Rendering artifacts with Zygote wavefront format objects...

Rendering artifacts with Zygote wavefront format objects...

Post by Stephen Edwar » Wed, 01 Aug 2001 13:40:06



Greetings.  I'm having a bit of a problem with some
3D models I'm trying to use with Lightwave [6] (6.5b).

The models are wavefront format objects which are
typically used in Poser 4.  When I import them
into Lightwave, the seams which separate the
various body parts are visible both in the OpenGL
display, and in the rendered content.

So, I soon discovered that the seams in the objects
were being caused by duplicate points, so I simply
merge the points.  After that, the OpenGL display
shows a perfectly smooth and seamless object.

Once the object is rendered, it displays loads of
artifacts; ie: polygons seem to be randomly
discolored.  It's even worse when shadows are
enabled.

I have tried using double-sided surfaces, tripling,
sudividing, even qemloss2, with no luck whatsoever.

Does anyone have any ideas what is going on here?
I am at my wit's end, and I have absolutely no
idea what I am doing wrong.  Any help would be
greatly appreciated.
--
 .----.

 | = :| =====================================
 |    | http://www.users.qwest.net/~rakmount/
 |_.._| [VRML address under construction...]

 
 
 

Rendering artifacts with Zygote wavefront format objects...

Post by Brizo » Wed, 01 Aug 2001 14:00:08


http://www.geocities.com/Broadway/Stage/4003/Poser2LW/frame.html

this should help you out, it goes from getting the poser objects to LW so
covers the wavefront objects in between and should help explain how to fix
the errors your getting

hope it helps

--

-------
BriZon
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> Greetings.  I'm having a bit of a problem with some
> 3D models I'm trying to use with Lightwave [6] (6.5b).

> The models are wavefront format objects which are
> typically used in Poser 4.  When I import them
> into Lightwave, the seams which separate the
> various body parts are visible both in the OpenGL
> display, and in the rendered content.

> So, I soon discovered that the seams in the objects
> were being caused by duplicate points, so I simply
> merge the points.  After that, the OpenGL display
> shows a perfectly smooth and seamless object.

> Once the object is rendered, it displays loads of
> artifacts; ie: polygons seem to be randomly
> discolored.  It's even worse when shadows are
> enabled.

> I have tried using double-sided surfaces, tripling,
> sudividing, even qemloss2, with no luck whatsoever.

> Does anyone have any ideas what is going on here?
> I am at my wit's end, and I have absolutely no
> idea what I am doing wrong.  Any help would be
> greatly appreciated.
> --
>  .----.

>  | = :| =====================================
>  |    | http://www.users.qwest.net/~rakmount/
>  |_.._| [VRML address under construction...]


 
 
 

Rendering artifacts with Zygote wavefront format objects...

Post by Andy Woo » Wed, 01 Aug 2001 16:07:30


As wonderfull as that Poser to LW site is, I don't think it covers the
outliers you get when you bend body parts anything past slight.

"You may notice some holes in the mesh or shadows that have holes in them.
This is due to the fact that I did not allow you to triple or subdivide your
object and as a result we have some non-planar polygons. Don't worry, these
rendering errors can be easily fixed later in a paint program such as Adobe
Photoshop or PaintShop Pro."

I tried exporting a woman with her arms crossed with dreadfull result
eventualy rebuilding the elbows completely by hand, but it save me an
amazing amount of time had I to build her from scratch. I presume you could
export the model in a traditional 3D pose (arms out stretched) and use LW's
bones to bend arms as an example. Sorry I can't be more usefull than that.

Peace
Andy Wood


Quote:> http://www.geocities.com/Broadway/Stage/4003/Poser2LW/frame.html

> this should help you out, it goes from getting the poser objects to LW so
> covers the wavefront objects in between and should help explain how to fix
> the errors your getting

> hope it helps

> --

> -------
> BriZon

 
 
 

Rendering artifacts with Zygote wavefront format objects...

Post by Stephen Edwar » Wed, 01 Aug 2001 16:48:42


On that fateful day on 30 Jul 2001, some rambling man wearing a "Prepare

wrote the following schizophrenic scribblings in

Quote:>http://www.geocities.com/Broadway/Stage/4003/Poser2LW/frame.html

>this should help you out, it goes from getting the poser objects to LW so
>covers the wavefront objects in between and should help explain how to fix
>the errors your getting

>hope it helps

Thank you for the tip, BriZon.  It certainly did
help me out.  I am beginning to think that there
is something wonky about the Lightwave [6] .OBJ
importer module, though.  Even after I've tripled
the polys, they still get munged by the lighting,
especially when placed under the shadows.  There
might be an issue with the surface normals, and
how they are translated from the .OBJ format to
Lightwave.

I've tried using both exported .OBJ files, and
loading Poser's raw .OBJ geometry, with the exact
same results, so the problem is likely an issue
with the surface normals... the trick is, "where
do I start poking my nose into now?"

What's killing me is that I seem to recall having
this exact same issue with Lightwave v4.0 some time
ago, but I cannot recall what I did to fix it...
AUUUUUUUUUUUUUGGHHH!  :-)
--
 .----.

 | = :| =====================================
 |    | http://www.users.qwest.net/~rakmount/
 |_.._| [VRML address under construction...]

 
 
 

Rendering artifacts with Zygote wavefront format objects...

Post by Oskar Duvebor » Wed, 01 Aug 2001 21:18:10


I suppose it's not as simple as some duplicated polys, eh? (ie use unify)

/Weyland

 
 
 

Rendering artifacts with Zygote wavefront format objects...

Post by Stephen Edwar » Thu, 02 Aug 2001 00:24:28


On that fateful day on 31 Jul 2001, some rambling man wearing a "Prepare

Duveborn), wrote the following schizophrenic scribblings in

Quote:>I suppose it's not as simple as some duplicated polys, eh? (ie use unify)

I thought of that too... but unify doesn't seem
to remove anything.  Merge points removes some
duplicate points, but other than that, the model
appears to be flawless in the OpenGL display.
It's only when it's rendered that the artifacts
are visible.

Here are some screenshots, so you can see what
I'm dealing with:

Here's the model after I've imported it and
merged the seams of the various body parts:

http://www.veryComputer.com/~rakmount/lwprob/isgoodyaya.jpg

Now here's the model after it's loaded into the
Lightwave layout:  note to dialups:  it's 1280x1024

http://www.veryComputer.com/~rakmount/lwprob/stillokay.jpg

Now here's our *e with some sort of unsightly
disease on her skin, apparently picked up at one
of the various virtual loading docks: again, it's
at 1280x1024

http://www.veryComputer.com/~rakmount/lwprob/AUGH.jpg

I think I'm going to just have to export each
individual body part, and go through it with
a fine-toothed comb, and see if I can locate
the problem.  It's got to be something to do
with the models, because the artifacting is
also present in Lightwave v4.0 as well.

BTW, thank you for the response, and the
suggestion.
--
 .----.

 | = :| =====================================
 |    | http://www.veryComputer.com/~rakmount/
 |_.._| [VRML address under construction...]

 
 
 

Rendering artifacts with Zygote wavefront format objects...

Post by Brizo » Thu, 02 Aug 2001 00:31:49


Did you try unwelding all the poly's in the figure, welding them back
together?
or
if you've a fast machine turning on subdivision, freezing it -this will slow
down just about any machine- then use decimate or polygon cruncher to bring
the poly count down, effectivly creating a completely new mesh, which should
remove the problems if the unweld weld doesn't work. I do both usually when
using poser models, and quite like the results subdivision gives to the
poser objects (course you can miss out the freezing part if just subdivision
works well, but its slow to use on something like this)

I hope you like drinking lots of coffee / tea / smoking cigs, because the
second method will give you plenty of time to do all of them a few times
over hehe

hope that helps

--

-------
BriZon
=================/\=================
   www.lexxpark.co.uk | www.darkicefx.co.uk
                     The Web is evolving
Work: +44 (0) 771 9859450 7am - 5pm GMT
Home: +44 (0) 786 6039358 5pm - 7am GMT

          ICQ: 124947563 - MSN: Lexxpark
=================\/=================


> On that fateful day on 31 Jul 2001, some rambling man wearing a "Prepare

> Duveborn), wrote the following schizophrenic scribblings in

> >I suppose it's not as simple as some duplicated polys, eh? (ie use unify)

> I thought of that too... but unify doesn't seem
> to remove anything.  Merge points removes some
> duplicate points, but other than that, the model
> appears to be flawless in the OpenGL display.
> It's only when it's rendered that the artifacts
> are visible.

> Here are some screenshots, so you can see what
> I'm dealing with:

> Here's the model after I've imported it and
> merged the seams of the various body parts:

> http://www.veryComputer.com/~rakmount/lwprob/isgoodyaya.jpg

> Now here's the model after it's loaded into the
> Lightwave layout:  note to dialups:  it's 1280x1024

> http://www.veryComputer.com/~rakmount/lwprob/stillokay.jpg

> Now here's our *e with some sort of unsightly
> disease on her skin, apparently picked up at one
> of the various virtual loading docks: again, it's
> at 1280x1024

> http://www.veryComputer.com/~rakmount/lwprob/AUGH.jpg

> I think I'm going to just have to export each
> individual body part, and go through it with
> a fine-toothed comb, and see if I can locate
> the problem.  It's got to be something to do
> with the models, because the artifacting is
> also present in Lightwave v4.0 as well.

> BTW, thank you for the response, and the
> suggestion.
> --
>  .----.

>  | = :| =====================================
>  |    | http://www.veryComputer.com/~rakmount/
>  |_.._| [VRML address under construction...]

 
 
 

Rendering artifacts with Zygote wavefront format objects...

Post by Stephen Edward » Sat, 04 Aug 2001 00:37:38



>Did you try unwelding all the poly's in the figure, welding them back
>together?
>or
>if you've a fast machine turning on subdivision, freezing it -this will
slow
>down just about any machine- then use decimate or polygon cruncher to bring
>the poly count down, effectivly creating a completely new mesh, which
should
>remove the problems if the unweld weld doesn't work. I do both usually when
>using poser models, and quite like the results subdivision gives to the
>poser objects (course you can miss out the freezing part if just
subdivision
>works well, but its slow to use on something like this)

>I hope you like drinking lots of coffee / tea / smoking cigs, because the
>second method will give you plenty of time to do all of them a few times
>over hehe

:-)

Thanks Brizon.  I'll give it a try when I get home
from work.  It it doesn't solve the problem, I think
I'm just going to s*the project, and start from
scratch.  :-P

-Stephen