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View Full Version : "Edge Selection Sets" - make any sense?/ FReq: EDGE SETS



jeric_synergy
08-13-2015, 05:02 PM
POINTS get Selection Sets - any point can be in any Set, simultaneously
POLYS get Parts - a poly can only be in ONE Part

Does it make sense to want an analogous entity for Edges? I'd expect so, because some Point selections are ambiguous about the Edges they could describe.

meshpig
08-14-2015, 12:28 AM
Edges, probably not but for polys as a floating button/gizmo type toggle. Parts are methodical, which is fine but a quick poly sel. set would be fun.

probiner
08-14-2015, 02:08 AM
http://forums.newtek.com/showthread.php?131672-Edge-Sets

Sensei
08-14-2015, 04:49 AM
Edge selections are stored by TrueArt's Selection Preset Manager:
https://www.youtube.com/watch?v=j2ZjSKGJxqE

Usage: when we have complicated model, select bunch of edges (points/polygons), then have to work in other area (drop tool/drop selection). And we want to get back to older selection of the same elements.

jeric_synergy
05-24-2018, 09:22 PM
Edge selections are stored by TrueArt's Selection Preset Manager:
https://www.youtube.com/watch?v=j2ZjSKGJxqE
Sensei: would your plugin work in the illustrated situation here?:
141847

In this case, the old "save as Point Selection Set" hack will not work because the points are ambiguous as to what Edges they describe.

Sensei
05-24-2018, 11:43 PM
Sensei: would your plugin work in the illustrated situation here?

Yes. Plugin stores (and then verifies existence while reselecting) LWEdgeID pointers, instead of pairs of LWPntID. Low level hack. It's valid during session.

jeric_synergy
05-24-2018, 11:49 PM
Yes. Plugin stores (and then verifies existence while reselecting) LWEdgeID pointers, instead of pairs of LWPntID. Low level hack. It's valid during session.

Excellent.

Cuz it was a PITA trying to save the Edge Selections on this object.

Sensei
05-25-2018, 01:06 AM
LWEdgeID is valid during session. They're not stored in LWO between sessions. They don't exist in LWO file format (at least original IFF LWO, not sure about LW 2018 extensions).

jeric_synergy
05-25-2018, 12:32 PM
LWEdgeID is valid during session. They're not stored in LWO between sessions. They don't exist in LWO file format (at least original IFF LWO, not sure about LW 2018 extensions).

Ah, thanks for that expansion. --OBTW, are any such entities included in, say, OBJ format? Or something else we can both save and load??

Sensei
05-26-2018, 12:10 AM
OBJ file format has only
v x,y,z[,w] (vertex making command)
f a,b,c[,d] (face (=polygon) making command).
vn (vertex normal making command)
vt (vertex uv)
plus couple pretty meaningless.

Kryslin
05-26-2018, 07:32 AM
Just a thought: LW has the ability to add tags to polygons. It would be clumsy, but couldn't a tag be added that stored the edge information? Say, as an array of point indices? That way, you could reference edges by polygon index, then side index, with start point being the side index, the end point being side index ++ ( (side_index + 1) % polygon_sides, to make sure you don't over run the bounds of your array)...

jeric_synergy
05-26-2018, 09:27 AM
What about FBX, or just to anticipate :eyeroll: , ANY other format? What supports Edges?

jwiede
05-27-2018, 11:04 PM
Just a thought: LW has the ability to add tags to polygons. It would be clumsy, but couldn't a tag be added that stored the edge information? Say, as an array of point indices? That way, you could reference edges by polygon index, then side index, with start point being the side index, the end point being side index ++ ( (side_index + 1) % polygon_sides, to make sure you don't over run the bounds of your array)...

It could kind of work, but there are some serious issues: A poly getting created/deleted/modified then impacts the edge data structures, those edges associated with the poly have to be appropriated handled (and more subtly, those manipulations require quite extensive, perf-costly data alterations across potentially large data sets). Tractable given a certain infrastructure design, but LW doesn't really work in the way you'd want for that.

As is, doing so would require non-trivial modifications to any tool/command which can delete/create/split polygons in order to add the needed edge mgmt. bookkeeping. Unfortunately, that isn't likely to happen other than if they're bulk-rewritten during adding tools to Layout or unification or whatever. In that case, too, might as well just add proper edge mgmt from scratch -- if infrastructure is being rewritten anyways, better to do it in a proper, maintainable manner.

Kryslin
05-28-2018, 07:25 AM
Yeah, after thinking about it, It's a kludge, and way too cumbersome to shoehorn that in.

Even using a custom data block to just store the selection gets cumbersome, when you start slicing and dicing polygons, using a 3rd party plugin.

So, I agree : edges have to be handled at a low level, so as to be tranparent to every tool without having to rewrite every tool to handle adding, changing, splitting, modifying, etc and updating the selection sets, too.