Hi Micha,
quote:
(4) mesh #2
This object is a "o" from a Text object "Rhino". Interesting for me is, that you talk about independent edges and surfaces. I thought a surface or polysurface has edges, but you extract and delete them. That's I don't understand.
"I've attached an updated version of your object here as mesh#2_quads.3dm - to simplify the edges of this shape, I took your object, used Edit/Separate to break it into individual surfaces, then selected all the edges of those surfaces and did a Delete to "untrim" them and get the natural surface isoparms as a new simple trimming boundary, and then rejoined."
You wrote:
> I thought a surface or polysurface has edges
Yes - every surface or polysurface has edges to it - but part of the definition of an edge is a 3D curve that gives the shape of the edge (there is also a UV curve that is in the UV space of the surface). In this case that 3D edge curve is pretty complex, just take a look at the screenshot which I will show here again:
That edge has gone through some kind of "fitting process" to calculate it as an approximation, maybe as an intersection between 2 surfaces or something like that.
Anyway, as you can see from the number of points in it, the 3D edge curve is not as simple and clean as it could possibly be, to get a better mesh I removed the existing 3D edge curve (by "untrimming") which forced a new one to be calculated from the underlying surface. The new 3D edge curve is more simple in structure and exactly matches the underlying surface, making it a more simple structure overall and helping to build a better quality mesh.
> Could it be possible, that this is internal automatic done for meshing?
Unfortunately it is kind of tough, often times you need a kind of human intelligence to analyze the shape and see what parts can be simplified. It can be difficult to replicate this with a kind of artifical intelligence.
It's also possible that in different situations this kind of process can change the shape of the object slightly. I kind of worry a bit about doing things automatically that change the shape, it is another area that can require judgement.
> Or can I do something at Rhino befor export an object to MOI?
Possibly either "untrim", or "RebuildEdges" in Rhino could be used for a similar process.
> Are the edges needed for meshing?
Edges are definitely used in meshing, without processing edges then you would only ever have meshes that used the "underlying surface" parts of objects and not any trimmed areas which are often formed by booleans, etc...
Edges that are messy or more complex than needed, or wiggly, etc... can introduce complexity into the generated mesh, same as if the surfaces are more complex than needed or wiggly, ...
> Is at MOI at command to select all edges?
You just first select one edge with the "drill-down" click (when you click a second time on an object), then use Ctrl+A to select all.
- Michael
