On 12/20/2015 02:33 AM, Sven Littkowski wrote:
> Hi,
>
> I have a (red) cylinder, and want to add - with smooth transitions - a
> number of (purple) cylinders at its end. But my understanding of the
> blob object is not very good, and so i simply don't succeed.
>
> --------------------------------------
>
> Can you give me advises, how to create a smoother transition between the
> purple and red cylinders? Thanks a lot.
>

Blobs are difficult to control precisely especially given we have only 
spheres and cylinders with which to work. Where precision shapes are 
desired, folks tend not to use them.

Given your magenta cylinders are placed so near the edge of the red one 
you wished to be a fixed radius, the red is going to bulge outward.

That said, some suggestions :

Blob only :
-------------------------
1) Move the magenta shape away from the red cylinder edge if able.
2) Use many more smaller radius magenta cylinders to reduce the bulge / 
lesson the inset distance for no bulge.
3) Perhaps you could come up with an negative strength tube made up of a 
larger negative strength cylinder mostly already neutralized by inner 
positive one(s). Complicated to get clean.
4) Surround the bulging parts with many carefully positioned negative 
strength shapes, but again the red shape wouldn't be completely 
cylindrical, though you could get quite close. The neg strength shape 
count would likely be high meaning possible impacts to parse and render 
performance.
5) I've seen mention of POV-Ray blob modeling tools, but not something 
I've used.

Shape aided / shape based
-----------------------------
6) Intersect the blob you have with a cylinder of the radius you want. 
In other words constrain the blob bulge with CSG.
7) Drop the blob approach altogether and use CSG - see, for example, the 
rounded shapes package(s) in the objects collection. With pure CSG you 
of course then need somewhat more complicated textures but looks like 
you could use a gradient pattern as a basis.
8) Meshes & UV mapping probably using a modeling tool like Blender...

(6) Is probably the quickest fix.

Bill P.

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