"Anthony D. Baye" <Sha### [at] spamnomorehotmailcom> wrote in message
news:web.4a392bafc3d6106c231d6f4b0@news.povray.org...
> I'm currently working on a project that will require a number of
> strategically placed trees and other plants. The problem I'm
> having is that, though there are a number of macros and utilities
> to create organics for import into POV, some with very good
> results; the mesh objects, once imported, tend to interfere in
> ghastly ways with my scene geometry.

By 'interfere' I take it that you mean that the plants grow through other 
objects in your scene. One very simple approach to resolve this is to use a 
CSG 'difference' operation with the generated vegetation to slice away 
offending foliage. The best results can be achieved by defining shapes 
specifically to 'trim' the generated objects, rather than using scene 
objects themselves. The prism object can be handy for this sort of thing, 
for example, creating a clearing or a path through a forest.

You also need to make sure you don't root a tree or a plant too close to the 
cleared area, otherwise you can end up with unsupported branches. This can 
usually be readily accomplished within the macro or algorithm you use to 
position the objects on the surface.

> Might it be possible, in some future version of POV to have parametrized
> plant-life objects in the SDL itself?

As you've noted, there are already macros that generate parameterized 
plant-like objects in the SDL itself (so no import required). Clipka 
mentioned the Ivy macros, there is also TomTree by Tom Aust which generates 
quite an impressive range of trees and shrubs directly using a wide range of 
variable settings. There's even a Java utility application (POV-Tree by Gena 
Obukhov) to generate the parameters required, or to generate mesh-based 
trees as POV-Ray include files.

The range of potential organic forms needed to emulate plants in detail 
would be huge and it doesn't seem quite right to me that POV-Ray itself 
would incorporate specific detailed real-world objects.  On the other hand, 
the POV-Ray Object Collection is intended to contain specific objects and 
generic macros written using POV-Ray SDL and distributed under a common 
license that would enable them to be shipped alongside POV-Ray in the 
future.

> I would very much like to place a tree at a given location and have it 
> grow
> at that spot without passing through local objects.

This final point could touch on collision detection, which POV-Ray doesn't 
really do, although you can achieve some crude forms of collision detection 
using the built-in 'trace' function that enables you to 'grow' things round 
an object rather than passing straight through them.

Regards,
Chris B.

Post a reply to this message