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From: PaQ
I couldn't resist, but Plasticity mesher is really far behind MoI. (Plasti Left, MoI right, around 5500 pts budget, default settings)
I only care about Ngones output because I don't want to deal with micro triangles later on.
Plasti does create many weird stuffs, like those doubles edges, strange edges alignment ... I have the feeling ngones output 'just' try to post merge coplanar triangles or something.
Of course as Michael explains, the topo is not that important as both geo here render the same.
However when it comes to geometry manipulation (uv unwarping, sub-material assignement), MoI ngones are freaking crisp.
(There is still a lot of misunderstanding about what constitutes 'good' topology for users coming from purely polygonal modeling, as they are accustomed to creating evenly quad-dominant meshes to combat issues with average normal computation)
Image Attachments:
PlastyVsMoI.JPG
From: Michael Gibson
Hi PaQ,
re:
> I have the feeling ngones output 'just' try to post merge coplanar triangles or something.
It certainly looks like it's doing something like that. It seems like it has a tendency to get a kind of diagonal skew effect in the last connections approaching a trim edge. It kind of feels like hair that won't comb out straight. Like it's got split ends.
MoI's mesher generates N-gons natively as part of the meshing process. If you want triangles it still generates n-gons initially internally and then the n-gons are triangulated.
re:
> as they are accustomed to creating evenly quad-dominant meshes to combat issues
> with average normal computation
The other thing that drives this is using all quads with edge flow structure for sub-d modeling.
They get used to hearing over and over that they need to use all quads for their sub-d models and then that gets extended to everything needs to be all quads no matter what is being done.
- Michael
From: rom
Usually those settings (on the left)
avoid smaller than=3 and aspect ratio limit=2
allow me to get kinda tolerable topology but create excessive polygons (light blue) and long triangles marked in green which I can suppress with Max's Welder modifier.
BTW is it possible to add weld radius value next to "weld vertices along edges"?
I dream one day the FBX Exporter would generate a cleaner output similar to Smooth Bridge (the example on the right)
https://www.youtube.com/watch?v=DzBid27gDRMImage Attachments:
moi-ok4.png
From: Michael Gibson
Hi rom,
> allow me to get kinda tolerable topology but create excessive polygons (light blue) and
> long triangles marked in green which I can suppress with Max's Welder modifier.
Ok, but I hope you understand now that there is no difference in render quality from doing this.
re:
> BTW is it possible to add weld radius value next to "weld vertices along edges"?
The welding option is for whether to make single shared vertex on edges between 2 surfaces, or whether each surface should have separate vertices stacked on top of each other along their joined edges.
A radius value would be a pretty different thing, more like a polygon post processing operation.
- Michael
From: Michael Gibson
There's also an option you can set in moi.ini CentroidTriangulation=y which will triangulate n-gons with an alternate method by adding in a centroid point.
It could give you less skinny triangles.
Some more description in this thread:
https://moi3d.com/forum/index.php?webtag=MOI&msg=8109.1
- Michael
From: rom
>>>Ok, but I hope you understand now that there is no difference in render quality from doing this.
You hope in vain :)
This is DEFAULT obj from MOI with some carpaint and hdri. I'm afraid I DO see problems in renders, not matte viewport screenshots.
Can't you see how bad those perpendicular triangles are?
Image Attachments:
default-obj.png
From: rom
and this is DEFAULT obj from plasticity without perpendicular triangles.
I don't know how else to demonstrate they are bad and this issue need to be addressed
Image Attachments:
defaul_plasticity.png
From: rom
Ngoned default obj from MOI. 1000 tris for one fillet
Image Attachments:
moi-ngon-default.jpg
ngon2.png
From: val2
I use blender/cycles regularly. I build in moi and send the files over to blender. I'm attaching your test model. I gave it a metal material and lit it with a hdri. the export as a mesh is default.
Image Attachments:
test.jpg
From: Michael Gibson
Hi rom, what happens if you edit moi.ini (Options > General > "Edit .ini file" button) and set CentroidTriangulation=y then export with Output: Quads & Triangles, does that get rid of the offending triangles?
Can you describe a bit more about how you are doing the import, like which file format you are using and are you doing any editing of the model after the import?
- Michael
From: PaQ
Actually rom was right about those micro triangles render problem, I never notice it because those "glitches" are really limited when using Ngones export tho. (It might depend of the render engine or the way internal triangulation is respected ?).
Using CentroidTriangulation=y completely fix the problem here, less pleasant topo (visually) but perfect triangulated render mesh.
centroid off vs centroid on.
Image Attachments:
Centroid.JPG
From: PaQ
However the centroid triangulation option doesn't seems to help when using ngones export (.FBX). It looks like the internal triangulation (middle picture) can still produce this little nasty triangles.
Here's a first fix (Houdini) to 'correctly' triangulate those ngones. However I have to admit I have no clue what a 'centroid triangulation' is ... So I used the uv's as geometry position, triangulate it using a special "avoid small angle" in Houdini, and I restore the geometry position (while keeping vertex normals safe).
Attachments:
CadTriFix.hiplc
Image Attachments:
CadTriFix.JPG
From: rom
@Michael everything is default really (both export and import) - you could post your default obj mesh and I will show you. Or, even better: in C4D assign metallic material, get closer and to the fillet and play with light direction. IDK how one could expect good results with such a problematic topology.
I'll try the the .ini trick tomorrow..
@PaQ at last Haleluya, thank you for confirming!
With Ngons situation is really bad (post 18), with triangulation - better (p#15)
@val2 you are fine because of the distance and maybe higher poly count, get closer to the fillet area, rotate the light and see what those triangles do.
From: PaQ
Hey Rom, well I never notice that problem (in such extreme way) using Ngones with Houdini + Karma/3Delgiht/Mantra. So chances are it's also a matter of file format + DCC/Render Engine.
(.FBX is probably better to use to deal with Ngones ?). But you are right that using MoI tris export without that centroid (.ini) option "on" produce very nasty connections that result into odd reflection.
From: rom
>>>So chances are it's also a matter of file format + DCC/Render Engine.
(.FBX is probably better to use to deal with Ngones ?)
Bad mesh is bad in any DCC. MOI's export preview is rather schematic and hides the bare truth :)
On attached pic: The default triangulated fbx inside Sketchup without any fancy metallic shader.
You know where I see TONS of those ugly fillets? On furniture manufacturers sites like Vondom, Kettal, B&B etc.. They design their master pieces in NURBS programs like Rhino and then translate models with defaults settings to FBX\OBJ\3DS - the results are awful almost on any fillet.
I really hope Michael could find some elegant solution..
Image Attachments:
su.png
From: Michael Gibson
Hi rom, when you export with n-gons, there aren't any triangles stored in the file. The receiving application will generate its own triangulation of the n-gon, or with FBX it's possible to use triangulation from the FBX library code which is what tends to make FBX have more uniform behavior.
I wonder if your render engine and current settings are particularly sensitive to skinny triangles.
Does your renderer use raytraced shadows? What happens if you turn that off, do the darkest spots go away?
- Michael
From: PaQ
I know nothing about Sketchup, but this example here looks like "you" simply f**** up the baked vertex normal.
While I do agree about the issue pointed previously (that again can be fixed using the centroid .ini option), what you call 'bad topology' is irrelevant if you handle the baked vertex normals correctly, meaning, don't touch it, don't discard it, don't post modify the topology unless you know what you are doing.
Also it would be more productive if you give a little more info about the DCC/Render engine you are targeting. I did created tons of large rendering (8-20k) using mesh coming from MoI without much issues, at least no more that all the crap you can get with 'traditional' modelling. (usually coming from mistakes not really visible when working in the viewport, but get revealed at rendertime).
From: PaQ
Hi Michael, I guess the "non centroid triangulation" tri-export will showcase those tiny triangle connection problem in any render engine really, especially on reflective surface, but also on self ray-trace shadow (along with the usual shadow terminator problems).
... once centroid option is activated everything is fixed.
Do you think the Ngones .FBX internal triangulation could benefit from this centroid triangulation too ? I don't trust my Hou setup that much :P
Image Attachments:
CentoidTriangluationRender.JPG
NonCentoidTriangluation.JPG
NonCentoidTriangluationRender.JPG
From: Michael Gibson
SketchUp was never really designed to have curved objects in it at all. There isn't any way (at least last I checked in the SDK) for it to contain vertex normals so it's inevitably going to have shading problems.
However, with this particular case it looks like maybe the skinny triangles might be reversed as well. That may be the larger problem.
re:
> Do you think the Ngones .FBX internal triangulation could benefit from this centroid triangulation too ? I don't trust my Hou setup that much :P
I guess so but that would be a long process to try and get Autodesk to change that.
I kind of remember there may be an option to supply a triangulation, maybe I should do that.
- Michael
From: PaQ
I see, I didn't know that would involved Autodesk :S
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