View Full Version : modelling drop-like bodys

08 August 2009, 10:56 PM
I am searching for a function, which propably in blender doesn't exist. I hope there is a workaround or a part-solution for what I search. Here is the problem:

To model a natural looking waterdrop-like body (often used for car- or airplane-design, in nature found at insects-bodys and fishes), I search a function which extrudes and scales a shape along a path (curve). I wanna use two or three shapes/curves to let Blender interpolate a 3D-Object out of it.

Maybe usually modelling a spline-cage would help achieving drop-like objects. But since it is very difficult making it perfectly round, and since it is impossible to easyly change the shape, a spline-cage is not good enough. In other words:
I search something like auto-creating 3D-Objects out of Splines or shapes.

An ideal solution would be something like a ball where you can manipulate the Spline-Curves (especially at their crosspoints) in each axis.

-I tried it with nurbs, but I am not satisfied, since it is too difficult closing the surface without mistakes.

-Tapering an extruded shape along a curve, creates two ends, which you have to close manually (basically same problem as with nurbs).

-The spin & spin-dump-functions look useful achieving my goal. but I don't know how to use them properly. I also thought about Rotating / and or Scaling in an stairs, but maybe in edit-mode and not shifted.

Hope you got what I mean. If you have ideas, please post them.

08 August 2009, 12:28 AM
Have you tried adding a uv sphere and placing it in a lattice modifier to get the shape you want. Here's half a uv sphere, just scaled on the x and z axis and placed in a subsurf modifier.

08 August 2009, 08:56 AM
I think he is looking for lofting as it is called in other applications (with ability to specify the intermediate perfil shapes).

I you only want to use a shape:
Create a bezier curve, that is the path to follow.
Create a bezier curve and give it a shape, that will be the perfil.
Create a bezier curve and give it a shape, that will be the size of the perfil along the path.

In the path curve go to editing panel (F9) and you can see two boxes to enter the bevel object (perfil curve) and the taper curve (our third curve).

I think there is no possibility to create more perfiles than one per curve. Am I right?

If you need to use several shapes:
In this case you can edit each shape.

But of course I think I will model also as the previous post such an object probably.

08 August 2009, 08:32 PM
The lattice-modifier gives a perfect solution. Thank you for that.
However the way is completely different. The number of polygons is increasing too fast.

You get good drops, but I search something more precise for constructions. An airplane-body for instance, has a linear roof, a round nose and a sharp tail. Nosa and tail are not axis-symmetric. You can't model that with Baos method (I tried, the problem is the nose, for which you need an additional curve).

The skinning tutorial was the first I tried. I approximately got what I wanted, after a lot manual work (like with spline-cage). But what I search is something on a calculated basis, so that the surface tension is based on a mathematical curve. I don't wanna modelate the surface.

I wanna construct it with shapes, functions or mathematical curves.
So what is Loft?
Are there other ideas?

08 August 2009, 09:40 PM
Lofting is just basically skinning a bunch of curves, check out this link

08 August 2009, 05:31 AM
So Loft is a nurbs-function?! Interesting. The boat-tutorial has the problem of the two linear ends. What I wanna do is: let blender create the stepwise smaller scaled shapes, using a curve. This way nose and tail schall become round.

Forgive me my peristence. There must be a way. This option is so obviously missing. I try discribing it in a different way:

When using Baos method, which I tried a couple of times, you

1st) extrude a shape along a path (bevel)
2nd) use a curve to adjusting the width (taper)

A third function is just missing: Adjusting the falloff of the tapering (using an additional path).
You always get something like a stick or a tape in result.

Start and end of the extrusion shall be round. The extrusions start- and endpoint shall not be flat, not sharp, it shall be regulated with a curve.

Extrusion is internally working with copying and moving a shape X-times. The movement can follow a path.

I want an extrusion which is copying and SCALING X-times along a path. And of course the scaling shall be regulated with a path as well.

So, who has ideas? Are there other functions which can be used for this? Are there scripts for things like this? Is there a workaround with the curve-editor?

The task is actually simple: I wanna path/curve-regulate an object a third time, to curve-regulate in 3 dimensions, not only 2.

08 August 2009, 04:22 PM
I don't know if this video tut I did is what you've already tried, but this is what Bao is suggesting. (no audio) (right click save as ~48mb)

If you make the original curve that is being affected into a 3D path (click the 3D button in the panel), then you get another dimension.

You could also team this together with a lattice modifier for more control.
vimeo version (lower quality): (watch full screen).
youtube version (low/HD version): (full screen again)

08 August 2009, 04:33 PM
it's not quite Max's loft, or the boat skinning technique, where you can control different shapes in between, but it's still pretty good, IMO.

08 August 2009, 06:49 AM
And you used the 3D-Button of a Bezier-Curve?

...scaling with Y-Axis-movement...
...width/height adjustement with shape-deforming...
...length is defined by Curves X-Axis-Length

Yes, I think that is what I looked for. I will try it immediately, next time I continue my modelling.

08 August 2009, 04:02 PM
in the video I didn't use 3D Path... just played with it after it was uploaded.

08 August 2009, 10:38 AM
The number of vertices of the curve is important because there the deformations are created.

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