creation figure - very newbie

[PixXelite]

Bye to all,
I am at the very first weapons with this soft and I already come across what I can't do.
I hope to explain myself well. I wanted to create a form that had as a plant (base shape) a helix but instead of extruding it linearly I just wanted to give it the "bombing" effect. I tried to create an helix (top view), create a surface from this helix, reconstruct the surface (to have the possibility to activate the control points and to deform the surface) but to the reconstruction the surface that was previously confined to the helix becomes rectangular losing its base-shaped.
practically in the outer edge of the figure the extrusion height must be 0 to increase more you approach the center of the figure (exactly as a half helixide or half ball.
and to create the same "bombed" effect on a free-form surface (e.g. stylized leaf shape)?
How can I do that?
Thank you in advance

 

[Fulvio Romano]

Let's start badly.. .
- you didn't show up in the forum
- you didn't even look at some banal tutorials on youtube, even because in the question you answer yourself and don't notice.

I don't know if I understand, but do I think you want to make an elliptical "bolla"? Why don't you use a half ball?

make a ball, cut in half, stop in one direction until you get an ellipse. done. or you can only scale the control points at the base, so you have the elliptical base and the "bolla" that comes back spherical.

for the second point, make a square of the curvature you want, project us over the shape (e.g. of the leaf) and make a trim.

 

[PixXelite]

Sorry, you're right. . .

is that I already posted some times using another account (a friend of mine) [Autocad].
cmq, correcting my huge mistake
All of you!

I have not understood what it means to make the square, and how to project for example the leaf on a convex surface or cancave so that it takes the shape of the surface itself.

tutorials I have seen several but many times I can't find the right keywords... what do you suggest as a keyword?

I have another problem I have seen that if they revolute a helix (creating an helixoid) and I make it cross from a surface exactly in the center (extruding line) they fail to me the Boolean operations (union, difference, etc...) while if the surface moves it even a little over or under the center of the helixoid fus everything.
How come? consider that the surface drained from the helixoid (to avoid there were tangence zones between edges)

Thank you for your readiness and apology

 

[Fulvio Romano]

Sorry, you're right. . .

is that I already posted some times using another account (a friend of mine) [Autocad].
cmq, correcting my huge mistake
All of you!

there is a special area for presentations, not for greetings :tongue:

I have not understood what it means to make the square, and how to project for example the leaf on a convex surface or cancave so that it takes the shape of the surface itself.

Sorry, "square" is a command of another program. I don't use rhino, but I use an equivalent, so I can explain the techniques but don't ask me the names of the commands. However, I meant a surface with four edges.

I have another problem I have seen that if they revolute a helix (creating an helixoid) and I make it cross from a surface exactly in the center (extruding line) they fail to me the Boolean operations (union, difference, etc...) while if the surface moves it even a little over or under the center of the helixoid fus everything.
How come? consider that the surface drained from the helixoid (to avoid there were tangence zones between edges)

Thank you for your readiness and apology

I said to do a ball, not a revolution of an ellipse. Anyway, it's the same thing.
when you make a revolution surface, all isoparametrics (building lines along the surfaces) converge at one point. that point is rather delicate to treat mathematically.
Boolean operations are done on solids, not on surfaces. here they are defined, but they are rather delicate.
put together the two previous points, and you understand why a delicate Boolean operation forced to deal with multiple points...it's so long that it doesn't crash the program.

use the "trim" command. you have to make curves (or surfaces) of cutting, projecting them (or interseal) and thus creating curves on the surface. now do "trim" by selecting the curve and the surface.

 

[AC Design]

Why don't you put what you did? It's not that you're very clear. . .