Hi Michael et al,

Playing around with MoI I got an idea for a function I'd love to see implemented if it's possible.

Here's an image of a random curve, and an extruded and filleted copy of it, to slightly approach my idea.



I hope I can explain it clearly:

A function that takes a curve (closed, or otherwise auto-connecting loose ends) and blows it up to a 3D solid with perfect roundings, where the extent of the rounded volume is determined by the surface areas in the curve. So the larger the area in the curve, the larger the round volume of that area in the 3D result.

My example doesn't show more rounded volume in larger areas, because I used only extrusion and filleting, but I hope you get what I mean: a perfectly rounded, organic 3D volume derived from the boundaries and area sizes of a curve.

• Edit — found a video of a 3D tool that creates such a 3D volume from a single 2D curve (skip to 0:30 seconds):

http://www.youtube.com/watch?v=W0XGkS7zebo

hum :)
Seems your form is the best that you can obtain with this curve!

Hahahah! :) After creating the curve and posting the screenshot I also had a certain visual association, assuming that's what you mean (otherwise it's only my dirty mind). :D

> where the extent of the rounded volume is determined by the surface areas in the curve. So the larger the area in the curve, the larger the round volume of that area in the 3D result.

I did not get this part. Are you trying to generate something like this???

1. create a curve, closed or open.
2. create an arc, half circle to be exact.
3. do "sweep" between them; curve as the rail, arc as the profile
4. do "planar" to cap bottom and top openings if your curve is a closed curve.

so you're asking a script which will do things above while determining the highest radius of the arc where sweeped curve will not entwine?

this is what I was talking about:

This video shows the generation of the rounded 3D volume I mean from a 2D curve:

http://www.youtube.com/watch?v=W0XGkS7zebo

yes at 0.38 :)
But very more easy than your curve because follow diameter is quasi constant!



Maybe also something like that with offset level of the first curves
And rest to calculate a boolean "skin" :)

You mean like the Z-Spheres of ZBrush. :)

http://www.youtube.com/watch?v=rR3b1JfE0qc

Hi Metin,

> This video shows the generation of the rounded 3D volume I mean from a 2D curve:

Unfortunately it's difficult to make this same kind of process happen with NURBS surfaces instead of polygons.

Polygons have the benefit of "arbitrary topology", you can stick a bunch of little ones together any way you want.

NURBS surfaces are not like that, a NURBS surface is made up of a regular grid of control points, with a specific row and column structure to it. You can't just add in a single point all by itself somewhere in the middle of a surface to make a protrusion, it has to be an entire row or column of points added in at one time.

The kind of technique that is used to make those puffy shapes in the video you linked to, really relies a lot on that "arbitrary topology" type structure, so it's hard to do the same thing with a NURBS surface.

- Michael

And although it's not the same thing you're talking about, if you want a kind of rounded top face to just avoid some overall flat look, you can model a curved cutting surface and use it to slice off the top of an extrusion instead of having a flat top. Check out these examples:

http://moi3d.com/forum/index.php?webtag=MOI&msg=606.4
http://moi3d.com/forum/index.php?webtag=MOI&msg=3137.5
http://moi3d.com/forum/index.php?webtag=MOI&msg=2909.2
http://moi3d.com/forum/index.php?webtag=MOI&msg=2666.5
http://moi3d.com/forum/index.php?webtag=MOI&msg=1782.4
http://moi3d.com/forum/index.php?webtag=MOI&msg=4296.5

- Michael

Many thanks for the info and links, Michael. I'll check them out.