Morphography tutorials
Scale of Models in Poser
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Introduction

So, what is all this scale stuff, anyway?

Unlike physical objects, computer models have no intrinsic size. The files which define their X, Y and Z coordinates contain only numbers. It's up to the program that handles them to impose a correspondence between these numbers and real-world units of measurement.

Poser uses the Wavefront OBJ format to define geometry. That's what you'll find in all those files in the Geometries folder. Open one up in a text editor, and you'll find long lists of numbers, like this:

v -0.009852 0.010000 -0.049530
v -0.009852 0.000000 -0.049530
v -0.009657 0.000000 -0.048549

Apart from the letter v, which simply says that these are vertex coordinates, the three numbers in each row are respectively the X, Y and Z coordinates for a single vertex, defining a position in 3D space. Later on in the file, these vertices are used to define a surface and hence the model - but the concept of scale starts right here. When we see an X coordinate of -0.009852, as we do on the first two lines here, what distance actually is that? We can say that it's to the left of the origin, because of the minus sign, but how far left? The diameter of a hydrogen nucleus? Three and a half cubits? The best part of a lightyear? It could be literally anything. We need a scale factor to relate these numbers to feet and inches, metres, or whatever.

Poser actually has at least three scale factors vying for supremacy. Fights occasionally break out on the forums as their proponents argue for their chosen scale. The numbers in the OBJ geometry files (and also to be found in embedded geometry inside prop files and the like) are referred to as Poser Native Units, or PNU for short. And the nominees for the scale factor are:

The reason for all this is that originally, Poser had no scale stated. The dial settings were just arbitrary numbers, and until Poser 5 was released there was no option to set them to real-world units. Of course, people still wanted to build props, and of course they wanted them to look "right" when seen next to the human figures that were included with the program. So the Poser community invented their own scale factors.

The 1 PNU = 96 inches scale makes the Poser 4 man just over six feet tall, and this was adopted by many modellers. An alternative scale of 1 PNU = 100 inches was popularised by Renderosity member Dr. Geep, because it makes mental arithmetic easier when modelling in native units - I used it in my early props. The P4 man is six feet three-and-a-quarter inches tall by that scale, which is not unreasonable.

You can see already that the concept of scale is a fluid one - everything is relative to everything else. You can't say how tall the P4 man is until you see him standing next to something familiar - and it can be hard to judge the size of an unfamiliar object until you see someone standing next to it.

Poser's scale settings

As I said, versions of Poser from 5 onwards have preference settings for scale. You can choose between Poser native units, inches, feet, millimetres, centimetres or metres. All well and good, but not as useful as it may seem. For a start, the scale used in Poser 5 (and also, I believe, in DAZ|Studio) is the 1 PNU = 96 inches one - but from Poser 6 onwards, that changed to 1 PNU = 8.6 feet. We ordinary mortals don't stand a chance when building on shifting sands such as those.

To make matters worse, the makers of Poser content have not been consistent either. Victoria 4 is nearly as tall as the Poser 4 man, for example, and whereas 6 foot 4 is quite tall for a man, it's quite exceptional for a woman. Yet that's how tall Vicki is if you measure her height in Poser 6 or later. In Poser 5, Victoria 4 measures a more reasonable 5 feet 10 and a half, which although tall for a woman, isn't all that unlikely. Gisele Bundchen, Rachel Hunter, Nicole Kidman and Carly Simon are reckoned to be that tall, for example. (See http://www.tallwomen.org/famous/.) You won't find many women in the 6 feet 4 and over section, though.

Other modellers' scale settings

When we get onto the subject of other 3D modelling programs, an already knotty question just becomes totally confusing. This table summarises the DAZ|Studio OBJ import presets for a variety of applications. It doesn't mean that they can't operate at other scales, but these figures are regarded as being reasonable defaults. Thanks to Richard Haseltine for this information.

The figures are presented in ascending order of the size of a native unit - which I've called PNU elsewhere in this article.

1 unit = 1 cm DAZ|Studio, Hexagon, Maya
1 unit = 2.5cm XSI
1 unit = 1 inch Carrara
1 unit = 10 cm Silo
1 unit = 50 cm Blender
1 unit = 1 metre Cinema 4D, Lightwave, 3DStudio Max, Mirai, Modo
1 unit = 8 ft Bryce, Poser

You can see that the rest of the 3D world is also in a state of disarray. The effect of all this is that a model made in an application high in the list will appear progressively larger when imported into one below it. For example, a Hexagon model would appear to be about 244 times larger when imported into Poser. Conversely, a model from an application low on the list will appear smaller in a higher app. Poser has a reputation for using "tiny" models, and you can see how that came about - but it's all relative really, like everything in this universe.

Measurements

Here's a table which summarises the effects of these scale conventions, by showing what the height of various figures effectively become when using them, ordered by ascending height.

  Poser 5 or DAZ|Studio scale DGS (Doc Geep's Scale) Poser 6 onwards scale
  1 PNU = 96 inches 1 PNU = 100 inches 1 PNU = 103.2 inches[2]
  1 PNU = 8 feet 1 PNU = 8ft 4in 1 PNU = 8ft 7.2in
  1 PNU = 2.4384m 1 PNU = 2.54m 1 PNU = 2.62128m
Figure PNU Feet Inches Metres Feet Inches Metres Feet Inches Metres
Steph 4 0.65306 5 2.7 1.59 5 5.3 1.66 5 7.4 1.71
Miki 4 0.65845 5 3.06 1.60 5 5.69 1.67 5 7.79 1.72
Miki 2 0.65845 5 3.2 1.61 5 5.9 1.67 5 8.0 1.73
Alyson P8 0.66034 5 3.39 1.61 5 6.03 1.68 5 8.15 1.73
Alyson 2 P9 0.6612 5 3.48 1.61 5 6.12 1.68 5 8.24 1.73
Roxie P10 0.6672 5 4.05 1.63 5 6.72 1.69 5 9.95 1.78
Poser 1 Man 0.67781 5 5.1 1.65 5 7.8 1.72 5 10.0 1.78
David 3 0.68252 5 5.5 1.66 5 8.3 1.73 5 10.4 1.79
Steph 3 0.6828 5 5.6 1.66 5 8.3 1.73 5 10.5 1.79
Aiko 3 0.68341 5 5.6 1.67 5 8.3 1.74 5 10.5 1.79
Poser 2 Man 0.68969 5 6.2 1.68 5 9.0 1.75 5 11.2 1.81
Jessi G2 0.69613 5 6.8 1.70 5 9.6 1.77 5 11.8 1.82
Olivia G2 0.69728 5 6.9 1.70 5 9.7 1.77 6 0.0 1.83
Sydney G2 0.6975 5 7.0 1.70 5 9.8 1.77 6 0.0 1.83
100% figure[1] 0.6975 5 7.0 1.70 5 9.8 1.77 6 0.0 1.83
Antonia 0.69922 5 7.1 1.70 5 9.9 1.78 6 0.2 1.83
Dina 0.69988 5 7.2 1.71 5 10.0 1.78 6 0.2 1.83
Posette P4 0.707264 5 7.9 1.72 5 10.7 1.80 6 1.0 1.85
Jessi P6 0.70805 5 8.0 1.73 5 10.8 1.80 6 1.1 1.86
Kiss 0.71523 5 8.7 1.74 5 11.5 1.82 6 1.8 1.87
Angela 0.71868 5 9.0 1.75 5 11.9 1.83 6 2.2 1.88
Ryan P8 & P9 0.72027 5 9.15 1.76 6 0.03 1.83 6 2.33 1.89
Victoria 3 0.72077298 5 9.2 1.76 6 0.1 1.83 6 2.4 1.89
Judy P5 0.7218 5 9.3 1.76 6 0.2 1.83 6 2.5 1.89
Rex P10 0.7281 5 9.9 1.78 6 0.81 1.85 6 3.14 1.91
Eroko 0.72811 5 9.9 1.78 6 0.8 1.85 6 3.1 1.91
Victoria 4 0.73372 5 10.4 1.79 6 1.4 1.86 6 3.7 1.92
Loretta LoRez 0.73415 5 10.5 1.79 6 1.4 1.86 6 3.8 1.92
Pauline P11 0.73564 5 10.62 1.79 6 1.56 1.87 6 3.92 1.93
Dawn 0.73607 5 10.7 1.79 6 1.6 1.87 6 4.0 1.93
Victoria 2 0.73725 5 10.8 1.80 6 1.7 1.87 6 4.1 1.93
KEZ 0.74291 5 11.3 1.81 6 2.3 1.89 6 4.7 1.95
KOZ 0.74291 5 11.3 1.81 6 2.3 1.89 6 4.7 1.95
Lorenzo LoRez 0.74626 5 11.6 1.82 6 2.6 1.90 6 5.0 1.96
Dork P4 0.752517 6 0.2 1.83 6 3.3 1.91 6 5.7 1.97
Simon G2 0.75422 6 0.4 1.84 6 3.4 1.92 6 5.8 1.98
Don P5 0.7564 6 0.6 1.84 6 3.6 1.92 6 6.1 1.98
Michael 3 0.75895 6 0.9 1.85 6 3.9 1.93 6 6.3 1.99
Michael 4 0.75905 6 0.9 1.85 6 3.9 1.93 6 6.3 1.99
Michael 2 0.75915 6 0.9 1.85 6 3.9 1.93 6 6.3 1.99
James P6 0.76005 6 1.0 1.85 6 4.0 1.93 6 6.4 1.99
Apollo Max 0.76123 6 1.1 1.86 6 4.1 1.93 6 6.6 2.00
Dusk 0.78749 6 3.6 1.92 6 6.75 2.00 6 9.27 2.06

Apart from the DAZ generation 4 figures, all the figures' heights were measured by examining their un-posed meshes (imported from the Geometries folder) in STOMP. This gives minimum and maximum values for Y, and the difference between them is the effective height in PNU. Michael, Victoria and Stephanie 4 were slightly more complex, since they are modelled "on tiptoe". I zeroed everything except their feet in Poser, exported them with their feet posed flat, and measured the resulting mesh.

Practicality

Well, be that as it may, the real question should be, what should you do when setting up a scene? The answer is, rather unhelpfully, that it can depend on what the scene is.

First, imagine a typical Poser scene: a pinup consisting of a single figure, probably rendered against a plain white background. Clothed or naked, bald or with hair, with a floor or without one; it matters little. There is only the figure in view, with nothing to compare her against (or him, but we're getting into a niche market here, by comparison!) In other words, scale doesn't matter. You pin-up artists can carry on as if nothing had happened. Oh, you were doing that already...

Now let's introduce a prop; a chair, say. Immediately things have become quite complex. Everybody knows what a chair should look like in comparison to a typical human figure. We see people sitting in chairs every day, and chairs are manufactured to quite a narrow range of dimensions, apart perhaps from the ones used in junior schools.

If the chair had been modelled to the Poser 6+ scale, 1 PNU = 103.2 inches, then Victoria 4 will appear as if she is a 6' 4" woman sitting on a chair - or from another point of view, that she is a normal woman sitting on a junior chair.

As an aside, and to address a point that I've so far ignored, there's a limit to how far this relative scale can go. People's heads tend to be more similar in size than their bodies; in other words, a tall person will tend to have a smaller head in proportion to their height than a short person would. Victoria's proportions alone tend to suggest that she is quite tall, so even in a propless pin-up situation, it would be hard to believe that she is five foot nothing.

Now let's assume that the chair was modelled to the Poser 5 scale, 1 PNU = 96 inches. It will be bigger (7.5% bigger), and this is easily seen if we place the P6 chair and the P5 chair next to each other. If the same Victoria 4 sits on the P5 chair, the effect will be of a 5' 10" woman sitting on a chair.

To summarise, if you have props in your scene, first you might need to know what scale they were modelled to. For some things it doesn't matter, because they'll be far away and not really contribute to the proportions of the scene. For other familiar items, such as the chair, incorrect proportions will be apparent and can be corrected by eye, if your eye is a good one.

However other items can give you a headache. How tall should Vicki be in proportion to the undercarriage of a WWII Lancaster bomber? You might reasonably want to include that situation in a picture, yet Lancasters are not a common item in your neighbourhood superstore. Unless you're involved in restoring these machines, in which case this analogy is not for you (so just pick another one, sheesh!), you have no experience of what such a scene should look like. You need a scale reference.

Assuming you can find out the real-world dimensions of your prop, you have essentially two choices.

Choice one: Rescale your prop or props to the scale you feel best represents your chosen figure; I'd suggest the Poser 5 scale, but it's up to you.

Choice two: Re-scale your figure to match the scale of your prop; but if they're wearing conforming clothes, you will need to re-scale the clothing, re-fit their hair, and lots of other hassle.

Footnote 1

As an aside, although the 1 PNU = 96 inches scale is useful based on the figures that are currently available, I believe it is not technically correct. Quoting page 167 of the Poser 4 manual:

"When importing DXF format files, Poser considers one DXF unit equal to the male figure’s height - about six feet."

The community reasonably assumed from this that the current male figure (affectionately known as the Poser Dork) was supposed to be six feet tall.

A DXF unit is the same as an OBJ unit, which in turn is the same as a PNU for the purposes of this discussion. However none of the figures are 1 PNU tall, so maybe that quote is as inaccurate as other parts of the Poser manual. Perish the thought.

When importing a mesh of any sort, Poser offers this dialogue box, which confused newbie and experienced users alike for years. It has at last been updated in Poser 11.

You might think that the Percent of standard figure size box would set the scaling of your imported mesh, and it does; but it does so relative to its own internal idea of a standard figure, not relative to the size of your mesh - and not relative to the size of any known figure either.

Any mesh that you import with Percent of standard figure size set to 100 will be scaled - up or down, as necessary - so that its maximum dimension is 0.6975 PNU. If it's a figure, it will end up 0.6975 PNU tall. Until Sydney G2 came along with Poser 7, there hasn't been a figure in Poser who was that height.

Now if we assume that Poser's scale was originally set at 1 PNU = 103.2 inches [2] - and by "originally", I mean back when the Prop Import dialogue was written, if not before - then this mythical 100% standard figure is 5 feet 11.98 inches tall. I'm happy to call that "about" six feet.

In other words, I would suggest that Poser's scale was always intended to be 1 PNU = 103.2 inches. The Poser 1 man is 5' 10" tall by this scale, very close to the UK/US male norm quoted on Wikipedia. By the time that Poser 3 came along, the rot had already set in. The Poser Dork is 6' 5" tall by this scale, and Posette is 6' 1".



Footnote 2 (for the terminally curious)

A more precise value is 1 PNU = 103.20000458 Poser inches, but for everyday use, you'll be relieved to know that 103.2 is close enough.

Try this experiment:

You can get apparently more precise values by Y translating the box by increasing powers of ten until it reaches orbit, but you'll run into rounding errors in the interface coding which will begin to obscure your results. The rounding varies for different versions of Poser, since the user interface was re-worked for version 8. If 103.20000458 is good enough for Bagginsbill's procedural displacement calculations, it should be good enough for the rest of us. :)

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