Alain <aze### [at] qwertyorg> wrote:

> > Warp<war### [at] tagpovrayorg>  wrote:
> >> freddy<fre### [at] yahoocom>  wrote:
> >>> I have a surface object which I can describe with mesh2. I want to make this a
> >>> solid object at least I want the mes2 surface to project as a solid surface to
> >>> -infinity
> >>
> >>    You mean it's an open surface, but you want one of the sides to be
> >> considered "inside" in CSG operations (in the same way as eg. heightfields)?
> >>
> >>    Meshes are made into solids using the inside_vector directive, and it
> >> should work in this case as well. You just have to be careful with its
> >> orientation: You have to orient it so that it points towards the non-inside
> >> part of the mesh.
> >>
> >>    (Eg. if your mesh is an open surface on the xz plane and you want everything
> >> below it to be considered "inside", then a "inside_vector y" should do it.)
> >>
> >> --
> >>                                                            - Warp
> >
> > Thanks very much warp.
> >
> > Sorry for not getting back sooner - I have been busy with other things and ot
> > had much time to play with this (apologies).
> >
> > For the time being I am going to construct a surface by using the intersection
> > of a plane and a prism. It seems to be doing the quite well for a first pass.
> >
> > I appreciate that this method is limited somewhat in terms of using normals etc.
> > in order to refine the final rendered quality but for my current development
> > phase it is allowing me to make progress quickly and I can loop back later and
> > refine the method to do this.
> >
> > Incidentally can a mesh2 and a prism be intersected in the same way to provide a
> > solid surface (ala heightfield)?
> >
> > Cheers
> >
> >
> >
> >
>
> You can use a mesh/mesh2 in an intersection or difference, but it needs
> to be given an interior_vector. With that vector, the mesh, even an open
> one, can be used as a regular object in CSG operations.
>
> Be wary that an open mesh can give you some strange or unexpected results.
>
> If the result shows artefacts, you can slightly change the orientation
> of the inside_vector. This can appen when the inside_vector is parallel
> to a triangle of the mesh and changint it's direction can resolve the
> problem.
>
>
> Alain


Hi Alain,


I tried a very simple triangle surface described by a mesh2 and then rendereded
this with the intersection of a prism and the results were quite horrible - lots
of white speckle

any ideas?

I tried

<0,0.5,0>,<1,0.5,0>,<1,0.5,1>

as the mesh2 and

<0,0>,<1,0>,<1,1>,<0,0> add the prism

this renders horribly much worse that the intersection than a plane and a prism

any idead?

cheers

Post a reply to this message