POV-Ray : Newsgroups : povray.binaries.images : Veined marble objects using SSLT (new in Beta 32) : Re: Veined marble objects using SSLT (new in Beta 32) Server Time
31 Jul 2024 20:15:25 EDT (-0400)
  Re: Veined marble objects using SSLT (new in Beta 32)  
From: MessyBlob
Date: 19 Nov 2010 20:00:01
Message: <web.4ce71d4a4695c623addfbead0@news.povray.org>
"clipka" <nomail@nomail> wrote:
> Unfortunately(?), the model on which the SSLT algorithm is based is not really
> "volume aware": Basically all it does to compute the apparent color of a point
> on the object's surface is sample the incident light at some other surface
> points nearby, and then apply some smart math to it.

I was wondering how easy it would be to have the SSLT algorithm cope with
transitions from one SSLT object to another. This comes from the limitation that
currently, any SSLT objects must be a single object (implicit function, blob,
etc), and any CSG (or just one object seemlessly abutting another) causes the
SSLT algorithm to register shadow for the surface that is hidden.

I guess any transfer between surfaces would be recursive in nature (for each
transition point between materials), but could be optimized to be nearer linear
complexity using some caching. How would one get around volume intersection
problems, where it would be difficult to decide whether two objects are abutted,
overlapping, or disjoint? (I think I've had a similar discussion in the past
about a different feature - where I suggested a distance threshold: in this
case, for shorter distances, the SSLT transfer is interpolated between 'abutted'
and 'disjoint' values).

p.s. I've been away from POV-Ray for about 18 months (life!) - good to see
recent speed and smoothness/sampling improvements for SSLT!


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