I'm trying to get my Hair Room styling skills up to more usable state but I've run into a roadblock. Although I have "Show Populated" set, I'm only getting guide hairs to render. At first I thought this was because I had forgotten to assign a material, but I did that, and the same issue.

I do notice that although I have the Hair Density set to 500.00 (started with 30), the parentheses show "0 hairs", so something is obviously wrong there. There's also something funky going on with preview, because the same amount of hair now shows whether I have Show Populated checked or not, and no matter what I adjust the Density to.

Any ideas what's going on?

Edit: I'm using PP2012 with SR2.1, the version just released a few days ago.

Hello,

my theory is, that the hair density gives the number of hair on a unit of a square of 1 Poser display unit size (so if you have set it to m, the density must be 10,000 times higher than that you would give if your units are cm). I never got a confirmation that this theory is correct.

 For my settings of 1 m, this tells me that I have to work with hair densities of a couple of million, to get realistic images. Right now, I'm working with much lower settings (around 200 k) and thicker hair for render speed reasons.

I got no issues with  dynamic hair and would love to see more on the marketplace. At RDNA, there's a lot of dynamic hair for M1-3 / V1-3 at sale price, which is easily adjustable to work with other figures as well.

Best regards,

   Michael

P.S.: This statement was for prior SRs of Poser 2012 (0...2). I will install 2.1 to see if anything changes 

If you need densities of ~couple million, then you're using different units or something. I have rendered dynamic hair hundreds of times and never had more than a stated density of maybe a couple hundred for a given group.

I suspect I made some sort of grouping error.

Unfortunately I started again and did a whole whack of work... and Poser crashed just as I was about to save. :(

Hair Density shows two numbers, one between parentheses and one next to the dial.

The number next to the dial is the amount of hairs per square User Unit. It defaults to 32,000 hairs per square PNU (1 Poser native Unit = 262 cm). When your units are set to meters or inches, this figure is adjusted accordingly (for inches, the default will show: 3 as 3 hairs per square inch is similar to 4,500 hairs per m2 = 32,000 hairs per square PNU). You can check by altering your units settings (general prefs, Interface tab), and changing rooms (Hair to Pose and back). You value will be changed.

So when you have various adjacent hair groups that should make one fur (eg 10-part animal tail), this number should be the same on all of them.

The number between brackets is the amount of hairs generated from that density onto the hair group at hand. So the default 3 hairs / inch2 onto a 2"x2" area will generate 12 hairs. You can check by editing the hair group, just add/delete a single poly.

By taking the ratio of both numbers (hairs over density, like: 12 / 3 = 4) you can determine the size of the surface itself. Can be handy for Cloth Room as well :).

Realistic human hair is 150 (red) to 300 (blonde) hairs per cm2, a skull is about 25x20=500cm2 so one needs 75,000 to 150,000 hairs. Density then is 1,000,000 hairs per m2 (my units are meters), that's 625 per inch2.

In addition (just my experience from this weekend): mind the numbers, the amount of generated hairs * the amount of verts per hair make the vertex count of the generated hair, and each vertex takes about 1kb of memory at rendering. I had the brilliant idea of furrifying Toon Puppy (for my Hair Room tutorial) at 1M hairs/m2, it generated 1,4M hairs at 16 verts per hair and Firefly went up to (1,4m x 16 x 1kb =) 20Gb RAM. Teached me a lesson :). You can do with lesser hair but thicker. The default 1.0 root thickness (I'm still not sure if that means 1mm or 1mm2, my experiments suggest the latter) is unnaturally high anyway. 0.1 is fine for human hair (blonde), 0.2 for redheads, 0.5 for animal fur.

As I indicated earlier, in my case the problem was not with my hair density. It did not matter what I put in the Density box, the number in parentheses stayed at 0, and clicking Show Populated on or off did nothing at all.

I started over and got hair to render properly. I still think it was a glitch somewhere in my grouping process, although I'm not entirely sure what I did wrong.

Thicker hair is always possible... and less realistic. For my settings, I'm going down to about .12 at the tip and .3 at the root. Looks a lot more believable.

Am going to have to start a thread about specular colour for hair at some point.