[osg-users] Geometry of Generic 3D Surface from Collection of Points

[Erik Hensens]

Thanks Sebastian,

My requirement is not actually as simple as trying to graph a 3D function, I was just trying to keep my question clear. In reality I just have the coordinates of the boundary of a three-dimensional path that I need to represent with a Geometry. It looks like the CGAL library is capable of performing 3D tessellation, so maybe that's the way to go.


SMesserschmidt wrote:
> Hi Erik,
> 
> From what I understand you have a function generating a z value for x,y 
> pairs. So basically you simply have to sample your function in regular 
> distances to get the triangle coordinates.
> If you already have the sampled points without further information you 
> need to use the delaunay triangulation. IIRC, If it is a function the 
> folding should not be problem for the delaunay algorithm, so I don't 
> know if Roberts comment might be misleading.
> 
> Cheers
> Sebastian
> 
> > Thanks for the response Robert!
> > 
> > So, does that mean that there is no way to do what I want without somehow determining the coordinates of every individual triangle? And there's not even any way to do a 3D tessellation to get such triangle coordinates? :'
> > 
> > 
> > robertosfield wrote:
> > 
> > > Hi Erik,
> > > 
> > > 
> > > The OSG has the osgUtil::DelaunayTriangulator and the GLU based osgUtil::Tessellator can be used for tessellating meshes, but both utilize a 2D projection to a plan to work out the connectivity so aren't appropriate for meshes that will be folded.
> > > 
> > > 
> > > 
> > > Robert.
> > > 
> > > 
> > > On 17 August 2015 at 02:21, Erik Hensens < ()> wrote:
> > > 
> > > 
> > > > Hi everyone!
> > > > 
> > > > I have a collection of Vec3 vertices that define the shape of a geometry that I'd like to create. Typically I would create the geometry by adding a primitive set of the POLYGON type, but what should I do if the vertices are not all in the same plane?
> > > > 
> > > > I'm sure this is a very common task and that there's probably a simple way to achieve this. What is the best basic approach to creating such a geometry?
> > > > 
> > > > Ideally I'd like to be able to do this without having to choose the individual triangles or quads that will make up the entire geometry. For example, if I wanted to model any generic three-dimensional surface and all I had was a large sample of points on the surface.
> > > > 
> > > > In case I'm not doing a good job explaining what I need, I've attached an image - let's say I had many points on the surface of that shape and I need to make a geometry that depicts it. How would I do this?
> > > > 
> > > > Thanks in advance for your help![/img]
> > > > 
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> > > > Read this topic online here:
> > > > http://forum.openscenegraph.org/viewtopic.php?p=64792#64792 (http://forum.openscenegraph.org/viewtopic.php?p=64792#64792)
> > > > 
> > > > 
> > > > 
> > > > 
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