Triangulize with X method

Forums Houdini Lounge Triangulize with X method

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Unaided: Member; 49 posts; Joined: Feb. 2007; Offline

March 10, 2014 11:33 a.m.

How I can triangulize primitve of n-gons with X method?

Thanks

Attachments:
si_triangulate.jpg (44.6 KB)
houdini_triangulate.jpg (35.6 KB)


tamte: Member; 8583 posts; Joined: July 2007; Online

March 10, 2014 12:08 p.m.

PolyExtrude SOP
set Local/Scale to 0, 0

Tomas Slancik
FX Supervisor
Method Studios, NY


Unaided: Member; 49 posts; Joined: Feb. 2007; Offline

March 10, 2014 5:05 p.m.

Thanks tamte, I try it!

However, thus duplicate polys, yes? If true, then I have must to do welding points to merge polys overlapping.


anon_user_37409885: Member; 4189 posts; Joined: June 2012; Offline

March 10, 2014 5:13 p.m.

Remesh also works

Attachments:
Screen Shot 2014-03-11 at 10.12.36 am.png (125.9 KB)
Remesh.hip (55.4 KB)


tamte: Member; 8583 posts; Joined: July 2007; Online

March 10, 2014 5:19 p.m.

Unaided
Thanks tamte, I try it!

However, thus duplicate polys, yes? If true, then I have must to do welding points to merge polys overlapping.

correct, so to avoid having duplicated polygon:
on the same Polyextrude SOP go to Options tab and uncheck Output Front

Tomas Slancik
FX Supervisor
Method Studios, NY


Unaided: Member; 49 posts; Joined: Feb. 2007; Offline

March 11, 2014 4:16 a.m.

Thanks to both!

I try to duplicate polys method from tamte, and I see instead of double points how I hoped, the local scale is not center of ngon. See screenshots.

The remesh operator works fine!

Attachments:
houdini_divide1.jpg (117.1 KB)
houdini_divide0.jpg (104.2 KB)


tjeeds: Member; 339 posts; Joined: Aug. 2007; Offline

March 11, 2014 7:41 p.m.

You'd also need to append a Fuse SOP to consolidate the points, if you wanted to go the extrusion route.

Jesse Erickson
Fx Animator
WDAS


tamte: Member; 8583 posts; Joined: July 2007; Online

March 11, 2014 8:28 p.m.

tjeeds
You'd also need to append a Fuse SOP to consolidate the points, if you wanted to go the extrusion route.

this is not necessary as PolyExtrude SOP is handling that for you by default (Options/Consolidate Points Parm)

Tomas Slancik
FX Supervisor
Method Studios, NY


tjeeds: Member; 339 posts; Joined: Aug. 2007; Offline

March 11, 2014 8:41 p.m.

Also correct, but you do have to raise the tolerance as 1e-05 is too small to do the consolidation.

Jesse Erickson
Fx Animator
WDAS


tamte: Member; 8583 posts; Joined: July 2007; Online

March 11, 2014 8:56 p.m.

well, for this case it works (at least for me) as you are scaling each polygon to 0
and the only thing is that even after consolidating points to single one it is not removing 0 area polygon so that why is necessary to uncheck Output Front

but you are right, it never hurts to increase the tolerance to be sure
it's all about the scene scale afterall

Tomas Slancik
FX Supervisor
Method Studios, NY


tjeeds: Member; 339 posts; Joined: Aug. 2007; Offline

March 11, 2014 9:08 p.m.

Yeah, I would have thought that would do the trick too, it's supposed to anyway! I get 7 points out of the polyextrude, so the default consolidation gets all but one of the points. Looks like performance varies with orientation though, rotating it causes the point count to fluctuate between 6 and 8 points

Not a big deal I guess but kinda weird

Jesse Erickson
Fx Animator
WDAS


Unaided: Member; 49 posts; Joined: Feb. 2007; Offline

March 12, 2014 4:20 p.m.

Using Remesh op applied to a primitive not run how I was hope.

The PolyExtrude method don't find correctly the center of each n-gon. For instance over dodecahedron.

I looking something like X method of triangulate in Softimage, or Poke Faces in Blender.


anon_user_37409885: Member; 4189 posts; Joined: June 2012; Offline

March 12, 2014 4:24 p.m.

So what does this procedure actually do and how does it do it?

Reading an old post looks like we are jsust rehashing this in Houdini

http://blenderartists.org/forum/archive/index.php/t-58889.html [blenderartists.org]


pezetko: Member; 387 posts; Joined: Nov. 2008; Offline

March 12, 2014 5:49 p.m.

Beauty of Houdini is that you can make your own tools easily and fast.

In attachment is example how to solve subdivide X method (with correct center for new points). (It could be probably optimized without using forEach sop).

You can make HDA from subnet and reuse it whenever you need it.

Attachments:
subdivide_x_pz_v01.hipnc (106.8 KB)


tomsvfx: Member; 54 posts; Joined: Aug. 2011; Offline

March 12, 2014 5:52 p.m.

check my file in attachement.
I made few variations on how to do this thing, but using OpenSubdivision Bilinear type, seems like will do what you need.

Its not specificly in X axis, but i dont see much of a difference, result is the same. Or i just dont understand what youre trying to achieve with this

Cheers,
Tom

Edit: checked pezetko post, now i understand what u need, well, atleast i tried

EDIT2:
I added another file, with new example, wich is closer to what you need. Added also some notes, if need to explain something just ask it.
Its not perfect, but it does something, and it can be used as a starting idea.

Attachments:
sops_17_triangles.hip (103.9 KB)
sops_17_triangles_added_one more_example.hip (133.3 KB)


tjeeds: Member; 339 posts; Joined: Aug. 2007; Offline

March 12, 2014 7:12 p.m.

Aaaaand here's how to do it in VEX

Does not interpolate attributes though

Attachments:
pokeface.hip (70.3 KB)

Jesse Erickson
Fx Animator
WDAS


Unaided: Member; 49 posts; Joined: Feb. 2007; Offline

March 13, 2014 3:35 a.m.

pezetko, your file show me warnings pop-up and nothing is loaded in scene.

tjeeds, same, warning pop-up appears to me, and not applied your tool over socceball.

Maybe version issues? I have use Houdini 12.5.

toms993, I looking for pokefaces (Blender) or triangulate X method (XSI). This is not subdivision or local-subDv. The first methods find the geometric center of a any shape geometry, and add edges from this center to each vertices of the boundary shape.

I don't thought make this would be so complex!

Attachments:
pokefaces_tjeeds.jpg (56.6 KB)
subdivide_x_pz_v01_pezetko.jpg (68.4 KB)


pezetko: Member; 387 posts; Joined: Nov. 2008; Offline

March 13, 2014 6:35 a.m.

tjeeds: Thank you for the pure VEX example, that speed gain is incredible.

naided: Try to open it in 13.0.314


tjeeds: Member; 339 posts; Joined: Aug. 2007; Offline

March 13, 2014 1:45 p.m.

H13 added the ability to create and destroy geometry in vex, which is totally badass.

Jesse Erickson
Fx Animator
WDAS


Unaided: Member; 49 posts; Joined: Feb. 2007; Offline

March 13, 2014 3:14 p.m.

Thanks pezetko, your tool works fine in 13.0.314. Is a complex tool for me, but runs perfectly with regular-shape primitives

Also works fine in H13 your tool, tjeeds.

Thanks a lot!

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