Head and hair of object not rendering I just finished an animation of the Hulk. When I try to render the animation, the top of the head and the hair don't show up even though they do in my workspace. I asked another question regarding how the hair mesh on hulk doesn't move properly with my armature, and I have a feeling this has something to do with it. I temporarily fixed that issue by creating a skull and turning on &quot;Bone Envelopes&quot;.
Here are some pictures illustrating my issue:
Workspace:

Rendered png:

Blend File
The first issue is that you have set the hair material to be a 'Mask' material. You can disable this by going to the 'Transparency' panel in the material options for the hair material and un-ticking the box next to 'Transparency':



If you want to use transparency for the hair you can set it to 'Z Transparency' or 'Raytrace'. 

To get the hair to render as transparent you need to tell the material to use the transparency of the image you are using. On the hair material go to the texture panel and under the 'Influence' panel make sure 'Alpha' is turned on.



You can then turn the 'Alpha' value in the first screenshot to '0' as you are giving full control of the alpha over to the image.

Finally, because you are now using transparent textures, which will cast transparent shadows, you need to set both materials to 'Receive Transparent' in the 'Shadow' panel of the material options: