On Thu, 14 Feb 2002 15:18:11 +0100, Christoph Hormann <chr### [at] gmxde>
wrote:
> object pattern & isosurface are not a very
> good combination.

Well, I have an idea around this problem. In the truth it's even feature
request. What about changing definition of Inside method of objects ?
I mean if it could return not only yes/no to describe object but variable
float value to describe distance (not in units) to surface just like
isosurface does. So positive value means outside, zero means surface, negative
means inside.

In particular:
- for plane it returns linear distance to plane
- for sphere it returns distance to center minus radius
- for cylinders, cones, linear lathes, linear prisms, boxes, disc, separated
triangles, polygons, heighfields, torus etc. it returns obvious combination of
plane and sphere method listed above
- for csg it returns min/max of insides of components (just like method used
in isosurfaces)
- for isosurface and blob it returns value of function modified with threshold
- meshes and other patches has no inside now so no problem with them

I suppose it could be probably possible also for rest of object like: julia,
curved lathe, prism, sor, and sphere_sweep, superellipsoid, ttf, quadrics,
polys etc. They are available with formulas so probably calculation of value
could be possible.

I want to highlight that I don't mean linear distance. I mean value of math
formula used to build shape.

It should allow then recreation of object via object pattern with isosurface
and easy displace of surface of complex CSGs, bending, twisting perhaps even
beveling etc. It could be probably either blur  and proximity pattern :-)

What do you think?

ABX

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