Nurbs render?

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 From:  oz (KEVINONE)
667.1 
Hello! I use Rhino and I was just wondering why in 2007 we don't have a render that can render nurbs?, wouldn't that be nice! Rhino is great when object is a nurb, but when I export out to Lightwave the tris tend to pinch the mesh. So I try to stay with polys in Lightwave and avoid nurbs. Haven't tried MOI yet; Just wondering why no native renderer can see nurbs!
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 From:  WillBellJr
667.2 In reply to 667.1 
Yes, it is frustrating to say the least - stuff looks so good in MOI & Rhino but as you've mentioned, as soon as you export, there goes the object quality...

Granted Michael has done wonders with his poly exporter compared to Rhino - I was just looking at an old email from 2001 where I was upgrading my Rhino to v2 and I asking if there was a way to get "all quad exports from Rhino..."

Of course I know better now (wishing for an all quad export) but I agree, you'd think by now NURBS support would be better.

I've had varying success getting NURBS exports form MOI into XSI - usually all the surfaces are seperated leaving a bunch of open edges etc. A good portion of the time, nothing comes in at all...

I was interested in upgrading my Rhino v2 to v4 seeing all the improvements BUT even with all of that, if I can't get my models out, why throw away my money?

When I heard about MOI, it renewed my interest again in NURBS modeling.

The quandry is, Rhino has the power but MOI has the exporter! However I can't see myself buying v4 AND MOI just to import from Rhino to export out to my Poly apps!

To me, it's almost worth it to ask Michael to package up his exporter as a product for Rhino!

Not to take away from MOI's GUI breakthroughs, but at least it would open up a product to all the Rhino users (like me) that DO want to export cleanly into their "poly apps"...

If MOI is $200 I could see giving Michael $100 - $125 for a really comprehensive polygon exporter for Rhino - then I could get my v4 upgrade and get that exporter and be good to go...

Fortunately Michael seems to be focusing MOI in the direction of poly apps and the visual arts side of 3D where as Rhino is heavy with the machining / industrial field...

Evaluating Cinema 4D, I see it has a .3DM import type listed, but attempting even simple NURBS exports from MOI yeilds no joy so I'm not sure what's up with that!

Again, XSI does get some of the iges exports in but certainly not where I can depend on it in any kind of day to day workflow...

-Will
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 From:  Michael Gibson
667.3 In reply to 667.1 
> but when I export out to Lightwave the tris tend to pinch the mesh.

Hi Kevin, generally this is caused because LightWave does not support reading in a type of smoothing information called "vertex normals" that are stored in the mesh in OBJ files. These vertex normals actually come directly from the NURBS surface.

In this example: http://moi3d.com/forum/index.php?webtag=MOI&msg=656.16 you can see the difference between doing a rendering with accurate vertex normals and one without. In LightWave you are stuck always without.

You should contact Newtek and ask them to support importing vertex normal information so their renders can get the higher quality look as well. Currently I think that Cinema4D, Maya, and XSI can import vertex normals, so rendering NURBS objects will generally look better in those apps, they won't have that kind of pinching effect.


> <...> why in 2007 we don't have a render that can render nurbs?

It's generally due to speed - rendering the NURBS surface directly requires a tremendous amount more computations than rendering a set of polygons. Even though computers keep getting faster, it is still significant if something takes 100 times as long to calculate.

There are also different problems created by trying to directly render NURBS - it is normal for a NURBS model that has had intersections calculated on it (due to booleans, fillets, etc..) to have different surface pieces that don't touch exactly, instead they touch within a tolerance of like 0.01 or 0.001 units. When creating a mesh, these little tiny gaps are eliminated by creating shared mesh vertices along the common edges. But if you try to render the NURBS surface directly those little tiny cracks can show up, especially if you zoom in a bit.

So that's another reason why meshing is generally preferred.

But the key thing that makes NURBS mesh rendering work really well is having the accurate vertex normal smoothing information. That's the piece that is missing in Lightwave that causes shading problems.

- Michael
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 From:  Frenchy Pilou (PILOU)
667.4 In reply to 667.3 
@michael : just a question
does exist in the futur a function "print" for have the exact outlines drawing of the volumes & intersections on paper?
Like a vectorial prog
---
Pilou
Is beautiful that please without concept!
My Gallery
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 From:  Michael Gibson
667.5 In reply to 667.2 
Hi Will, Well generally it seems like MoI at $200 will already be less expensive than nearly all the Rhino plug-ins that I have seen. It's just easier for me to focus on one product right now, I don't really plan on doing a Rhino plug-in anytime soon.

Cinema4D / 3dm - They might only support reading polygon mesh data out of the .3dm file. This won't work with MoI since MoI stores only NURBS data in the .3dm file.

By far the preferred method for export to Cinema4D is by OBJ, that actually works extremely well. The final renders of the OBJ imports have NURBS level quality since the vertex normals from the actual NURBS surface are used to calculate the shading.

XSI / IGES - kind of the same story, use OBJ. XSI theoretically supports NURBS directly but it just is not an area that they have focused on for a long time, it is best to avoid that and use OBJ import again with the vertex normals enabled.

- Michael
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 From:  Michael Gibson
667.6 In reply to 667.4 
Hi Pilou!

> does exist in the futur a function "print" for have the exact outlines drawing of
> the volumes & intersections on paper?
> Like a vectorial prog

Yes, definitely in the future. It will take a lot of work to make this fully functional though.

Eventually I would like to have a different "Print" viewport, as another tab next to Split / 3D / Top / Front / Right on the bottom bar, which would let you work in a printed page layout and place 3d views, etc...

That will be some more traditional "CAD" type functionality that I do want to add.


There will be one sort of first step for this with AI export which should be coming in the next beta after today (AI _import_ is ready for today though). But that will probably be pretty basic, we'll see...

- Michael
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 From:  WillBellJr
667.7 In reply to 667.6 
Thanks Michael, yes, I realize supporting Rhino isn't your goal.

My idea for your Rhino exporter would sort of be a "Polytrans" kinda thing, focused on polygons - which would be a huge undertaking in and of itself I certainly wouldn't expect that any time soon, if at all...

It was a humorous idea for me though, you plugging up their one main deficiency; polygon exports!

Looking forward to the next beta hopefully you're still on schedule for today!

-Will

PS - I saw mentioned over at Newtek where Cinema 4D's .3DM import doesn't show anything with nurbs or polys being in the 3dm file...
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 From:  Michael Gibson
667.8 In reply to 667.7 
> Thanks Michael, yes, I realize supporting Rhino isn't your goal.

I guess it kind of is a goal in a certain sense... I do want to generally support using MoI in combination with other software including Rhino. In fact I generally recommend people to use Rhino to perform various functions that MoI does not currently do.

But yeah my focus is mostly on support through data import/export, not really in writing actual plug-in code for other systems.


> Looking forward to the next beta hopefully you're still on schedule for today!

I think so, just cleaning up some loose ends...

- Michael
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 From:  EdwinKlijn (EDWINTSI)
667.9 In reply to 667.8 
LW users have asked/begged Newtek a zillion times to support vertex smoothing.
There was even a petition on the forum, which got deleted (more then 600 people signed).

Modo (which kinda replaced LW for me) is said to support it in the upcomming 301. (betatesters told me, it hasn't been confirmed yet by Luxology).
Cinema4d DOES suport vertex smoothing. Kerkythea, a free renderer does support it as well. So exported objs's look great in it as well.
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 From:  Alienamigo
667.10 
Moi is Rock ! I love Moi !

moi - rhino - xsi

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 From:  WillBellJr
667.11 In reply to 667.10 
Yes, MOI and Rhino is a great combination - makes me glad about my Rhino purchase (investment) way back in the day! (Had hellava time trying to get my Rhino v1.1 upgraded to v2 on Vista last nite :-( Still can't get the final v2 update patch to install...)

I'm sorry to hear about that petition over at Newtek considering I posted a similar request earlier this week.

As I said, I'm not getting any younger waiting for LW to catch up with all these new generation apps and I see over at sharbor.com, there a competitive purchase deal for C4D XL...

Not that I want to spend another ~$1700 on a CAD app but if so, my LW would be up for sale that's for sure... I'm not willing to deal with workarounds while others are experiencing a smooth workflow (with up to date tools)...

I can hold off for now - MOI's lwo exports help a bit and I'm still evaluating C4D anyway...

-Will
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 From:  EdwinKlijn (EDWINTSI)
667.12 In reply to 667.11 
Just got some Moi-obj-Modo 301 renderers.
Modo 301 does support vertex smoothing and it looks great.
(great tool for 'little' money)

btw. Ngon LWO to Modo works nice as well.
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 From:  Michael Gibson
667.13 In reply to 667.10 
> Moi is Rock ! I love Moi !

I'm glad you like it! That's a beautiful smooth render.

- Michael
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 From:  Michael Gibson
667.14 In reply to 667.12 
Hi Edwin,

> Modo 301 does support vertex smoothing and it looks great.

That's great! That will be a huge improvement for rendering CAD models.

The only problem is that currently there is nothing in the LWO spec for storing vertex normals inside of a LWO file, you will only currently get them in an OBJ export.

With their new version's support, they must have some kind of extension for the LWO format for storing normals in the LWO file. If I can find out the details of that format extension, then I could write the vertex normal data to LWO as well.

- Michael
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 From:  cronbg
667.15 In reply to 667.14 
Hello Michael,

this might be an interesting bit of information: The Lightwave exporter of Okino's PolyTrans offers the option to export vertex-normals in a "modo compliant way" as they call it. Here is how they describe it on the Okino website:


"Vertex Normals (Luxology MODO Compliant)

If this checkbox is enabled then vertex normals will be output to the .lwo object file. Vertex normals are needed to make an object appear smooth.

NOTE: at this time the Lightwave software does not have support for vertex normals in the .lwo file format; however, Luxology (developers of the MODO modeling program, and original developers of the Lightwave software) have implemented their own propietry "Vertex normals" chunk in the .lwo file. Okino has implemented this MODO compliant vertex normals chunk. The VMAP and VMAD type is "NORM" and the reference name is "vert_normals". Other software developers are free to add support for this added vertex normals IFF chunk in their Lightwave importers.

This option will be disabled when the Lightwave v5.6 file format version is selected."

(http://www.okino.com/conv/exp_lw.htm)
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 From:  WillBellJr
667.16 In reply to 667.15 
Cool, hopefully Michael will be able to use this info for MOI - sounds like another checkbox is gonna be needed somewhere (or perhaps just an additional "LWO2" format specifier in the dropdown list...)

-Will
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 From:  Michael Gibson
667.17 In reply to 667.15 
Hi cronbg - thanks for passing this along, this is a useful bit of information on how to get stuff into the next version of Modo better.

I've added this data to MoI's LWO export for the next beta release, which I'm hoping to put out tomorrow.

I don't really have any way to test it to make sure it works though, because only Modo version 301 is supposed to support this and I don't have that over here. But in that version, this data should make a pretty nice difference for improving the smoothness of shading.


@Will - Actually I don't think that a checkbox will be needed for this, MoI is already saving out LWO2 style files (which still end with .lwo, they are an updated version of LWO that doesn't have the 65536 points-per-object limitation that the original LWO had). One thing that is nice about LWO files is that they are structured in such a way that programs can easily skip chunks of data that they don't recognize. So other programs that don't know how to process vertex normals should just skip right over them.

- Michael
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 From:  cronbg
667.18 In reply to 667.17 
Hi Michael,

wow, thank you so much, this is really cool!
I can't wait to get my hands on modo 301 to see how it works. This will work wonders for industrial designers like me who have to deal with a lot of NURBS and parametric solids but need high quality meshes for virtual product shots.

I think with MoI's excellent NURBS to polygon conversion capabilities, you have a real gem on your hands.

EDITED: 15 Jul 2007 by CRONBG

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 From:  WillBellJr
667.19 In reply to 667.18 
Okay great Michael, not knowing details on the LWO format, I didn't realize it was based around chunks similar to tiffs...

Glad to hear it wasn't hard for you to get this into the next beta!

Even though I've sorta settled with using Cinema 4D now (thanks to all of you folks here ;-) ), I will certainly appreciate the effort when Newtek finally gets their act a bit further into this century!

-Will
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