[Plugin] Face Flattener 0.19

Gaieus

Bob, Zach,

I have a script that creates a menu item "Remove unused edges" in the Edit menu (for the life I cannot locate the script anywhere to see the file name of it). Using the script it also deletes the top surface (so the order it deletes the lines must be wrong as well).

I have noticed a couple of times that using it leads me to lose a coupleof faces (especially after complex, curved intersections).

watkins

Dear Gaieus,

It is cleanup_model.rb.

Regards,
Bob

Gaieus

Ah, thanks a bunch, Bob! I have always wondered and couldn't figure out (I keep a fairly nice mess in my Plugins folder).

RayOchoa

You know what i don in order to get a 2d model is get the scale tool and type in .002 and then do that again by putting a line next to it and resizing again. then i just erase the lines i want after intersecting everything

rv1974

Perfect solution: export-import 2D hidd.line mode dwg.
Not sure it canbe implemented in .rb though

Fletch

RE: Face flattener - I'll give it a shot... thanks for sharing!

Ray, and others, when wanting to export a flat model from SU to CAD format - don't forget the Automated 2D Output ruby! Then you can just re-import the .dwg file back into SU, and it will be flat.

zhuangsuph

wzfwzfwzf

hehe,hello.

fredo6

@cerevellum said:

Hi Ray and Bob,

This is something I've noticed while working on my flattening script, and I still haven't figured out why it happens. The simplest way of reproducing this is to draw a box, add a rectangle to the top surface and connect it with a line to the outer edge loop. When erasing one of the edges of the rectangle that was added, both faces disappear.

What you can try to possibly avoid this problem is to calculate all coplanar segments, not delete them, but instead put them in a list (or in the selection). Then, just delete the entities in the list (or in the selection):


model.entities.erase_entities list_edges
#or
model.entities.erase_entities model.selection

It seems to work fine on your example, and on some more complex configurations, but I did not try in the general case.

Note: manually in Sketchup, what I would use is to select all coplanar segments, put them in a group and then just delete the group. It leaves all faces intact. Unfortunately, there is no method in Ruby to make a group or a component out of existing elements!

zhuangsuph

marne

@unknownuser said:

Thanks Zack.
This could prove really useful for the bad AutoCad imports I sometimes get.

Yip, so true for me too . Very useful. Thanks for this script!

Fletch

@cerevellum said:

The order of operations:

Select some geometry

Right click, select Flattening Script

Left click on a face (this decides the plane the geometry will project to)

This doesn't work for me at all. please test on attached scene.

select all the geometry on the lower plane
Right click, select Flattening Script
Left click on a face above

FlatteningTest.zip

chango70

This seem like a useful script, shame it is still on 0.19.

cerevellum

@Fletch
Hey, I took a look at the test model. The script doesn't work on curves yet. Basically, if you were to explode any curves it should work fine!

@chango70
Yeah, I stopped working on this script a while back (1 year?). Hopefully, I will be able to finish it up soon enough. Probably will ensure this script works inside Groups and works with curves as well.

Thanks! BTW, the original version of this had an arbitrary axis, something that could be useful as well. Perhaps the next steps are to rework the code to include this feature, or maybe to include a dialog box with several options to choose from?

pilou

@Gaieus
about the "Remove unused edges"
It works fine only if you have first used "Remove inner faces"

Gaieus

IF you have inner faces. If edges on an outer face are there because they define inner faces, they certainly aren't "unused". In any case, you should (almost) never model with inner faces.

pilou

@unknownuser said:

In any case, you should (almost) never model with inner faces.

Imagine that you build a "cuboïd snake" or any similar concepts with the Push Pull Tool + CTRL
(that is very speedy practical building and other method don't really yet exist for that)
My "remove inner faces" will be very useful at the end for after remove coplanar edges not wanted!
(here 5 visible (except "eyes & noze") before killing

thomthom

@cerevellum said:

Hi Ray and Bob,

This is something I've noticed while working on my flattening script, and I still haven't figured out why it happens. The simplest way of reproducing this is to draw a box, add a rectangle to the top surface and connect it with a line to the outer edge loop. When erasing one of the edges of the rectangle that was added, both faces disappear.

[attachment=1:2xv3js9g]edgeFaceEraseExFinalA.jpg[/attachment:2xv3js9g]

However, if you were to erase the edge that connects both edge loops first, then you can erase the edges of the inside rectangle just fine. It apparently has to do with the order in which you erase coplanar edges. Delete edges in the following order: edges connected to 0 faces go first, then edges connected to 1 face, and finally edges connected to 2 faces.

[attachment=0:2xv3js9g]edgeFaceEraseExFinalB.jpg[/attachment:2xv3js9g]

See ya,
Zach

This explains some of the oddities when I tried to write a script to remove co-planar lines. I found that existing some times didn't work - especially on messy triangulated stepped terrain imported from Max. I tried to write my own version - got pretty close, but all versions had some issues. But from this post - I got some new ideas I'd like to try.

thomthom

@cerevellum said:

However, if you were to erase the edge that connects both edge loops first, then you can erase the edges of the inside rectangle just fine. It apparently has to do with the order in which you erase coplanar edges. Delete edges in the following order: edges connected to 0 faces go first, then edges connected to 1 face, and finally edges connected to 2 faces.

[attachment=0:p7r2k6cj]edgeFaceEraseExFinalB.jpg[/attachment:p7r2k6cj]

That line that connects the two squares has two items in it .faces array - both referring to the same face.

I've also come across times when you have a face inside another face. They have one vertex that they share. All the edges in the inner face is also part of the outer face. Some weird cross loop. If you delete one of the edges of the inner face, you'll affect the outerface and it's disappear. It's one of them things that makes removing co-planar edges really hard.

One of my versions has been to recreate the geometry - but even that didn't work perfectly.

thomthom

Here's a sample of such a loop. I just moved the vertex of the connecting line onto the outer edge. There are other cases when this happen as well.
If you try to delete any of the edges of the internal face you'll also delete the outer face.

Crossloop.skp