3 replies to this topic

[patrick.lindall]

Hello all.

I really hope someone can help me for rhino.
I am creating a helmet or dished styled shape from three curves.
1.The outer perimeter is a rhino ellipse (labelled base ellipse in images)
and I want the helmet form created from two different shaped sections going along the
2.major axis ( section 2 in images)
3.minor axis of the ellipse. (section 1 in images)
With clean geometrical transitions in between.
I originally modelled using patch command, which gave fairly please results, but the surface was never tangent to the base ellipse.
I then rail revolved the minor axis along the base curve, to get one section nice, switched views and turned on control points on either side of the surface to eye up the section for the major axis. This worked pretty well but left me with a crease in the surface when I went to analyse it. I then chopped the crease out either side and blended the surfaces together, pretty pleasing result but again i loost the tangency of the base ellipse right on the side ob the blend.

I am sure the is something i am missing. I have also tried dividing into quarters and network surfacing, but that leaves me with more creases and an uneven surface.

Any suggestions would be amazing.

Patrick


Here are the direct links to the images

http://img153.images...56/unled3es.jpg

http://img844.images...67/helmet2j.jpg

Attached Files

•  Untitled-3.jpg   84.73K   1 downloads
•  helmet2.jpg   149.48K   3 downloads

[waikit]

Have you checked available online rhino tutorials to help yourself out?

I would split this model up into 2 mirrored parts divided by the section 2 profile, and then build that half part with more sections and using sweep 2 rails.

[patrick.lindall]

Thanks Waikit.

I consider myself pretty decent at rhino, I will try it with maybe two more sections like you say. My idea was to give as little info as possible, I remember in Pro e I believe there was a command called variable blend or blend sweep and it worked perfectly for this kind of form.

I have always found that with nurb modelling in rhino, you can often get nasty creases on rounded forms where you draw half then mirror. Somehting to do with when your curves come to a point. I know there are various commands to eliminate creases, like merge surface, match surface or remove knot for example, but they often alter other geometry like the "base ellipse" in my image.

Again, Thanks for the advice. I will let you know how it went.

Best

Patrick

[Mr.Black]

patrick, i have used Rhino.. i don't have the software now !
pretty much anything is possible in rhino ! Approach is do the one side and mirror the other ! or you can do quarter and mirror that 2 times !