I want to render a page, but I need writing on both sides, and different on each side, so I need to UV map the top and bottom.

Poser can't use double sided polygons, so I have to make a cube that is very, very flat.

How flat can I make it? Can I make the height 0.0000001 Poser units? Or will that give me rendering artifacts?

Your specialist military, sci-fi, historical and real world site.

Paper thickness varies (from 'paper thin' as in a few mils all the way up to 'heavy paper').  This link has a table of weights (scroll down a little).

That said, a Poser unit (PU) is about 96-100".  So, for paper that is 0.01" thick, that is 0.01*0.01 = 0.0001 which isn't too bad.  That is, we're multiplying 1/100th of a PU by 0.01".

Polygons this close shouldn't cause render artifacts as long as the sides are facing out properly - Poser will then cull out the other side polygons as they are facing away from the camera when rendering.

Robert

C makes it easy to shoot yourself in the foot. C++ makes it harder, but when you do, you blow your whole leg off.

 -- Bjarne Stroustrup

Contact Me | Kuroyume's DevelopmentZone

Quote - I want to render a page, but I need writing on both sides, and different on each side, so I need to UV map the top and bottom.

Poser can't use double sided polygons, so I have to make a cube that is very, very flat.

How flat can I make it? Can I make the height 0.0000001 Poser units? Or will that give me rendering artifacts?

You didn't say which version of Poser you are using but if you have Poser 6 you can use
a no width double sided polygon.
Just go to the material room and put a check in the Normals_Forward box at the bottom
and that will get rid of the weird rectangles pattern.

Thanks,

I am using Poser 6, but this may be a freebie and I want it to work in other versions too.

Seems like it works fine.

Helgard

Your specialist military, sci-fi, historical and real world site.

Quote - Thanks,

I am using Poser 6, but this may be a freebie and I want it to work in other versions too.

Seems like it works fine.

Helgard

It will probably work in Poser 1 thru 4 because this is just a problem
specific to the Firefly renderer and none of them have the Firefly
renderer.  The only one it won't work with is Poser 5 because
Poser 5 doesn't have the Normals_Forward option in the
Material room like Poser 6 does.
A trick to making it work in Poser 5 is to add a small bit of
Displacement by hooking the texture map to the displacement
input and enabling Use Displacement Maps in the render settings.

Or you could mash down a cube

Quote - I want to render a page, but I need writing on both sides, and different on each side, so I need to UV map the top and bottom.

Poser can't use double sided polygons, so I have to make a cube that is very, very flat.

How flat can I make it? Can I make the height 0.0000001 Poser units? Or will that give me rendering artifacts?

I just made a paper prop that will be in the free stuff when they post it (Has holes punched in it.  Sorry).  Made it 110 units (Anim8or) by 85, with a thickness of 0.10.  Looks pretty good, I think.

John

"It will probably work in Poser 1 thru 4 because this is just a problem
specific to the Firefly renderer...."

Almost but not quite true (to be pedantic..)
In P5, using the double-sided square (or almost anything which has double-sided polys) with the P4 render can also cause artefacts. Different artefacts, and not so noticible, but there...
They show up as thin, horizontal, randomly-spaced dark lines....

Had me tearing (what remains of) my hair out for two days before I caught sight of a thread in this forum and got clued in.
Replaced all my double-sided squares (which I'd been using in my naivete 'cos I thought I was supposed to) with single-sided ones and the problem went away...

Cheers,
Diolma

Quote - "It will probably work in Poser 1 thru 4 because this is just a problem
specific to the Firefly renderer...."

Almost but not quite true (to be pedantic..)
In P5, using the double-sided square (or almost anything which has double-sided polys) with the P4 render can also cause artefacts. Different artefacts, and not so noticible, but there...
They show up as thin, horizontal, randomly-spaced dark lines....

Interesting.  Because although I almost exlusively use Poser 6 now, I still have Poser 5
loaded on my machine.  And if I use the Poser 4 renderer with Poser 5 the odd little
rectangular boxes don't show up.  They only show up when I use the Poser 5 Firefly
renderer.  But then again another reason why I almost always use Poser 6 anymore
and just don't have to worry about the Poser 5 bugs.  In fact about the only time
I fire up Poser 5 is when a Poser 5 question like this pops up.

In every case, I would avoid the use of 'double-sided' polygons.  There are just too many ways that reliance upon this will fail or turn out bad results (if not in some version of Poser, in some other application hosting the object or content).  Any way, you can't really differentially texture each side of a double-sided polygon.  You apply a texture and it 'shows through' both sides.

My solution for a cloth in one of my products, although not perfect, was to just have two very close surfaces, facing opposite directions.  In this case, there is no 'edge', but it would require extreme close-ups to see this. :)

C makes it easy to shoot yourself in the foot. C++ makes it harder, but when you do, you blow your whole leg off.

 -- Bjarne Stroustrup

Contact Me | Kuroyume's DevelopmentZone

I measured a piece of ordinary printer paper (I get it free when I turn in printer cartridges). it's 0.1 mm thick (0.004 inch).

I seem to remember dollar bills are .02" (or .002..;) thick, but that's probably easily searched (Treasury dept. web site?..;)

I wish I'd said that.. The Staircase Wit

anahl nathrak uth vas betude doth yel dyenvey..;)

"In every case, I would avoid the use of 'double-sided' polygons.  There are just too many ways that reliance upon this will fail or turn out bad results"

I totally agree. I have deleted the "2-sided" square from my props library (in both P5 & P6).
Why on earth it was originally included in Poser is beyond me. And why it continues to be included, given the number of threads here (and elsewhere) that have asked "why am I getting these strange artefacts" just shows that someone in the Poser Development team isn't taking notice...

Normals (the thing which tells the renderer "which way is outward") are, in Poser, calculated from the vertices that make up the polygons ('cos Poser ignores any "normals" info in the .obj, as do many other apps). Normals are calculated using the order in which the polygon vertices are declared (the winding order). So if it finds 2 polys with identical vertices, one or the other will take precedence. And which one takes precedence is arbitrary (it's probably the last "identical" poly that it finds, but I don't really know). The result is, that for any 2-sided surface in Poser, 1/2 the surfaces are ignored, and the resulting normals point every whichaway.
So some are rendered properly and the rest are rendered from the wrong side.

Quite why that affects the P4 renderer in P5 (giving the above-mentioned dark lines) I have no idea, but I'm not really worried, since I now recognise the symptom and know how to deal with it.

For me, the only time it becomes a major PITA is when a 3rd party prop uses them. At least, in P5 that was the case (it meant a trip to my 3D modeller to convert all 2-sided parts of the mesh into 1-sided). At least in P6 that can usually be solved..:-))

Sorry if I'm boring you..

I'll shut up now...

Cheers,
Diolma

(stopped shutting up, for something totally OT that may or not amuse you....)

The following is impossible to do, but...

Suppose you had some paper that was 1/1,000 inches thick (that's one thousandth of an inch).
The paper is enormously large in its other dimensions (width and breadth).

Now you fold that paper in half and squeeze out all the air (that's fold 1) The thckness of the paper is now 2/1,000 inches.
With your new doubled sheet, you do the same: fold it in half and squeeze out all the air (that's fold 2) The thickness (ie height) of the folded paper is now 4/1,00 inches.

Repeat the operation for a total of 32 times (including folds 1 & 2, so that you end up with "that's fold 32").

Question: How high would the resulting stack of paper be?

Just a little something for the mathematically-inclined among you to ponder...

(Shutting up re-started...)

Cheers,
Diolma

You cannot fold paper that many times in reality... :P  The going number is about 9 folds before the thickness is too great to be overcome.

But, for the mathematical puzzle, the answer is simple - you are doubling the thickness at each fold (a power of 2).  So, it would be (2^32)/1000" = 4294967.296" (or 67.79 miles).  Note that 2^0 = 1 (unfolded).

Robert

C makes it easy to shoot yourself in the foot. C++ makes it harder, but when you do, you blow your whole leg off.

 -- Bjarne Stroustrup

Contact Me | Kuroyume's DevelopmentZone

@kuroyume:

Yup. Amazing distance, isn't it, for just 32 operations? (And I did state that "The following is impossible to do, but...")
And if you double the number of folds (to 64), you rapidly pass the orbit of the moon (become extra-circum-lunar)..:-))

Cheers,
Diolma

(Who is now going to bed!"  Got to do real work tomorrow...)

Yep.  I do see that you noted the impossibility now - but it's always nice to drag out the trivia. ;)

Good night, diolma.

C makes it easy to shoot yourself in the foot. C++ makes it harder, but when you do, you blow your whole leg off.

 -- Bjarne Stroustrup

Contact Me | Kuroyume's DevelopmentZone

I dunno..but I don't know how you get past about 4 folds (Ben folds 5, but he's special..;), unless you're Ahnold..;)

I wish I'd said that.. The Staircase Wit

anahl nathrak uth vas betude doth yel dyenvey..;)

Not to get too OT here, I can fold a piece of thin notepaper (4x6) about 6 times before it's not happening anymore.  Of course, this is not the precision folding whereas the air is removed and the thickness is strictly doubled.  That's just not possible with real paper.   The thinner the paper and the bigger the sheet, the more folds are possible up to the limit - about 9 folds - before no amount of size can help overcome the physical properties involved.

Consider that to do about 24 folds would probably require the pincing of two black holes!

Link 1

Link 2

On the other hand, some human ingenuity can push the envelope (or fold it in this case):

Link 3

See links at the bottom of Link 3 for more indepth reading. :)

Maybe some even cleverer person will come along with an alternative topological solution that allows 16 or 24 folds - one never knows.

Robert

C makes it easy to shoot yourself in the foot. C++ makes it harder, but when you do, you blow your whole leg off.

 -- Bjarne Stroustrup

Contact Me | Kuroyume's DevelopmentZone