This probably sounds dumb, but is there a good reason to use one form of units in poser instead of another?  I use feet.  I think they are nice for moving things in the pose room without needing too many big numbers and they aren't that big a unit lengthwise.  Some people use inches.  Others PNUs and others something meteric.  I'm assuming it's to personal taste, but since I don't know it for 100% and it recently came up in the forum, I thought I should ask about it.

If there's no good reason over using one or the other, should we consider informally standardizing on a meteric and assume someone is using that specific length unless otherwise stated? For example, if the mat room or someone's shaders that they share only work at or under a certain size (like raybias turned out to), it might be nice to have one standard that we can all assume everyone is using.  But maybe I'm overthinking things as usual.

Quote - If there's no good reason over using one or the other...

I use PNU  (Poser Native Units). I spend a lot of time editing Poser library files (cr2, pz2, hr2, etc). As PNU is used internally in the library files, I don't need to do any conversions to get from the value expressed in the code to the value expressed on a dial, or vice versa. I would never dream of using anything other than PNU as my default measuring unit, though I might swap to some other unit if I ware following plans for the construction of some item, where the plans used a particular unit.

For people who don't often edit Poser files, then it is not very important which units are used, and comes down to a matter of personal preference.

Quote - ... should we consider informally standardizing on a metric and assume someone is using that specific length unless otherwise stated?

Yes, the application we are using is Poser, Poser uses PNU internally, all other units are approximate conversions from PNU, so we should assume PNU unless some other unit is specified.

A Lot of answers to basic poser questions here:

http://www.drgeep.com/NPU/Directories/dir04.htm

les... as a practicle example, since it prompted this in the first place, 1 PNU is 8 feet.  The problem with ray bias came in at about 3-4 inches give or take.  4/96 ~= .0417.  For me at least, that's starting to get into the kinda small range I'd never normally use unless I knew I had to for a specific reason (I guess I think in round numbers like tenths before I start thinking in 20ths or smaller).

Doing a quick search on google, it seems to be how far off from an object a ray is cast and is used to get rid of black spots.  So that's a little counterintutive considering there is another Bias in the mat room that has to do with how much of X to apply... not from where it is applied.  So considering a plasuible difference from 8mm to 64 feet depending on your setting could really do alot if there was a way to use it as a distance measuring or depth tool in a shader.

Plus a PNU is kinda big and doesn't sound nice for fine tuning and others, not knowing what it is or caring and opting for the familiar wouldn't use it for your stated reason.

If you use Bagginsbill's shaders, use inches because that's what he uses.

Poser is based upon OBJ files which have no real world coordinate measure definitions.

1 PNU is 1 OBJ nothing more, nothing less.

Once upon a time, in Poser 4 manual there was a one-liner hint that P4 male was "about 6 feet high" (high, not tall, because it is just a mesh, not a person) and the corresponding mesh had a vertical size of .751 OBJ units so the equivalence 1 PNU == 8 feet.

I personally like to think in terms of 1 OBJ unit == 1 meter (which is also the default when using Blender in metric mode) so there is are 2.44/.41 factors when scaling from Poser/into Poser.

From the Poser 7 ReadMe...

Since Poser 6, one Poser Native Unit always is the equivalent of 8.6 feet or 262.128 centimeters.

Personally, I prefer metric units... I am used to them :-)
I can enter logical values when setting displace or bump values in the material room,
can work with numbers I know when setting camera parameters, etc.

@Winterclaw,

Quote - "Plus a PNU is kinda big and doesn't sound nice for fine tuning and others, not knowing what it is or caring and opting for the familiar wouldn't use it for your stated reason."

Like I said, which units you choose to use comes down to a matter of personal preference. My preference is for PNU as I find find it easier to work with, and it saves me a lot of time by not needing to do any conversions. But that's just me, I'm not saying that you should use PNU, use what ever works best for you.

As to the standard, PNU is the standard, because it is what Poser uses. Any other units displayed in the Poser interface are arrived at by converting the internal PNU value to that other metric, but internally Poser always uses PNU, so PNU is the de facto standard.

PNU is not a standard in Poser. For exactly the reason Les gave, I make the same argument for inches. Inches are the fundamental internal unit of materials and the material system.

Go look in a mt5 file at your bump or displacement level.

Geometry is not everything. 

Part of the problem (which has been often discussed before!) is that the default Poser human figures often don't agree with the default unit conversions.  Most of them are much taller than their proportions would indicate. 

The P6 Jessi and James were especially bad; if you set the Preferences to any of the real-world units, you'll find that Jessi is tall enough to play men's basketball, and James is too tall to fit through most standard doorways. 

I pnu is 108 inches isnt it ? I seem to remember a change between poser 6 and 7 maybe ? Its a pain to have to convert for python scripts. The metric and feet/inch thing is just local units. I have to think to figure out what 22 cm is for example.

No need to throw new random numbers out there. 1 PNU has never been 108 inches.

As stated above, it was 96 inches up to Poser 5, then 103.2 inches from Poser 6.

This does not in any way mean that characters were actually built to either of these scales. It is just that if you want to produce a 1 OBJ unit movement of a prop, you will need to use 1 PNU, or you can use 103.2 inches, or you can use 8.6 feet, etc., by choosing the other units for Poser Display Unit. These are the conversion between units as established by the program. This is for Poser 6 and up. If you were going to do the same movement in Poser 5 or less, you would convert based on 96 inches = 8 feet = 1 PNU = 1 OBJ unit.

Note that many other apps establish 1 OBJ unit = 1 meter, but this is not universal and in no way defines any sort of standard. 

PS - Dr. Geep favors the DGS system (not implemented by Poser unit system) of 1 PNU = 100 inches.

Quote - Geometry is not everything.

Are you sure? I thought it was. :blink: Well there goes string theory down the drain!

Quote - As stated above, it [a PNU] was 96 inches up to Poser 5, then 103.2 inches from Poser 6.

Yes, and the important thing to note here is that the size of a PNU did not change, that would be impossible! What changed was the size of a Poser inch. It is precisely because the size of a PNU can not change, that it is the standard.

PNU most certainly is the standard. This is because it is invariant and all other unit measurements in Poser are derived from it. It's like the wavelength of sodium light in physics, if that were to change the change would not be detectable, because all other measurements of length are derived from it, so the idea of it changing it is meaningless. The same with a PNU, if the size of a PNU were to double, that change would be absolutely undetectable, which makes nonsense out of the idea that it could change. On the other hand, the size of a Poser inch can change, as it's just a convention, not an absolute, and that's why the PNU, not the Poser inch, is the de facto standard.

BB said that "Inches are the fundamental internal unit of materials and the material system.". I'm sure he knows what he is talking about when it comes to materials. However the material room was something bolted on to Poser. Materials are not everything.

it appears there are sevl. variables that are functions of the poser unit pref.  haven't got a full list of them, nor are all (or perhaps any) discussed in manual as such.  said variables are related to optical properties, e.g. ray-tracing, shadows et al.

IMHO units are quite relative. As long as you stay in the Poser environment, it does not really matter whether 1 Poser unit equils 1 inch or feet or meter. Sometimes things matter at import or export.

Things change when you want to relate the poser universe to something in the real world. This mainly happens in the Dynamics, especially the cloth parameters.
These are in semi-metrics; cm (instead of meter), grams (instead of kg) and frames (instead of sec, 1 sec = 30 frames even when you say it's 25 in your animation).
When you switch units in Poser, these parameters do not change accordingly.  Density 0.1 means 0.1 gram/cm2 even when you set inches as the internal unit.

Hence, when you do calculations on animation combined with cloth room, working in metrics might save you from unit conversion issues. 

aRtBee,

What you say is true, the best unit to use is the one that makes life easiest for you.