Hi Micha,

> WOW, I increase the angle just for fun and the mesher dosn't
> create crap (case (8) - the Rhino "o" with rounds), it looks like
> it should look, also at this extrem raw angle. I'm impressed!

:) It depends a bit on the particular situation though, if you end up with a surface that has only one polygon for the surface part, but an edge gets a refinement in the middle of it, that refined point of the edge will be placed at the actual point on the curved edge's midpoint which is then a far distance away from the single polygon that is approximating the surface. That then makes for a kind of very warped polygon.

It basically causes a single polygon to have a very non-planar shape, which makes for somewhat odd looking polygons.


> ... but I found, that the result is not stable at all angle values -
> maybe it's possible that the mesher can be refined to avoid
> this effect

I guess it would be possible, but it would probably need a special "low polygon" mode that tried to do things in a special way that did not follow the regular method used for normal meshing. Unfortunately that would probably take a fair amount of work so it is not too likely that I will be able to accomplish that anytime too soon. I'd also worry about cluttering up the UI with specialized tools that were only useful to a very special kind of case, that is not so good because it means that the main tools become more complicated to use for everyone and the only benefit is to a very small area of work. That's how adding some things can actually end up with an overall negative effect rather than being an overall benefit to a larger group of users.


Some more notes on the strange-looking result:

Under normal circumstances it is important to be able to have an edge refined with points added to it to an additional amount beyond the surface that it is on, because an edge can easily be curved in shape a lot more than the surface.

Here is a basic example - here I have a plane so the surface is not curved at all, but meanwhile the trim edges of the surface have a very curved shape:




If I did not refine edges to have additional points, then a shape like this would end up with a mesh looking like this:



Which as you can see would not be a good result for the most regular meshing cases such as regular rendering, etc...


Basically for extremely low polygon shapes like you're experimenting with here, I would recommend building those using the tools in a polygon modeler like jonah mentioned, that is a toolset that is specifically designed for that purpose.

The case you are showing here is starting with a very curved shape, that's just not really the best starting point in general if you want an extremely angular result, it is better to use a toolset that is specifically designed for that kind of a thing to get the best results.

- Michael