Selecting edgeloops in Maya

fogmann

Does anyone know if it is possible with some script or plugin (or simple trick?) to select edgeloops in Maya 8.5 on triangulated meshes? So far I had no luck with NEX, OMToolbox and maya's native edgeloop selection tool.
Thanks!

MoP

Hmm, that's a bit of a tricky one, since you don't necessarily know where an edge loop is running ... you'd have to either take educated guesses based on the angle of the edges connected together relative to the surface, or some kind of brute-force check against all connected edges until you hit a set of edges which form a closed loop with the original one.

Well, those are my initial thoughts anyway, I'm not much of a programmer but that's probably where I'd start. It seems like it'd be pretty tough to make a reliable script to do this though, since a triangulated mesh means edges could lead anywhere really.

This is one of the things that Maya is actually pretty bad for, since you can't natively edit triangulation of a quadrangulated mesh (which would usually mean you could avoid this situation in the first place). Plus because of this, you won't have much luck using a Quadrangulate method since you'll end up losing all your bisecting edge directions from the quads.

If you don't care too much about keeping the triangulation identical, I'd say giving Quadrangulate a go is your best bet.

fogmann

Thanks, MoP! The thing is, the edge loops we need to be able to select are mainly straight as we're dealing with vehicles, so it might not be that hard to write a script that does just that kind of edgeloop selection, e.g. continuous edges that connect at certain angle, but I'm not much of a programmer either. Well, it's supposed to work in XSI, sigh... Unfortunately, we can't go back to quads, even if Maya decides not to mess things up too much with its quadrangulate function, since vert order needs to be preserved so that the blendshapes would work.

Anyhow, I found a script on highend that might do the job... it's Select shortest edge-path and if the surface doesn't curve much, chances are it will do the trick.

ivars

Have a look at "select continuous edges". It's the old version of edge-loop select but it operates on an angle threshold so it should work on your triangle mesh as well.

claydough

ivars wrote: »

Have a look at "select continuous edges". It's the old version of edge-loop select but it operates on an angle threshold so it should work on your triangle mesh as well.

select > select "Contiguous" edges

or run

SelectContiguousEdges;

claydough

It's a poly select constraint

depending on what yer geometry is doing
try:
select > select using constraints
for more options than the select contiguous edge angle options

fogmann

Yep, that works pretty well, thanks!

Toast

MoP wrote: »

This is one of the things that Maya is actually pretty bad for, since you can't natively edit triangulation of a quadrangulated mesh (which would usually mean you could avoid this situation in the first place).

It's not necessarily a "bad thing" because, again, Maya works differently to Max.

Max uses tri based polys whereas Maya uses real polys. So the reason you can't edit the tris on a poly mesh in Maya, is because a quad is just that...a quad.

The "Hidden Edges" feature is just to show what the mesh would look like if triangulated and does not indicate the tris on a quad mesh because that doesn't exist.

OP: You've probably already found it by now but the Select Shortest Edge Path tool works quite nicely because you can manually "steer" the select path.

funshark

Toast wrote: »

Max uses tri based polys whereas Maya uses real polys. So the reason you can't edit the tris on a poly mesh in Maya, is because a quad is just that...a quad.

The "Hidden Edges" feature is just to show what the mesh would look like if triangulated and does not indicate the tris on a quad mesh because that doesn't exist.

I don't really understand that point.
If the tris don't exist, so why the quad isn't a plane? ( i mean a perfect plane )

MoP

Toast: Yes, but for game development that's a pretty poor workflow. A lot of the time you will want to keep edge loops and quads for ease of selection, and at the same time control the triangle direction to improve surface shape and prevent nasty collapsing during deformation (particularly around shoulder/hip areas).
Currently the only way to do this in Maya is to Triangulate the areas you need control over, which naturally breaks the edge loop selection tools.
In Max you just go into Turn Edge mode, it displays all hidden edges as triangles and you can turn them at will.

Max uses tri based polys whereas Maya uses real polys. So the reason you can't edit the tris on a poly mesh in Maya, is because a quad is just that...a quad.

This makes no sense. Everything is triangles. Do you even know what you mean when you say "real polys" ? Because I don't. A polygon is a collection of triangles, that's the only thing a consumer video card knows. You can see this at any time in Maya by just turning on Show Triangulation. There is zero difference to Max here other than Max lets you see and edit the triangulation.

It's the difference between a choice of workflow, and no choice at all. In this respect Maya is inflexible unless you want to spend time writing your own triangulation control plugin.

Toast

I know how it works in Max, but I was just pointing out that that "edge" data does not exist in Maya at all - "hidden edge" data is just to show what the mesh would look like if it were triangulated. Max and Maya handle polys differently.

Yes, outside of Maya things like gfx cards and renderers depend on tris, but AFAIK Maya internal render and other renderers like renderman do not triangulate. Polygons are not always tris in computer graphics.

Of course this now way off topic and I agree it would be nice to edit these hidden edges but it's not completely necessary. More things need improving in Maya than that.