Hey all,

Thanks for all your help in my previous thread.  It really helped a ton and I'm learning a lot.  I have a more specific question this time around.

I'm trying to render hair as if the face was still there (to block the back part) so that I can composite different hairs onto the same face.   I've opened up the properties window on the head and unchecked "Visible" and although it looks like how I want in the preview cam, when I render it, you can see the back of the hair.

Here's a picture to show what I mean:
http://www.grozzler.com/dump/render.png

Is it possible to do what I want to do?  If I have 10 different hair styles / colours and 10 different make-up styles, we're looking at over 100 renders versus just 20, so ideally we can get this working.  :P

Thanks guys!

If I understand your question, you would like to make the model's head and the back of the hair invisible to your main camera.  Firstly, if the model's head is going to be invisible, then there is no need to load the model at all.  You can load the hair only for the specific model it is intended.  Secondly, the way to render the hair without the back is uncheck cast shadows in the Hair Properties and in your render settings check 'remove backfacing polygons'.  That should do the trick.

That worked a charm, thanks hborre! :)

I woke up this morning and tried to do the same thing with her Eyes but the technique isn't working.  Any ideas?

Here's the image I end up with:
http://www.grozzler.com/dump/Head_NoEyes.png

Is there no way to tell FireFly to treat the object like it's there but don't actually draw it?

Nope.  Invisibility within Poser serves several purposes.  Eliminating pokethrough is one, especially when using full body clothing and to correct offending areas due to posing.  Making select areas invisible is another particularly to concentrate on other scene aspects and composing.  Invisibility is also useful in replacing body parts with props.  However, rendering eyes invisible will not create an empty background area behind it; it will only the back of the head.  Creating a transparency map and applying it in the material room is, perhaps, the only way.

You could try a chroma key, or blue/green screen technique.  Set the materials of the parts that you don’t want to see to be an ambient color that will be easy to isolate in your image editing program.  Then open the rendered picture in the image editing software select the parts you don’t want and delete.

the main reason to load figure and hair, then make figure invisible, is to assure alignment of hair render and head render.  if hair is loaded without figure, it may be in the wrong place, wrong distance from camera, et al.  unfortunately, such a composite product of two renders is gonna look fake, like one of the banners I just saw on the upper right, where a wig of various colours was pasted over a face with different lighting than the wig.

Yeah Miss Nancy, that's why I'm trying to make it just render a part invisibly but act as if its still in the scene.  So that if you took the two images and overlayed them, you'd get exactly what you'd get as if you rendered them together.

10 hair combinations  x 10 hair colours x 10 make up options = 1,000 renders versus 30 renders that I just overlay one ontop of another.

friendly bump  The eyes technique is working great at least.  The hair is a bit of a mess but I think I can get it with Paint.NET if I keep trying.

Here are a few ideas that might help with the chroma key method.

If you are getting bleeding on the fringes from the key color you can try rendering 2 versions of the picture one with the key color and one with black instead of the key color.  Use the one with the key color to make your selection and then delete the parts you don't want on the one with the black.  Black fringes aren't as noticeable as colored fringes.

Often when I make selection I do not use the magic wand but instead will duplicate one of the color channels, touch it up (make all the parts you want to mask pure black) and use it to make a selection. 

Using a chroma key color the has an R, G or B value at a maximum of 255 this works well with using one of the color channels form making the section.  For example if I'm using a key color with a blue value of 255 I would use the blue channel from making the selection.

Quote - You could try a chroma key, or blue/green screen technique.  Set the materials of the parts that you don’t want to see to be an ambient color that will be easy to isolate in your image editing program.  Then open the rendered picture in the image editing software select the parts you don’t want and delete.

Your best bet for setting up the chroma key is to set the diffuse and specular to zero, and use the alternate diffuse for the color. That way it won't be affected by lighting or shadows.

Quote - > Quote - You could try a chroma key, or blue/green screen technique.  Set the materials of the parts that you don’t want to see to be an ambient color that will be easy to isolate in your image editing program.  Then open the rendered picture in the image editing software select the parts you don’t want and delete.

Your best bet for setting up the chroma key is to set the diffuse and specular to zero, and use the alternate diffuse for the color. That way it won't be affected by lighting or shadows.

The material shown has the diffuse and specular set to zero and is not effected by lighting and shadows.