On 06/09/2016 10:54, John Greenwood wrote:
> This has been a fascinating discussion. The conclusion seems to be that a
> general purpose fillet/round provision is not realistic.
>
> However I wonder if there are limited cases where solutions can be found, for
> example
>
> All CSG objects that contain only spheres and sphere sweeps etc., fillets could
> be defined by blobbing, although I think this could be made more general and
> intuitive.
>
> The intersection of two conic section primitives, will itself be a conic
> section, so that an equation for it could be written for an extra CSG component
> in the form of a sphere sweep following that equation. All under the hood of
> course!

The sphere sweep doesn't follow the intersection curve, that would give 
you a "bead" along the edge. The sphere sweep needs to be offset a 
variable amount to ensure that the contact between the sphere sweep and 
both CSG surfaces is exactly tangent along the whole length. Then the 
CSG is not trivial, you need just the bit of material between the sphere 
sweep object and the two surfaces.

I'm not saying it's impossible, just a lot more complex than it first 
seems. Try writing it as an SDL macro first - if it works well then 
maybe it will get implemented natively...

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