together.

A lot of times if you're getting artifacts and fighting with stuff trying to make one single surface that is going through some significant changes in shape (like in your case near the tip you want something pretty different in shape than in the mid portion of the body), it's a sign that you're trying to do too much all in one single surface and you probably need to build it out of some separate pieces.

It could help though if you start to transform the shapes of the profiles to be more like a circle as they near the tip.

- Michael

right, I'll take that on board

Thanks again

Steve

Did you know............

DId you know that revolves can have the points turned on? The point structure is derived from the revolve curves points. You can do a rail revolve, then pull some points to get it asymmetrical.

(Note: At some value of adjustment, the revolve will "Break" and seperate surfaces out of tangency.)

Hi Burrman,

"You can do a rail revolve, then pull some points to get it asymmetrical."

Sorry you lost me

""""""""""however the fuselage shape in question the profile for the top and bottom are different """"""""""""""""""""

Revolve the top shape, then turn on points for the revolve and pull out the bottom shape. (Again, moving a revolves points to far will break the revolve.)

ummm I'm having another senior moment :)

If I'm following you correctly I have revolved the my profile with the Ellipse rail curve. (Rail revolve)

However if I then show points on the profile and move the points the changes are reflected on both top and bottom as expected.
If I show points on the rail and say change position of a point on the rail then the change is reflected along the shape.

???

With a revolve, you can show points on "The solid"....

Hi Steve, yeah Burr means select the output surface and then turn on the surface control points, not turn on control points for the input curves.

If you want to experiement with that method for deforming the surface, you'll need to either delete the end caps of the revolve or turn off the "Cap ends" option when creating it so that you've got just one surface instead of something with multiple surfaces joined together, and then you'll be able to turn on its surface control points.

Also if you want to try that method, it may work better if you create a regular symmetrical revolve to start with instead of a rail revolve - a regular symmetrical revolve will get converted to a fully squishy surface by a kind of internal surface rebuild if you start pulling some of its control points around.

- Michael

Wow I didn't know that, thanks guys

I have a play around tomorrow

Is this unique only to revolve?


Steve

Hi Steve,

> Is this unique only to revolve?

Well, you can turn on surface control points for any surface object - but not if you've got an object made up of multiple trimmed surfaces that are joined together. When you've got an object like that it will not show control points because it would be too easy to pull them apart and make their joined edge not touching anymore. There's some information on this in the FAQ here:
http://moi3d.com/faq#Q:_Why_does_show_points_work_for_some_objects_but_not_others.3F

But if you get any surface down so that it's just 1 single surface all by itself (either delete other pieces, or use Edit > Separate) and not joined to anything else, then you can turn on surface control points for any individual surface like that.

- Michael